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Diffstat (limited to 'src/backend/access/brin/brin_minmax_multi.c')
| -rw-r--r-- | src/backend/access/brin/brin_minmax_multi.c | 3138 |
1 files changed, 3138 insertions, 0 deletions
diff --git a/src/backend/access/brin/brin_minmax_multi.c b/src/backend/access/brin/brin_minmax_multi.c new file mode 100644 index 0000000..c045691 --- /dev/null +++ b/src/backend/access/brin/brin_minmax_multi.c @@ -0,0 +1,3138 @@ +/* + * brin_minmax_multi.c + * Implementation of Multi Min/Max opclass for BRIN + * + * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * + * Implements a variant of minmax opclass, where the summary is composed of + * multiple smaller intervals. This allows us to handle outliers, which + * usually make the simple minmax opclass inefficient. + * + * Consider for example page range with simple minmax interval [1000,2000], + * and assume a new row gets inserted into the range with value 1000000. + * Due to that the interval gets [1000,1000000]. I.e. the minmax interval + * got 1000x wider and won't be useful to eliminate scan keys between 2001 + * and 1000000. + * + * With minmax-multi opclass, we may have [1000,2000] interval initially, + * but after adding the new row we start tracking it as two interval: + * + * [1000,2000] and [1000000,1000000] + * + * This allows us to still eliminate the page range when the scan keys hit + * the gap between 2000 and 1000000, making it useful in cases when the + * simple minmax opclass gets inefficient. + * + * The number of intervals tracked per page range is somewhat flexible. + * What is restricted is the number of values per page range, and the limit + * is currently 32 (see values_per_range reloption). Collapsed intervals + * (with equal minimum and maximum value) are stored as a single value, + * while regular intervals require two values. + * + * When the number of values gets too high (by adding new values to the + * summary), we merge some of the intervals to free space for more values. + * This is done in a greedy way - we simply pick the two closest intervals, + * merge them, and repeat this until the number of values to store gets + * sufficiently low (below 50% of maximum values), but that is mostly + * arbitrary threshold and may be changed easily). + * + * To pick the closest intervals we use the "distance" support procedure, + * which measures space between two ranges (i.e. the length of an interval). + * The computed value may be an approximation - in the worst case we will + * merge two ranges that are slightly less optimal at that step, but the + * index should still produce correct results. + * + * The compactions (reducing the number of values) is fairly expensive, as + * it requires calling the distance functions, sorting etc. So when building + * the summary, we use a significantly larger buffer, and only enforce the + * exact limit at the very end. This improves performance, and it also helps + * with building better ranges (due to the greedy approach). + * + * + * IDENTIFICATION + * src/backend/access/brin/brin_minmax_multi.c + */ +#include "postgres.h" + +/* needed for PGSQL_AF_INET */ +#include <sys/socket.h> + +#include "access/genam.h" +#include "access/brin.h" +#include "access/brin_internal.h" +#include "access/brin_tuple.h" +#include "access/reloptions.h" +#include "access/stratnum.h" +#include "access/htup_details.h" +#include "catalog/pg_type.h" +#include "catalog/pg_am.h" +#include "catalog/pg_amop.h" +#include "utils/array.h" +#include "utils/builtins.h" +#include "utils/date.h" +#include "utils/datum.h" +#include "utils/float.h" +#include "utils/inet.h" +#include "utils/lsyscache.h" +#include "utils/memutils.h" +#include "utils/numeric.h" +#include "utils/pg_lsn.h" +#include "utils/rel.h" +#include "utils/syscache.h" +#include "utils/timestamp.h" +#include "utils/uuid.h" + +/* + * Additional SQL level support functions + * + * Procedure numbers must not use values reserved for BRIN itself; see + * brin_internal.h. + */ +#define MINMAX_MAX_PROCNUMS 1 /* maximum support procs we need */ +#define PROCNUM_DISTANCE 11 /* required, distance between values */ + +/* + * Subtract this from procnum to obtain index in MinmaxMultiOpaque arrays + * (Must be equal to minimum of private procnums). + */ +#define PROCNUM_BASE 11 + +/* + * Sizing the insert buffer - we use 10x the number of values specified + * in the reloption, but we cap it to 8192 not to get too large. When + * the buffer gets full, we reduce the number of values by half. + */ +#define MINMAX_BUFFER_FACTOR 10 +#define MINMAX_BUFFER_MIN 256 +#define MINMAX_BUFFER_MAX 8192 +#define MINMAX_BUFFER_LOAD_FACTOR 0.5 + +typedef struct MinmaxMultiOpaque +{ + FmgrInfo extra_procinfos[MINMAX_MAX_PROCNUMS]; + bool extra_proc_missing[MINMAX_MAX_PROCNUMS]; + Oid cached_subtype; + FmgrInfo strategy_procinfos[BTMaxStrategyNumber]; +} MinmaxMultiOpaque; + +/* + * Storage type for BRIN's minmax reloptions + */ +typedef struct MinMaxMultiOptions +{ + int32 vl_len_; /* varlena header (do not touch directly!) */ + int valuesPerRange; /* number of values per range */ +} MinMaxMultiOptions; + +#define MINMAX_MULTI_DEFAULT_VALUES_PER_PAGE 32 + +#define MinMaxMultiGetValuesPerRange(opts) \ + ((opts) && (((MinMaxMultiOptions *) (opts))->valuesPerRange != 0) ? \ + ((MinMaxMultiOptions *) (opts))->valuesPerRange : \ + MINMAX_MULTI_DEFAULT_VALUES_PER_PAGE) + +#define SAMESIGN(a,b) (((a) < 0) == ((b) < 0)) + +/* + * The summary of minmax-multi indexes has two representations - Ranges for + * convenient processing, and SerializedRanges for storage in bytea value. + * + * The Ranges struct stores the boundary values in a single array, but we + * treat regular and single-point ranges differently to save space. For + * regular ranges (with different boundary values) we have to store both + * the lower and upper bound of the range, while for "single-point ranges" + * we only need to store a single value. + * + * The 'values' array stores boundary values for regular ranges first (there + * are 2*nranges values to store), and then the nvalues boundary values for + * single-point ranges. That is, we have (2*nranges + nvalues) boundary + * values in the array. + * + * +-------------------------+----------------------------------+ + * | ranges (2 * nranges of) | single point values (nvalues of) | + * +-------------------------+----------------------------------+ + * + * This allows us to quickly add new values, and store outliers without + * having to widen any of the existing range values. + * + * 'nsorted' denotes how many of 'nvalues' in the values[] array are sorted. + * When nsorted == nvalues, all single point values are sorted. + * + * We never store more than maxvalues values (as set by values_per_range + * reloption). If needed we merge some of the ranges. + * + * To minimize palloc overhead, we always allocate the full array with + * space for maxvalues elements. This should be fine as long as the + * maxvalues is reasonably small (64 seems fine), which is the case + * thanks to values_per_range reloption being limited to 256. + */ +typedef struct Ranges +{ + /* Cache information that we need quite often. */ + Oid typid; + Oid colloid; + AttrNumber attno; + FmgrInfo *cmp; + + /* (2*nranges + nvalues) <= maxvalues */ + int nranges; /* number of ranges in the values[] array */ + int nsorted; /* number of nvalues which are sorted */ + int nvalues; /* number of point values in values[] array */ + int maxvalues; /* number of elements in the values[] array */ + + /* + * We simply add the values into a large buffer, without any expensive + * steps (sorting, deduplication, ...). The buffer is a multiple of the + * target number of values, so the compaction happens less often, + * amortizing the costs. We keep the actual target and compact to the + * requested number of values at the very end, before serializing to + * on-disk representation. + */ + /* requested number of values */ + int target_maxvalues; + + /* values stored for this range - either raw values, or ranges */ + Datum values[FLEXIBLE_ARRAY_MEMBER]; +} Ranges; + +/* + * On-disk the summary is stored as a bytea value, with a simple header + * with basic metadata, followed by the boundary values. It has a varlena + * header, so can be treated as varlena directly. + * + * See brin_range_serialize/brin_range_deserialize for serialization details. + */ +typedef struct SerializedRanges +{ + /* varlena header (do not touch directly!) */ + int32 vl_len_; + + /* type of values stored in the data array */ + Oid typid; + + /* (2*nranges + nvalues) <= maxvalues */ + int nranges; /* number of ranges in the array (stored) */ + int nvalues; /* number of values in the data array (all) */ + int maxvalues; /* maximum number of values (reloption) */ + + /* contains the actual data */ + char data[FLEXIBLE_ARRAY_MEMBER]; +} SerializedRanges; + +static SerializedRanges *brin_range_serialize(Ranges *range); + +static Ranges *brin_range_deserialize(int maxvalues, + SerializedRanges *serialized); + + +/* + * Used to represent ranges expanded to make merging and combining easier. + * + * Each expanded range is essentially an interval, represented by min/max + * values, along with a flag whether it's a collapsed range (in which case + * the min and max values are equal). We have the flag to handle by-ref + * data types - we can't simply compare the datums, and this saves some + * calls to the type-specific comparator function. + */ +typedef struct ExpandedRange +{ + Datum minval; /* lower boundary */ + Datum maxval; /* upper boundary */ + bool collapsed; /* true if minval==maxval */ +} ExpandedRange; + +/* + * Represents a distance between two ranges (identified by index into + * an array of extended ranges). + */ +typedef struct DistanceValue +{ + int index; + double value; +} DistanceValue; + + +/* Cache for support and strategy procedures. */ + +static FmgrInfo *minmax_multi_get_procinfo(BrinDesc *bdesc, uint16 attno, + uint16 procnum); + +static FmgrInfo *minmax_multi_get_strategy_procinfo(BrinDesc *bdesc, + uint16 attno, Oid subtype, + uint16 strategynum); + +typedef struct compare_context +{ + FmgrInfo *cmpFn; + Oid colloid; +} compare_context; + +static int compare_values(const void *a, const void *b, void *arg); + + +#ifdef USE_ASSERT_CHECKING +/* + * Check that the order of the array values is correct, using the cmp + * function (which should be BTLessStrategyNumber). + */ +static void +AssertArrayOrder(FmgrInfo *cmp, Oid colloid, Datum *values, int nvalues) +{ + int i; + Datum lt; + + for (i = 0; i < (nvalues - 1); i++) + { + lt = FunctionCall2Coll(cmp, colloid, values[i], values[i + 1]); + Assert(DatumGetBool(lt)); + } +} +#endif + +/* + * Comprehensive check of the Ranges structure. + */ +static void +AssertCheckRanges(Ranges *ranges, FmgrInfo *cmpFn, Oid colloid) +{ +#ifdef USE_ASSERT_CHECKING + int i; + + /* some basic sanity checks */ + Assert(ranges->nranges >= 0); + Assert(ranges->nsorted >= 0); + Assert(ranges->nvalues >= ranges->nsorted); + Assert(ranges->maxvalues >= 2 * ranges->nranges + ranges->nvalues); + Assert(ranges->typid != InvalidOid); + + /* + * First the ranges - there are 2*nranges boundary values, and the values + * have to be strictly ordered (equal values would mean the range is + * collapsed, and should be stored as a point). This also guarantees that + * the ranges do not overlap. + */ + AssertArrayOrder(cmpFn, colloid, ranges->values, 2 * ranges->nranges); + + /* then the single-point ranges (with nvalues boundary values ) */ + AssertArrayOrder(cmpFn, colloid, &ranges->values[2 * ranges->nranges], + ranges->nsorted); + + /* + * Check that none of the values are not covered by ranges (both sorted + * and unsorted) + */ + if (ranges->nranges > 0) + { + for (i = 0; i < ranges->nvalues; i++) + { + Datum compar; + int start, + end; + Datum minvalue = ranges->values[0]; + Datum maxvalue = ranges->values[2 * ranges->nranges - 1]; + Datum value = ranges->values[2 * ranges->nranges + i]; + + compar = FunctionCall2Coll(cmpFn, colloid, value, minvalue); + + /* + * If the value is smaller than the lower bound in the first range + * then it cannot possibly be in any of the ranges. + */ + if (DatumGetBool(compar)) + continue; + + compar = FunctionCall2Coll(cmpFn, colloid, maxvalue, value); + + /* + * Likewise, if the value is larger than the upper bound of the + * final range, then it cannot possibly be inside any of the + * ranges. + */ + if (DatumGetBool(compar)) + continue; + + /* bsearch the ranges to see if 'value' fits within any of them */ + start = 0; /* first range */ + end = ranges->nranges - 1; /* last range */ + while (true) + { + int midpoint = (start + end) / 2; + + /* this means we ran out of ranges in the last step */ + if (start > end) + break; + + /* copy the min/max values from the ranges */ + minvalue = ranges->values[2 * midpoint]; + maxvalue = ranges->values[2 * midpoint + 1]; + + /* + * Is the value smaller than the minval? If yes, we'll recurse + * to the left side of range array. + */ + compar = FunctionCall2Coll(cmpFn, colloid, value, minvalue); + + /* smaller than the smallest value in this range */ + if (DatumGetBool(compar)) + { + end = (midpoint - 1); + continue; + } + + /* + * Is the value greater than the minval? If yes, we'll recurse + * to the right side of range array. + */ + compar = FunctionCall2Coll(cmpFn, colloid, maxvalue, value); + + /* larger than the largest value in this range */ + if (DatumGetBool(compar)) + { + start = (midpoint + 1); + continue; + } + + /* hey, we found a matching range */ + Assert(false); + } + } + } + + /* and values in the unsorted part must not be in the sorted part */ + if (ranges->nsorted > 0) + { + compare_context cxt; + + cxt.colloid = ranges->colloid; + cxt.cmpFn = ranges->cmp; + + for (i = ranges->nsorted; i < ranges->nvalues; i++) + { + Datum value = ranges->values[2 * ranges->nranges + i]; + + Assert(bsearch_arg(&value, &ranges->values[2 * ranges->nranges], + ranges->nsorted, sizeof(Datum), + compare_values, (void *) &cxt) == NULL); + } + } +#endif +} + +/* + * Check that the expanded ranges (built when reducing the number of ranges + * by combining some of them) are correctly sorted and do not overlap. + */ +static void +AssertCheckExpandedRanges(BrinDesc *bdesc, Oid colloid, AttrNumber attno, + Form_pg_attribute attr, ExpandedRange *ranges, + int nranges) +{ +#ifdef USE_ASSERT_CHECKING + int i; + FmgrInfo *eq; + FmgrInfo *lt; + + eq = minmax_multi_get_strategy_procinfo(bdesc, attno, attr->atttypid, + BTEqualStrategyNumber); + + lt = minmax_multi_get_strategy_procinfo(bdesc, attno, attr->atttypid, + BTLessStrategyNumber); + + /* + * Each range independently should be valid, i.e. that for the boundary + * values (lower <= upper). + */ + for (i = 0; i < nranges; i++) + { + Datum r; + Datum minval = ranges[i].minval; + Datum maxval = ranges[i].maxval; + + if (ranges[i].collapsed) /* collapsed: minval == maxval */ + r = FunctionCall2Coll(eq, colloid, minval, maxval); + else /* non-collapsed: minval < maxval */ + r = FunctionCall2Coll(lt, colloid, minval, maxval); + + Assert(DatumGetBool(r)); + } + + /* + * And the ranges should be ordered and must not overlap, i.e. upper < + * lower for boundaries of consecutive ranges. + */ + for (i = 0; i < nranges - 1; i++) + { + Datum r; + Datum maxval = ranges[i].maxval; + Datum minval = ranges[i + 1].minval; + + r = FunctionCall2Coll(lt, colloid, maxval, minval); + + Assert(DatumGetBool(r)); + } +#endif +} + + +/* + * minmax_multi_init + * Initialize the deserialized range list, allocate all the memory. + * + * This is only in-memory representation of the ranges, so we allocate + * enough space for the maximum number of values (so as not to have to do + * repallocs as the ranges grow). + */ +static Ranges * +minmax_multi_init(int maxvalues) +{ + Size len; + Ranges *ranges; + + Assert(maxvalues > 0); + + len = offsetof(Ranges, values); /* fixed header */ + len += maxvalues * sizeof(Datum); /* Datum values */ + + ranges = (Ranges *) palloc0(len); + + ranges->maxvalues = maxvalues; + + return ranges; +} + + +/* + * range_deduplicate_values + * Deduplicate the part with values in the simple points. + * + * This is meant to be a cheaper way of reducing the size of the ranges. It + * does not touch the ranges, and only sorts the other values - it does not + * call the distance functions, which may be quite expensive, etc. + * + * We do know the values are not duplicate with the ranges, because we check + * that before adding a new value. Same for the sorted part of values. + */ +static void +range_deduplicate_values(Ranges *range) +{ + int i, + n; + int start; + compare_context cxt; + + /* + * If there are no unsorted values, we're done (this probably can't + * happen, as we're adding values to unsorted part). + */ + if (range->nsorted == range->nvalues) + return; + + /* sort the values */ + cxt.colloid = range->colloid; + cxt.cmpFn = range->cmp; + + /* the values start right after the ranges (which are always sorted) */ + start = 2 * range->nranges; + + /* + * XXX This might do a merge sort, to leverage that the first part of the + * array is already sorted. If the sorted part is large, it might be quite + * a bit faster. + */ + qsort_arg(&range->values[start], + range->nvalues, sizeof(Datum), + compare_values, &cxt); + + n = 1; + for (i = 1; i < range->nvalues; i++) + { + /* same as preceding value, so store it */ + if (compare_values(&range->values[start + i - 1], + &range->values[start + i], + (void *) &cxt) == 0) + continue; + + range->values[start + n] = range->values[start + i]; + + n++; + } + + /* now all the values are sorted */ + range->nvalues = n; + range->nsorted = n; + + AssertCheckRanges(range, range->cmp, range->colloid); +} + + +/* + * brin_range_serialize + * Serialize the in-memory representation into a compact varlena value. + * + * Simply copy the header and then also the individual values, as stored + * in the in-memory value array. + */ +static SerializedRanges * +brin_range_serialize(Ranges *range) +{ + Size len; + int nvalues; + SerializedRanges *serialized; + Oid typid; + int typlen; + bool typbyval; + + char *ptr; + + /* simple sanity checks */ + Assert(range->nranges >= 0); + Assert(range->nsorted >= 0); + Assert(range->nvalues >= 0); + Assert(range->maxvalues > 0); + Assert(range->target_maxvalues > 0); + + /* at this point the range should be compacted to the target size */ + Assert(2 * range->nranges + range->nvalues <= range->target_maxvalues); + + Assert(range->target_maxvalues <= range->maxvalues); + + /* range boundaries are always sorted */ + Assert(range->nvalues >= range->nsorted); + + /* deduplicate values, if there's unsorted part */ + range_deduplicate_values(range); + + /* see how many Datum values we actually have */ + nvalues = 2 * range->nranges + range->nvalues; + + typid = range->typid; + typbyval = get_typbyval(typid); + typlen = get_typlen(typid); + + /* header is always needed */ + len = offsetof(SerializedRanges, data); + + /* + * The space needed depends on data type - for fixed-length data types + * (by-value and some by-reference) it's pretty simple, just multiply + * (attlen * nvalues) and we're done. For variable-length by-reference + * types we need to actually walk all the values and sum the lengths. + */ + if (typlen == -1) /* varlena */ + { + int i; + + for (i = 0; i < nvalues; i++) + { + len += VARSIZE_ANY(range->values[i]); + } + } + else if (typlen == -2) /* cstring */ + { + int i; + + for (i = 0; i < nvalues; i++) + { + /* don't forget to include the null terminator ;-) */ + len += strlen(DatumGetCString(range->values[i])) + 1; + } + } + else /* fixed-length types (even by-reference) */ + { + Assert(typlen > 0); + len += nvalues * typlen; + } + + /* + * Allocate the serialized object, copy the basic information. The + * serialized object is a varlena, so update the header. + */ + serialized = (SerializedRanges *) palloc0(len); + SET_VARSIZE(serialized, len); + + serialized->typid = typid; + serialized->nranges = range->nranges; + serialized->nvalues = range->nvalues; + serialized->maxvalues = range->target_maxvalues; + + /* + * And now copy also the boundary values (like the length calculation this + * depends on the particular data type). + */ + ptr = serialized->data; /* start of the serialized data */ + + for (int i = 0; i < nvalues; i++) + { + if (typbyval) /* simple by-value data types */ + { + Datum tmp; + + /* + * For byval types, we need to copy just the significant bytes - + * we can't use memcpy directly, as that assumes little-endian + * behavior. store_att_byval does almost what we need, but it + * requires a properly aligned buffer - the output buffer does not + * guarantee that. So we simply use a local Datum variable (which + * guarantees proper alignment), and then copy the value from it. + */ + store_att_byval(&tmp, range->values[i], typlen); + + memcpy(ptr, &tmp, typlen); + ptr += typlen; + } + else if (typlen > 0) /* fixed-length by-ref types */ + { + memcpy(ptr, DatumGetPointer(range->values[i]), typlen); + ptr += typlen; + } + else if (typlen == -1) /* varlena */ + { + int tmp = VARSIZE_ANY(DatumGetPointer(range->values[i])); + + memcpy(ptr, DatumGetPointer(range->values[i]), tmp); + ptr += tmp; + } + else if (typlen == -2) /* cstring */ + { + int tmp = strlen(DatumGetCString(range->values[i])) + 1; + + memcpy(ptr, DatumGetCString(range->values[i]), tmp); + ptr += tmp; + } + + /* make sure we haven't overflown the buffer end */ + Assert(ptr <= ((char *) serialized + len)); + } + + /* exact size */ + Assert(ptr == ((char *) serialized + len)); + + return serialized; +} + +/* + * brin_range_deserialize + * Serialize the in-memory representation into a compact varlena value. + * + * Simply copy the header and then also the individual values, as stored + * in the in-memory value array. + */ +static Ranges * +brin_range_deserialize(int maxvalues, SerializedRanges *serialized) +{ + int i, + nvalues; + char *ptr, + *dataptr; + bool typbyval; + int typlen; + Size datalen; + + Ranges *range; + + Assert(serialized->nranges >= 0); + Assert(serialized->nvalues >= 0); + Assert(serialized->maxvalues > 0); + + nvalues = 2 * serialized->nranges + serialized->nvalues; + + Assert(nvalues <= serialized->maxvalues); + Assert(serialized->maxvalues <= maxvalues); + + range = minmax_multi_init(maxvalues); + + /* copy the header info */ + range->nranges = serialized->nranges; + range->nvalues = serialized->nvalues; + range->nsorted = serialized->nvalues; + range->maxvalues = maxvalues; + range->target_maxvalues = serialized->maxvalues; + + range->typid = serialized->typid; + + typbyval = get_typbyval(serialized->typid); + typlen = get_typlen(serialized->typid); + + /* + * And now deconstruct the values into Datum array. We have to copy the + * data because the serialized representation ignores alignment, and we + * don't want to rely on it being kept around anyway. + */ + ptr = serialized->data; + + /* + * We don't want to allocate many pieces, so we just allocate everything + * in one chunk. How much space will we need? + * + * XXX We don't need to copy simple by-value data types. + */ + datalen = 0; + dataptr = NULL; + for (i = 0; (i < nvalues) && (!typbyval); i++) + { + if (typlen > 0) /* fixed-length by-ref types */ + datalen += MAXALIGN(typlen); + else if (typlen == -1) /* varlena */ + { + datalen += MAXALIGN(VARSIZE_ANY(ptr)); + ptr += VARSIZE_ANY(ptr); + } + else if (typlen == -2) /* cstring */ + { + Size slen = strlen(ptr) + 1; + + datalen += MAXALIGN(slen); + ptr += slen; + } + } + + if (datalen > 0) + dataptr = palloc(datalen); + + /* + * Restore the source pointer (might have been modified when calculating + * the space we need to allocate). + */ + ptr = serialized->data; + + for (i = 0; i < nvalues; i++) + { + if (typbyval) /* simple by-value data types */ + { + Datum v = 0; + + memcpy(&v, ptr, typlen); + + range->values[i] = fetch_att(&v, true, typlen); + ptr += typlen; + } + else if (typlen > 0) /* fixed-length by-ref types */ + { + range->values[i] = PointerGetDatum(dataptr); + + memcpy(dataptr, ptr, typlen); + dataptr += MAXALIGN(typlen); + + ptr += typlen; + } + else if (typlen == -1) /* varlena */ + { + range->values[i] = PointerGetDatum(dataptr); + + memcpy(dataptr, ptr, VARSIZE_ANY(ptr)); + dataptr += MAXALIGN(VARSIZE_ANY(ptr)); + ptr += VARSIZE_ANY(ptr); + } + else if (typlen == -2) /* cstring */ + { + Size slen = strlen(ptr) + 1; + + range->values[i] = PointerGetDatum(dataptr); + + memcpy(dataptr, ptr, slen); + dataptr += MAXALIGN(slen); + ptr += slen; + } + + /* make sure we haven't overflown the buffer end */ + Assert(ptr <= ((char *) serialized + VARSIZE_ANY(serialized))); + } + + /* should have consumed the whole input value exactly */ + Assert(ptr == ((char *) serialized + VARSIZE_ANY(serialized))); + + /* return the deserialized value */ + return range; +} + +/* + * compare_expanded_ranges + * Compare the expanded ranges - first by minimum, then by maximum. + * + * We do guarantee that ranges in a single Ranges object do not overlap, so it + * may seem strange that we don't order just by minimum. But when merging two + * Ranges (which happens in the union function), the ranges may in fact + * overlap. So we do compare both. + */ +static int +compare_expanded_ranges(const void *a, const void *b, void *arg) +{ + ExpandedRange *ra = (ExpandedRange *) a; + ExpandedRange *rb = (ExpandedRange *) b; + Datum r; + + compare_context *cxt = (compare_context *) arg; + + /* first compare minvals */ + r = FunctionCall2Coll(cxt->cmpFn, cxt->colloid, ra->minval, rb->minval); + + if (DatumGetBool(r)) + return -1; + + r = FunctionCall2Coll(cxt->cmpFn, cxt->colloid, rb->minval, ra->minval); + + if (DatumGetBool(r)) + return 1; + + /* then compare maxvals */ + r = FunctionCall2Coll(cxt->cmpFn, cxt->colloid, ra->maxval, rb->maxval); + + if (DatumGetBool(r)) + return -1; + + r = FunctionCall2Coll(cxt->cmpFn, cxt->colloid, rb->maxval, ra->maxval); + + if (DatumGetBool(r)) + return 1; + + return 0; +} + +/* + * compare_values + * Compare the values. + */ +static int +compare_values(const void *a, const void *b, void *arg) +{ + Datum *da = (Datum *) a; + Datum *db = (Datum *) b; + Datum r; + + compare_context *cxt = (compare_context *) arg; + + r = FunctionCall2Coll(cxt->cmpFn, cxt->colloid, *da, *db); + + if (DatumGetBool(r)) + return -1; + + r = FunctionCall2Coll(cxt->cmpFn, cxt->colloid, *db, *da); + + if (DatumGetBool(r)) + return 1; + + return 0; +} + +/* + * Check if the new value matches one of the existing ranges. + */ +static bool +has_matching_range(BrinDesc *bdesc, Oid colloid, Ranges *ranges, + Datum newval, AttrNumber attno, Oid typid) +{ + Datum compar; + + Datum minvalue; + Datum maxvalue; + + FmgrInfo *cmpLessFn; + FmgrInfo *cmpGreaterFn; + + /* binary search on ranges */ + int start, + end; + + if (ranges->nranges == 0) + return false; + + minvalue = ranges->values[0]; + maxvalue = ranges->values[2 * ranges->nranges - 1]; + + /* + * Otherwise, need to compare the new value with boundaries of all the + * ranges. First check if it's less than the absolute minimum, which is + * the first value in the array. + */ + cmpLessFn = minmax_multi_get_strategy_procinfo(bdesc, attno, typid, + BTLessStrategyNumber); + compar = FunctionCall2Coll(cmpLessFn, colloid, newval, minvalue); + + /* smaller than the smallest value in the range list */ + if (DatumGetBool(compar)) + return false; + + /* + * And now compare it to the existing maximum (last value in the data + * array). But only if we haven't already ruled out a possible match in + * the minvalue check. + */ + cmpGreaterFn = minmax_multi_get_strategy_procinfo(bdesc, attno, typid, + BTGreaterStrategyNumber); + compar = FunctionCall2Coll(cmpGreaterFn, colloid, newval, maxvalue); + + if (DatumGetBool(compar)) + return false; + + /* + * So we know it's in the general min/max, the question is whether it + * falls in one of the ranges or gaps. We'll do a binary search on + * individual ranges - for each range we check equality (value falls into + * the range), and then check ranges either above or below the current + * range. + */ + start = 0; /* first range */ + end = (ranges->nranges - 1); /* last range */ + while (true) + { + int midpoint = (start + end) / 2; + + /* this means we ran out of ranges in the last step */ + if (start > end) + return false; + + /* copy the min/max values from the ranges */ + minvalue = ranges->values[2 * midpoint]; + maxvalue = ranges->values[2 * midpoint + 1]; + + /* + * Is the value smaller than the minval? If yes, we'll recurse to the + * left side of range array. + */ + compar = FunctionCall2Coll(cmpLessFn, colloid, newval, minvalue); + + /* smaller than the smallest value in this range */ + if (DatumGetBool(compar)) + { + end = (midpoint - 1); + continue; + } + + /* + * Is the value greater than the minval? If yes, we'll recurse to the + * right side of range array. + */ + compar = FunctionCall2Coll(cmpGreaterFn, colloid, newval, maxvalue); + + /* larger than the largest value in this range */ + if (DatumGetBool(compar)) + { + start = (midpoint + 1); + continue; + } + + /* hey, we found a matching range */ + return true; + } + + return false; +} + + +/* + * range_contains_value + * See if the new value is already contained in the range list. + * + * We first inspect the list of intervals. We use a small trick - we check + * the value against min/max of the whole range (min of the first interval, + * max of the last one) first, and only inspect the individual intervals if + * this passes. + * + * If the value matches none of the intervals, we check the exact values. + * We simply loop through them and invoke equality operator on them. + * + * The last parameter (full) determines whether we need to search all the + * values, including the unsorted part. With full=false, the unsorted part + * is not searched, which may produce false negatives and duplicate values + * (in the unsorted part only), but when we're building the range that's + * fine - we'll deduplicate before serialization, and it can only happen + * if there already are unsorted values (so it was already modified). + * + * Serialized ranges don't have any unsorted values, so this can't cause + * false negatives during querying. + */ +static bool +range_contains_value(BrinDesc *bdesc, Oid colloid, + AttrNumber attno, Form_pg_attribute attr, + Ranges *ranges, Datum newval, bool full) +{ + int i; + FmgrInfo *cmpEqualFn; + Oid typid = attr->atttypid; + + /* + * First inspect the ranges, if there are any. We first check the whole + * range, and only when there's still a chance of getting a match we + * inspect the individual ranges. + */ + if (has_matching_range(bdesc, colloid, ranges, newval, attno, typid)) + return true; + + cmpEqualFn = minmax_multi_get_strategy_procinfo(bdesc, attno, typid, + BTEqualStrategyNumber); + + /* + * There is no matching range, so let's inspect the sorted values. + * + * We do a sequential search for small numbers of values, and binary + * search once we have more than 16 values. This threshold is somewhat + * arbitrary, as it depends on how expensive the comparison function is. + * + * XXX If we use the threshold here, maybe we should do the same thing in + * has_matching_range? Or maybe we should do the bin search all the time? + * + * XXX We could use the same optimization as for ranges, to check if the + * value is between min/max, to maybe rule out all sorted values without + * having to inspect all of them. + */ + if (ranges->nsorted >= 16) + { + compare_context cxt; + + cxt.colloid = ranges->colloid; + cxt.cmpFn = ranges->cmp; + + if (bsearch_arg(&newval, &ranges->values[2 * ranges->nranges], + ranges->nsorted, sizeof(Datum), + compare_values, (void *) &cxt) != NULL) + return true; + } + else + { + for (i = 2 * ranges->nranges; i < 2 * ranges->nranges + ranges->nsorted; i++) + { + Datum compar; + + compar = FunctionCall2Coll(cmpEqualFn, colloid, newval, ranges->values[i]); + + /* found an exact match */ + if (DatumGetBool(compar)) + return true; + } + } + + /* If not asked to inspect the unsorted part, we're done. */ + if (!full) + return false; + + /* Inspect the unsorted part. */ + for (i = 2 * ranges->nranges + ranges->nsorted; i < 2 * ranges->nranges + ranges->nvalues; i++) + { + Datum compar; + + compar = FunctionCall2Coll(cmpEqualFn, colloid, newval, ranges->values[i]); + + /* found an exact match */ + if (DatumGetBool(compar)) + return true; + } + + /* the value is not covered by this BRIN tuple */ + return false; +} + +/* + * Expand ranges from Ranges into ExpandedRange array. This expects the + * eranges to be pre-allocated and with the correct size - there needs to be + * (nranges + nvalues) elements. + * + * The order of expanded ranges is arbitrary. We do expand the ranges first, + * and this part is sorted. But then we expand the values, and this part may + * be unsorted. + */ +static void +fill_expanded_ranges(ExpandedRange *eranges, int neranges, Ranges *ranges) +{ + int idx; + int i; + + /* Check that the output array has the right size. */ + Assert(neranges == (ranges->nranges + ranges->nvalues)); + + idx = 0; + for (i = 0; i < ranges->nranges; i++) + { + eranges[idx].minval = ranges->values[2 * i]; + eranges[idx].maxval = ranges->values[2 * i + 1]; + eranges[idx].collapsed = false; + idx++; + + Assert(idx <= neranges); + } + + for (i = 0; i < ranges->nvalues; i++) + { + eranges[idx].minval = ranges->values[2 * ranges->nranges + i]; + eranges[idx].maxval = ranges->values[2 * ranges->nranges + i]; + eranges[idx].collapsed = true; + idx++; + + Assert(idx <= neranges); + } + + /* Did we produce the expected number of elements? */ + Assert(idx == neranges); + + return; +} + +/* + * Sort and deduplicate expanded ranges. + * + * The ranges may be deduplicated - we're simply appending values, without + * checking for duplicates etc. So maybe the deduplication will reduce the + * number of ranges enough, and we won't have to compute the distances etc. + * + * Returns the number of expanded ranges. + */ +static int +sort_expanded_ranges(FmgrInfo *cmp, Oid colloid, + ExpandedRange *eranges, int neranges) +{ + int n; + int i; + compare_context cxt; + + Assert(neranges > 0); + + /* sort the values */ + cxt.colloid = colloid; + cxt.cmpFn = cmp; + + /* + * XXX We do qsort on all the values, but we could also leverage the fact + * that some of the input data is already sorted (all the ranges and maybe + * some of the points) and do merge sort. + */ + qsort_arg(eranges, neranges, sizeof(ExpandedRange), + compare_expanded_ranges, &cxt); + + /* + * Deduplicate the ranges - simply compare each range to the preceding + * one, and skip the duplicate ones. + */ + n = 1; + for (i = 1; i < neranges; i++) + { + /* if the current range is equal to the preceding one, do nothing */ + if (!compare_expanded_ranges(&eranges[i - 1], &eranges[i], (void *) &cxt)) + continue; + + /* otherwise, copy it to n-th place (if not already there) */ + if (i != n) + memcpy(&eranges[n], &eranges[i], sizeof(ExpandedRange)); + + n++; + } + + Assert((n > 0) && (n <= neranges)); + + return n; +} + +/* + * When combining multiple Range values (in union function), some of the + * ranges may overlap. We simply merge the overlapping ranges to fix that. + * + * XXX This assumes the expanded ranges were previously sorted (by minval + * and then maxval). We leverage this when detecting overlap. + */ +static int +merge_overlapping_ranges(FmgrInfo *cmp, Oid colloid, + ExpandedRange *eranges, int neranges) +{ + int idx; + + /* Merge ranges (idx) and (idx+1) if they overlap. */ + idx = 0; + while (idx < (neranges - 1)) + { + Datum r; + + /* + * comparing [?,maxval] vs. [minval,?] - the ranges overlap if (minval + * < maxval) + */ + r = FunctionCall2Coll(cmp, colloid, + eranges[idx].maxval, + eranges[idx + 1].minval); + + /* + * Nope, maxval < minval, so no overlap. And we know the ranges are + * ordered, so there are no more overlaps, because all the remaining + * ranges have greater or equal minval. + */ + if (DatumGetBool(r)) + { + /* proceed to the next range */ + idx += 1; + continue; + } + + /* + * So ranges 'idx' and 'idx+1' do overlap, but we don't know if + * 'idx+1' is contained in 'idx', or if they overlap only partially. + * So compare the upper bounds and keep the larger one. + */ + r = FunctionCall2Coll(cmp, colloid, + eranges[idx].maxval, + eranges[idx + 1].maxval); + + if (DatumGetBool(r)) + eranges[idx].maxval = eranges[idx + 1].maxval; + + /* + * The range certainly is no longer collapsed (irrespectively of the + * previous state). + */ + eranges[idx].collapsed = false; + + /* + * Now get rid of the (idx+1) range entirely by shifting the remaining + * ranges by 1. There are neranges elements, and we need to move + * elements from (idx+2). That means the number of elements to move is + * [ncranges - (idx+2)]. + */ + memmove(&eranges[idx + 1], &eranges[idx + 2], + (neranges - (idx + 2)) * sizeof(ExpandedRange)); + + /* + * Decrease the number of ranges, and repeat (with the same range, as + * it might overlap with additional ranges thanks to the merge). + */ + neranges--; + } + + return neranges; +} + +/* + * Simple comparator for distance values, comparing the double value. + * This is intentionally sorting the distances in descending order, i.e. + * the longer gaps will be at the front. + */ +static int +compare_distances(const void *a, const void *b) +{ + DistanceValue *da = (DistanceValue *) a; + DistanceValue *db = (DistanceValue *) b; + + if (da->value < db->value) + return 1; + else if (da->value > db->value) + return -1; + + return 0; +} + +/* + * Given an array of expanded ranges, compute size of the gaps between each + * range. For neranges there are (neranges-1) gaps. + * + * We simply call the "distance" function to compute the (max-min) for pairs + * of consecutive ranges. The function may be fairly expensive, so we do that + * just once (and then use it to pick as many ranges to merge as possible). + * + * See reduce_expanded_ranges for details. + */ +static DistanceValue * +build_distances(FmgrInfo *distanceFn, Oid colloid, + ExpandedRange *eranges, int neranges) +{ + int i; + int ndistances; + DistanceValue *distances; + + Assert(neranges > 0); + + /* If there's only a single range, there's no distance to calculate. */ + if (neranges == 1) + return NULL; + + ndistances = (neranges - 1); + distances = (DistanceValue *) palloc0(sizeof(DistanceValue) * ndistances); + + /* + * Walk through the ranges once and compute the distance between the + * ranges so that we can sort them once. + */ + for (i = 0; i < ndistances; i++) + { + Datum a1, + a2, + r; + + a1 = eranges[i].maxval; + a2 = eranges[i + 1].minval; + + /* compute length of the gap (between max/min) */ + r = FunctionCall2Coll(distanceFn, colloid, a1, a2); + + /* remember the index of the gap the distance is for */ + distances[i].index = i; + distances[i].value = DatumGetFloat8(r); + } + + /* + * Sort the distances in descending order, so that the longest gaps are at + * the front. + */ + pg_qsort(distances, ndistances, sizeof(DistanceValue), compare_distances); + + return distances; +} + +/* + * Builds expanded ranges for the existing ranges (and single-point ranges), + * and also the new value (which did not fit into the array). This expanded + * representation makes the processing a bit easier, as it allows handling + * ranges and points the same way. + * + * We sort and deduplicate the expanded ranges - this is necessary, because + * the points may be unsorted. And moreover the two parts (ranges and + * points) are sorted on their own. + */ +static ExpandedRange * +build_expanded_ranges(FmgrInfo *cmp, Oid colloid, Ranges *ranges, + int *nranges) +{ + int neranges; + ExpandedRange *eranges; + + /* both ranges and points are expanded into a separate element */ + neranges = ranges->nranges + ranges->nvalues; + + eranges = (ExpandedRange *) palloc0(neranges * sizeof(ExpandedRange)); + + /* fill the expanded ranges */ + fill_expanded_ranges(eranges, neranges, ranges); + + /* sort and deduplicate the expanded ranges */ + neranges = sort_expanded_ranges(cmp, colloid, eranges, neranges); + + /* remember how many ranges we built */ + *nranges = neranges; + + return eranges; +} + +#ifdef USE_ASSERT_CHECKING +/* + * Counts boundary values needed to store the ranges. Each single-point + * range is stored using a single value, each regular range needs two. + */ +static int +count_values(ExpandedRange *cranges, int ncranges) +{ + int i; + int count; + + count = 0; + for (i = 0; i < ncranges; i++) + { + if (cranges[i].collapsed) + count += 1; + else + count += 2; + } + + return count; +} +#endif + +/* + * reduce_expanded_ranges + * reduce the ranges until the number of values is low enough + * + * Combines ranges until the number of boundary values drops below the + * threshold specified by max_values. This happens by merging enough + * ranges by the distance between them. + * + * Returns the number of result ranges. + * + * We simply use the global min/max and then add boundaries for enough + * largest gaps. Each gap adds 2 values, so we simply use (target/2-1) + * distances. Then we simply sort all the values - each two values are + * a boundary of a range (possibly collapsed). + * + * XXX Some of the ranges may be collapsed (i.e. the min/max values are + * equal), but we ignore that for now. We could repeat the process, + * adding a couple more gaps recursively. + * + * XXX The ranges to merge are selected solely using the distance. But + * that may not be the best strategy, for example when multiple gaps + * are of equal (or very similar) length. + * + * Consider for example points 1, 2, 3, .., 64, which have gaps of the + * same length 1 of course. In that case, we tend to pick the first + * gap of that length, which leads to this: + * + * step 1: [1, 2], 3, 4, 5, .., 64 + * step 2: [1, 3], 4, 5, .., 64 + * step 3: [1, 4], 5, .., 64 + * ... + * + * So in the end we'll have one "large" range and multiple small points. + * That may be fine, but it seems a bit strange and non-optimal. Maybe + * we should consider other things when picking ranges to merge - e.g. + * length of the ranges? Or perhaps randomize the choice of ranges, with + * probability inversely proportional to the distance (the gap lengths + * may be very close, but not exactly the same). + * + * XXX Or maybe we could just handle this by using random value as a + * tie-break, or by adding random noise to the actual distance. + */ +static int +reduce_expanded_ranges(ExpandedRange *eranges, int neranges, + DistanceValue *distances, int max_values, + FmgrInfo *cmp, Oid colloid) +{ + int i; + int nvalues; + Datum *values; + + compare_context cxt; + + /* total number of gaps between ranges */ + int ndistances = (neranges - 1); + + /* number of gaps to keep */ + int keep = (max_values / 2 - 1); + + /* + * Maybe we have a sufficiently low number of ranges already? + * + * XXX This should happen before we actually do the expensive stuff like + * sorting, so maybe this should be just an assert. + */ + if (keep >= ndistances) + return neranges; + + /* sort the values */ + cxt.colloid = colloid; + cxt.cmpFn = cmp; + + /* allocate space for the boundary values */ + nvalues = 0; + values = (Datum *) palloc(sizeof(Datum) * max_values); + + /* add the global min/max values, from the first/last range */ + values[nvalues++] = eranges[0].minval; + values[nvalues++] = eranges[neranges - 1].maxval; + + /* add boundary values for enough gaps */ + for (i = 0; i < keep; i++) + { + /* index of the gap between (index) and (index+1) ranges */ + int index = distances[i].index; + + Assert((index >= 0) && ((index + 1) < neranges)); + + /* add max from the preceding range, minval from the next one */ + values[nvalues++] = eranges[index].maxval; + values[nvalues++] = eranges[index + 1].minval; + + Assert(nvalues <= max_values); + } + + /* We should have an even number of range values. */ + Assert(nvalues % 2 == 0); + + /* + * Sort the values using the comparator function, and form ranges from the + * sorted result. + */ + qsort_arg(values, nvalues, sizeof(Datum), + compare_values, &cxt); + + /* We have nvalues boundary values, which means nvalues/2 ranges. */ + for (i = 0; i < (nvalues / 2); i++) + { + eranges[i].minval = values[2 * i]; + eranges[i].maxval = values[2 * i + 1]; + + /* if the boundary values are the same, it's a collapsed range */ + eranges[i].collapsed = (compare_values(&values[2 * i], + &values[2 * i + 1], + &cxt) == 0); + } + + return (nvalues / 2); +} + +/* + * Store the boundary values from ExpandedRanges back into 'ranges' (using + * only the minimal number of values needed). + */ +static void +store_expanded_ranges(Ranges *ranges, ExpandedRange *eranges, int neranges) +{ + int i; + int idx = 0; + + /* first copy in the regular ranges */ + ranges->nranges = 0; + for (i = 0; i < neranges; i++) + { + if (!eranges[i].collapsed) + { + ranges->values[idx++] = eranges[i].minval; + ranges->values[idx++] = eranges[i].maxval; + ranges->nranges++; + } + } + + /* now copy in the collapsed ones */ + ranges->nvalues = 0; + for (i = 0; i < neranges; i++) + { + if (eranges[i].collapsed) + { + ranges->values[idx++] = eranges[i].minval; + ranges->nvalues++; + } + } + + /* all the values are sorted */ + ranges->nsorted = ranges->nvalues; + + Assert(count_values(eranges, neranges) == 2 * ranges->nranges + ranges->nvalues); + Assert(2 * ranges->nranges + ranges->nvalues <= ranges->maxvalues); +} + + +/* + * Consider freeing space in the ranges. Checks if there's space for at least + * one new value, and performs compaction if needed. + * + * Returns true if the value was actually modified. + */ +static bool +ensure_free_space_in_buffer(BrinDesc *bdesc, Oid colloid, + AttrNumber attno, Form_pg_attribute attr, + Ranges *range) +{ + MemoryContext ctx; + MemoryContext oldctx; + + FmgrInfo *cmpFn, + *distanceFn; + + /* expanded ranges */ + ExpandedRange *eranges; + int neranges; + DistanceValue *distances; + + /* + * If there is free space in the buffer, we're done without having to + * modify anything. + */ + if (2 * range->nranges + range->nvalues < range->maxvalues) + return false; + + /* we'll certainly need the comparator, so just look it up now */ + cmpFn = minmax_multi_get_strategy_procinfo(bdesc, attno, attr->atttypid, + BTLessStrategyNumber); + + /* deduplicate values, if there's an unsorted part */ + range_deduplicate_values(range); + + /* + * Did we reduce enough free space by just the deduplication? + * + * We don't simply check against range->maxvalues again. The deduplication + * might have freed very little space (e.g. just one value), forcing us to + * do deduplication very often. In that case, it's better to do the + * compaction and reduce more space. + */ + if (2 * range->nranges + range->nvalues <= range->maxvalues * MINMAX_BUFFER_LOAD_FACTOR) + return true; + + /* + * We need to combine some of the existing ranges, to reduce the number of + * values we have to store. + * + * The distanceFn calls (which may internally call e.g. numeric_le) may + * allocate quite a bit of memory, and we must not leak it (we might have + * to do this repeatedly, even for a single BRIN page range). Otherwise + * we'd have problems e.g. when building new indexes. So we use a memory + * context and make sure we free the memory at the end (so if we call the + * distance function many times, it might be an issue, but meh). + */ + ctx = AllocSetContextCreate(CurrentMemoryContext, + "minmax-multi context", + ALLOCSET_DEFAULT_SIZES); + + oldctx = MemoryContextSwitchTo(ctx); + + /* build the expanded ranges */ + eranges = build_expanded_ranges(cmpFn, colloid, range, &neranges); + + /* and we'll also need the 'distance' procedure */ + distanceFn = minmax_multi_get_procinfo(bdesc, attno, PROCNUM_DISTANCE); + + /* build array of gap distances and sort them in ascending order */ + distances = build_distances(distanceFn, colloid, eranges, neranges); + + /* + * Combine ranges until we release at least 50% of the space. This + * threshold is somewhat arbitrary, perhaps needs tuning. We must not use + * too low or high value. + */ + neranges = reduce_expanded_ranges(eranges, neranges, distances, + range->maxvalues * MINMAX_BUFFER_LOAD_FACTOR, + cmpFn, colloid); + + /* Make sure we've sufficiently reduced the number of ranges. */ + Assert(count_values(eranges, neranges) <= range->maxvalues * MINMAX_BUFFER_LOAD_FACTOR); + + /* decompose the expanded ranges into regular ranges and single values */ + store_expanded_ranges(range, eranges, neranges); + + MemoryContextSwitchTo(oldctx); + MemoryContextDelete(ctx); + + /* Did we break the ranges somehow? */ + AssertCheckRanges(range, cmpFn, colloid); + + return true; +} + +/* + * range_add_value + * Add the new value to the minmax-multi range. + */ +static bool +range_add_value(BrinDesc *bdesc, Oid colloid, + AttrNumber attno, Form_pg_attribute attr, + Ranges *ranges, Datum newval) +{ + FmgrInfo *cmpFn; + bool modified = false; + + /* we'll certainly need the comparator, so just look it up now */ + cmpFn = minmax_multi_get_strategy_procinfo(bdesc, attno, attr->atttypid, + BTLessStrategyNumber); + + /* comprehensive checks of the input ranges */ + AssertCheckRanges(ranges, cmpFn, colloid); + + /* + * Make sure there's enough free space in the buffer. We only trigger this + * when the buffer is full, which means it had to be modified as we size + * it to be larger than what is stored on disk. + * + * This needs to happen before we check if the value is contained in the + * range, because the value might be in the unsorted part, and we don't + * check that in range_contains_value. The deduplication would then move + * it to the sorted part, and we'd add the value too, which violates the + * rule that we never have duplicates with the ranges or sorted values. + * + * We might also deduplicate and recheck if the value is contained, but + * that seems like overkill. We'd need to deduplicate anyway, so why not + * do it now. + */ + modified = ensure_free_space_in_buffer(bdesc, colloid, + attno, attr, ranges); + + /* + * Bail out if the value already is covered by the range. + * + * We could also add values until we hit values_per_range, and then do the + * deduplication in a batch, hoping for better efficiency. But that would + * mean we actually modify the range every time, which means having to + * serialize the value, which does palloc, walks the values, copies them, + * etc. Not exactly cheap. + * + * So instead we do the check, which should be fairly cheap - assuming the + * comparator function is not very expensive. + * + * This also implies the values array can't contain duplicate values. + */ + if (range_contains_value(bdesc, colloid, attno, attr, ranges, newval, false)) + return modified; + + /* Make a copy of the value, if needed. */ + newval = datumCopy(newval, attr->attbyval, attr->attlen); + + /* + * If there's space in the values array, copy it in and we're done. + * + * We do want to keep the values sorted (to speed up searches), so we do a + * simple insertion sort. We could do something more elaborate, e.g. by + * sorting the values only now and then, but for small counts (e.g. when + * maxvalues is 64) this should be fine. + */ + ranges->values[2 * ranges->nranges + ranges->nvalues] = newval; + ranges->nvalues++; + + /* If we added the first value, we can consider it as sorted. */ + if (ranges->nvalues == 1) + ranges->nsorted = 1; + + /* + * Check we haven't broken the ordering of boundary values (checks both + * parts, but that doesn't hurt). + */ + AssertCheckRanges(ranges, cmpFn, colloid); + + /* Check the range contains the value we just added. */ + Assert(range_contains_value(bdesc, colloid, attno, attr, ranges, newval, true)); + + /* yep, we've modified the range */ + return true; +} + +/* + * Generate range representation of data collected during "batch mode". + * This is similar to reduce_expanded_ranges, except that we can't assume + * the values are sorted and there may be duplicate values. + */ +static void +compactify_ranges(BrinDesc *bdesc, Ranges *ranges, int max_values) +{ + FmgrInfo *cmpFn, + *distanceFn; + + /* expanded ranges */ + ExpandedRange *eranges; + int neranges; + DistanceValue *distances; + + MemoryContext ctx; + MemoryContext oldctx; + + /* + * Do we need to actually compactify anything? + * + * There are two reasons why compaction may be needed - firstly, there may + * be too many values, or some of the values may be unsorted. + */ + if ((ranges->nranges * 2 + ranges->nvalues <= max_values) && + (ranges->nsorted == ranges->nvalues)) + return; + + /* we'll certainly need the comparator, so just look it up now */ + cmpFn = minmax_multi_get_strategy_procinfo(bdesc, ranges->attno, ranges->typid, + BTLessStrategyNumber); + + /* and we'll also need the 'distance' procedure */ + distanceFn = minmax_multi_get_procinfo(bdesc, ranges->attno, PROCNUM_DISTANCE); + + /* + * The distanceFn calls (which may internally call e.g. numeric_le) may + * allocate quite a bit of memory, and we must not leak it. Otherwise, + * we'd have problems e.g. when building indexes. So we create a local + * memory context and make sure we free the memory before leaving this + * function (not after every call). + */ + ctx = AllocSetContextCreate(CurrentMemoryContext, + "minmax-multi context", + ALLOCSET_DEFAULT_SIZES); + + oldctx = MemoryContextSwitchTo(ctx); + + /* build the expanded ranges */ + eranges = build_expanded_ranges(cmpFn, ranges->colloid, ranges, &neranges); + + /* build array of gap distances and sort them in ascending order */ + distances = build_distances(distanceFn, ranges->colloid, + eranges, neranges); + + /* + * Combine ranges until we get below max_values. We don't use any scale + * factor, because this is used during serialization, and we don't expect + * more tuples to be inserted anytime soon. + */ + neranges = reduce_expanded_ranges(eranges, neranges, distances, + max_values, cmpFn, ranges->colloid); + + Assert(count_values(eranges, neranges) <= max_values); + + /* transform back into regular ranges and single values */ + store_expanded_ranges(ranges, eranges, neranges); + + /* check all the range invariants */ + AssertCheckRanges(ranges, cmpFn, ranges->colloid); + + MemoryContextSwitchTo(oldctx); + MemoryContextDelete(ctx); +} + +Datum +brin_minmax_multi_opcinfo(PG_FUNCTION_ARGS) +{ + BrinOpcInfo *result; + + /* + * opaque->strategy_procinfos is initialized lazily; here it is set to + * all-uninitialized by palloc0 which sets fn_oid to InvalidOid. + */ + + result = palloc0(MAXALIGN(SizeofBrinOpcInfo(1)) + + sizeof(MinmaxMultiOpaque)); + result->oi_nstored = 1; + result->oi_regular_nulls = true; + result->oi_opaque = (MinmaxMultiOpaque *) + MAXALIGN((char *) result + SizeofBrinOpcInfo(1)); + result->oi_typcache[0] = lookup_type_cache(PG_BRIN_MINMAX_MULTI_SUMMARYOID, 0); + + PG_RETURN_POINTER(result); +} + +/* + * Compute the distance between two float4 values (plain subtraction). + */ +Datum +brin_minmax_multi_distance_float4(PG_FUNCTION_ARGS) +{ + float a1 = PG_GETARG_FLOAT4(0); + float a2 = PG_GETARG_FLOAT4(1); + + /* if both values are NaN, then we consider them the same */ + if (isnan(a1) && isnan(a2)) + PG_RETURN_FLOAT8(0.0); + + /* if one value is NaN, use infinite distance */ + if (isnan(a1) || isnan(a2)) + PG_RETURN_FLOAT8(get_float8_infinity()); + + /* + * We know the values are range boundaries, but the range may be collapsed + * (i.e. single points), with equal values. + */ + Assert(a1 <= a2); + + PG_RETURN_FLOAT8((double) a2 - (double) a1); +} + +/* + * Compute the distance between two float8 values (plain subtraction). + */ +Datum +brin_minmax_multi_distance_float8(PG_FUNCTION_ARGS) +{ + double a1 = PG_GETARG_FLOAT8(0); + double a2 = PG_GETARG_FLOAT8(1); + + /* if both values are NaN, then we consider them the same */ + if (isnan(a1) && isnan(a2)) + PG_RETURN_FLOAT8(0.0); + + /* if one value is NaN, use infinite distance */ + if (isnan(a1) || isnan(a2)) + PG_RETURN_FLOAT8(get_float8_infinity()); + + /* + * We know the values are range boundaries, but the range may be collapsed + * (i.e. single points), with equal values. + */ + Assert(a1 <= a2); + + PG_RETURN_FLOAT8(a2 - a1); +} + +/* + * Compute the distance between two int2 values (plain subtraction). + */ +Datum +brin_minmax_multi_distance_int2(PG_FUNCTION_ARGS) +{ + int16 a1 = PG_GETARG_INT16(0); + int16 a2 = PG_GETARG_INT16(1); + + /* + * We know the values are range boundaries, but the range may be collapsed + * (i.e. single points), with equal values. + */ + Assert(a1 <= a2); + + PG_RETURN_FLOAT8((double) a2 - (double) a1); +} + +/* + * Compute the distance between two int4 values (plain subtraction). + */ +Datum +brin_minmax_multi_distance_int4(PG_FUNCTION_ARGS) +{ + int32 a1 = PG_GETARG_INT32(0); + int32 a2 = PG_GETARG_INT32(1); + + /* + * We know the values are range boundaries, but the range may be collapsed + * (i.e. single points), with equal values. + */ + Assert(a1 <= a2); + + PG_RETURN_FLOAT8((double) a2 - (double) a1); +} + +/* + * Compute the distance between two int8 values (plain subtraction). + */ +Datum +brin_minmax_multi_distance_int8(PG_FUNCTION_ARGS) +{ + int64 a1 = PG_GETARG_INT64(0); + int64 a2 = PG_GETARG_INT64(1); + + /* + * We know the values are range boundaries, but the range may be collapsed + * (i.e. single points), with equal values. + */ + Assert(a1 <= a2); + + PG_RETURN_FLOAT8((double) a2 - (double) a1); +} + +/* + * Compute the distance between two tid values (by mapping them to float8 and + * then subtracting them). + */ +Datum +brin_minmax_multi_distance_tid(PG_FUNCTION_ARGS) +{ + double da1, + da2; + + ItemPointer pa1 = (ItemPointer) PG_GETARG_DATUM(0); + ItemPointer pa2 = (ItemPointer) PG_GETARG_DATUM(1); + + /* + * We know the values are range boundaries, but the range may be collapsed + * (i.e. single points), with equal values. + */ + Assert(ItemPointerCompare(pa1, pa2) <= 0); + + /* + * We use the no-check variants here, because user-supplied values may + * have (ip_posid == 0). See ItemPointerCompare. + */ + da1 = ItemPointerGetBlockNumberNoCheck(pa1) * MaxHeapTuplesPerPage + + ItemPointerGetOffsetNumberNoCheck(pa1); + + da2 = ItemPointerGetBlockNumberNoCheck(pa2) * MaxHeapTuplesPerPage + + ItemPointerGetOffsetNumberNoCheck(pa2); + + PG_RETURN_FLOAT8(da2 - da1); +} + +/* + * Compute the distance between two numeric values (plain subtraction). + */ +Datum +brin_minmax_multi_distance_numeric(PG_FUNCTION_ARGS) +{ + Datum d; + Datum a1 = PG_GETARG_DATUM(0); + Datum a2 = PG_GETARG_DATUM(1); + + /* + * We know the values are range boundaries, but the range may be collapsed + * (i.e. single points), with equal values. + */ + Assert(DatumGetBool(DirectFunctionCall2(numeric_le, a1, a2))); + + d = DirectFunctionCall2(numeric_sub, a2, a1); /* a2 - a1 */ + + PG_RETURN_FLOAT8(DirectFunctionCall1(numeric_float8, d)); +} + +/* + * Compute the approximate distance between two UUID values. + * + * XXX We do not need a perfectly accurate value, so we approximate the + * deltas (which would have to be 128-bit integers) with a 64-bit float. + * The small inaccuracies do not matter in practice, in the worst case + * we'll decide to merge ranges that are not the closest ones. + */ +Datum +brin_minmax_multi_distance_uuid(PG_FUNCTION_ARGS) +{ + int i; + float8 delta = 0; + + Datum a1 = PG_GETARG_DATUM(0); + Datum a2 = PG_GETARG_DATUM(1); + + pg_uuid_t *u1 = DatumGetUUIDP(a1); + pg_uuid_t *u2 = DatumGetUUIDP(a2); + + /* + * We know the values are range boundaries, but the range may be collapsed + * (i.e. single points), with equal values. + */ + Assert(DatumGetBool(DirectFunctionCall2(uuid_le, a1, a2))); + + /* compute approximate delta as a double precision value */ + for (i = UUID_LEN - 1; i >= 0; i--) + { + delta += (int) u2->data[i] - (int) u1->data[i]; + delta /= 256; + } + + Assert(delta >= 0); + + PG_RETURN_FLOAT8(delta); +} + +/* + * Compute the approximate distance between two dates. + */ +Datum +brin_minmax_multi_distance_date(PG_FUNCTION_ARGS) +{ + float8 delta = 0; + DateADT dateVal1 = PG_GETARG_DATEADT(0); + DateADT dateVal2 = PG_GETARG_DATEADT(1); + + delta = (float8) dateVal2 - (float8) dateVal1; + + Assert(delta >= 0); + + PG_RETURN_FLOAT8(delta); +} + +/* + * Compute the approximate distance between two time (without tz) values. + * + * TimeADT is just an int64, so we simply subtract the values directly. + */ +Datum +brin_minmax_multi_distance_time(PG_FUNCTION_ARGS) +{ + float8 delta = 0; + + TimeADT ta = PG_GETARG_TIMEADT(0); + TimeADT tb = PG_GETARG_TIMEADT(1); + + delta = (tb - ta); + + Assert(delta >= 0); + + PG_RETURN_FLOAT8(delta); +} + +/* + * Compute the approximate distance between two timetz values. + * + * Simply subtracts the TimeADT (int64) values embedded in TimeTzADT. + */ +Datum +brin_minmax_multi_distance_timetz(PG_FUNCTION_ARGS) +{ + float8 delta = 0; + + TimeTzADT *ta = PG_GETARG_TIMETZADT_P(0); + TimeTzADT *tb = PG_GETARG_TIMETZADT_P(1); + + delta = (tb->time - ta->time) + (tb->zone - ta->zone) * USECS_PER_SEC; + + Assert(delta >= 0); + + PG_RETURN_FLOAT8(delta); +} + +/* + * Compute the distance between two timestamp values. + */ +Datum +brin_minmax_multi_distance_timestamp(PG_FUNCTION_ARGS) +{ + float8 delta = 0; + + Timestamp dt1 = PG_GETARG_TIMESTAMP(0); + Timestamp dt2 = PG_GETARG_TIMESTAMP(1); + + delta = (float8) dt2 - (float8) dt1; + + Assert(delta >= 0); + + PG_RETURN_FLOAT8(delta); +} + +/* + * Compute the distance between two interval values. + */ +Datum +brin_minmax_multi_distance_interval(PG_FUNCTION_ARGS) +{ + float8 delta = 0; + + Interval *ia = PG_GETARG_INTERVAL_P(0); + Interval *ib = PG_GETARG_INTERVAL_P(1); + + int64 dayfraction; + int64 days; + + /* + * Delta is (fractional) number of days between the intervals. Assume + * months have 30 days for consistency with interval_cmp_internal. We + * don't need to be exact, in the worst case we'll build a bit less + * efficient ranges. But we should not contradict interval_cmp. + */ + dayfraction = (ib->time % USECS_PER_DAY) - (ia->time % USECS_PER_DAY); + days = (ib->time / USECS_PER_DAY) - (ia->time / USECS_PER_DAY); + days += (int64) ib->day - (int64) ia->day; + days += ((int64) ib->month - (int64) ia->month) * INT64CONST(30); + + /* convert to double precision */ + delta = (double) days + dayfraction / (double) USECS_PER_DAY; + + Assert(delta >= 0); + + PG_RETURN_FLOAT8(delta); +} + +/* + * Compute the distance between two pg_lsn values. + * + * LSN is just an int64 encoding position in the stream, so just subtract + * those int64 values directly. + */ +Datum +brin_minmax_multi_distance_pg_lsn(PG_FUNCTION_ARGS) +{ + float8 delta = 0; + + XLogRecPtr lsna = PG_GETARG_LSN(0); + XLogRecPtr lsnb = PG_GETARG_LSN(1); + + delta = (lsnb - lsna); + + Assert(delta >= 0); + + PG_RETURN_FLOAT8(delta); +} + +/* + * Compute the distance between two macaddr values. + * + * mac addresses are treated as 6 unsigned chars, so do the same thing we + * already do for UUID values. + */ +Datum +brin_minmax_multi_distance_macaddr(PG_FUNCTION_ARGS) +{ + float8 delta; + + macaddr *a = PG_GETARG_MACADDR_P(0); + macaddr *b = PG_GETARG_MACADDR_P(1); + + delta = ((float8) b->f - (float8) a->f); + delta /= 256; + + delta += ((float8) b->e - (float8) a->e); + delta /= 256; + + delta += ((float8) b->d - (float8) a->d); + delta /= 256; + + delta += ((float8) b->c - (float8) a->c); + delta /= 256; + + delta += ((float8) b->b - (float8) a->b); + delta /= 256; + + delta += ((float8) b->a - (float8) a->a); + delta /= 256; + + Assert(delta >= 0); + + PG_RETURN_FLOAT8(delta); +} + +/* + * Compute the distance between two macaddr8 values. + * + * macaddr8 addresses are 8 unsigned chars, so do the same thing we + * already do for UUID values. + */ +Datum +brin_minmax_multi_distance_macaddr8(PG_FUNCTION_ARGS) +{ + float8 delta; + + macaddr8 *a = PG_GETARG_MACADDR8_P(0); + macaddr8 *b = PG_GETARG_MACADDR8_P(1); + + delta = ((float8) b->h - (float8) a->h); + delta /= 256; + + delta += ((float8) b->g - (float8) a->g); + delta /= 256; + + delta += ((float8) b->f - (float8) a->f); + delta /= 256; + + delta += ((float8) b->e - (float8) a->e); + delta /= 256; + + delta += ((float8) b->d - (float8) a->d); + delta /= 256; + + delta += ((float8) b->c - (float8) a->c); + delta /= 256; + + delta += ((float8) b->b - (float8) a->b); + delta /= 256; + + delta += ((float8) b->a - (float8) a->a); + delta /= 256; + + Assert(delta >= 0); + + PG_RETURN_FLOAT8(delta); +} + +/* + * Compute the distance between two inet values. + * + * The distance is defined as the difference between 32-bit/128-bit values, + * depending on the IP version. The distance is computed by subtracting + * the bytes and normalizing it to [0,1] range for each IP family. + * Addresses from different families are considered to be in maximum + * distance, which is 1.0. + * + * XXX Does this need to consider the mask (bits)? For now, it's ignored. + */ +Datum +brin_minmax_multi_distance_inet(PG_FUNCTION_ARGS) +{ + float8 delta; + int i; + int len; + unsigned char *addra, + *addrb; + + inet *ipa = PG_GETARG_INET_PP(0); + inet *ipb = PG_GETARG_INET_PP(1); + + int lena, + lenb; + + /* + * If the addresses are from different families, consider them to be in + * maximal possible distance (which is 1.0). + */ + if (ip_family(ipa) != ip_family(ipb)) + PG_RETURN_FLOAT8(1.0); + + addra = (unsigned char *) palloc(ip_addrsize(ipa)); + memcpy(addra, ip_addr(ipa), ip_addrsize(ipa)); + + addrb = (unsigned char *) palloc(ip_addrsize(ipb)); + memcpy(addrb, ip_addr(ipb), ip_addrsize(ipb)); + + /* + * The length is calculated from the mask length, because we sort the + * addresses by first address in the range, so A.B.C.D/24 < A.B.C.1 (the + * first range starts at A.B.C.0, which is before A.B.C.1). We don't want + * to produce a negative delta in this case, so we just cut the extra + * bytes. + * + * XXX Maybe this should be a bit more careful and cut the bits, not just + * whole bytes. + */ + lena = ip_bits(ipa); + lenb = ip_bits(ipb); + + len = ip_addrsize(ipa); + + /* apply the network mask to both addresses */ + for (i = 0; i < len; i++) + { + unsigned char mask; + int nbits; + + nbits = Max(0, lena - (i * 8)); + if (nbits < 8) + { + mask = (0xFF << (8 - nbits)); + addra[i] = (addra[i] & mask); + } + + nbits = Max(0, lenb - (i * 8)); + if (nbits < 8) + { + mask = (0xFF << (8 - nbits)); + addrb[i] = (addrb[i] & mask); + } + } + + /* Calculate the difference between the addresses. */ + delta = 0; + for (i = len - 1; i >= 0; i--) + { + unsigned char a = addra[i]; + unsigned char b = addrb[i]; + + delta += (float8) b - (float8) a; + delta /= 256; + } + + Assert((delta >= 0) && (delta <= 1)); + + pfree(addra); + pfree(addrb); + + PG_RETURN_FLOAT8(delta); +} + +static void +brin_minmax_multi_serialize(BrinDesc *bdesc, Datum src, Datum *dst) +{ + Ranges *ranges = (Ranges *) DatumGetPointer(src); + SerializedRanges *s; + + /* + * In batch mode, we need to compress the accumulated values to the + * actually requested number of values/ranges. + */ + compactify_ranges(bdesc, ranges, ranges->target_maxvalues); + + /* At this point everything has to be fully sorted. */ + Assert(ranges->nsorted == ranges->nvalues); + + s = brin_range_serialize(ranges); + dst[0] = PointerGetDatum(s); +} + +static int +brin_minmax_multi_get_values(BrinDesc *bdesc, MinMaxMultiOptions *opts) +{ + return MinMaxMultiGetValuesPerRange(opts); +} + +/* + * Examine the given index tuple (which contains the partial status of a + * certain page range) by comparing it to the given value that comes from + * another heap tuple. If the new value is outside the min/max range + * specified by the existing tuple values, update the index tuple and return + * true. Otherwise, return false and do not modify in this case. + */ +Datum +brin_minmax_multi_add_value(PG_FUNCTION_ARGS) +{ + BrinDesc *bdesc = (BrinDesc *) PG_GETARG_POINTER(0); + BrinValues *column = (BrinValues *) PG_GETARG_POINTER(1); + Datum newval = PG_GETARG_DATUM(2); + bool isnull PG_USED_FOR_ASSERTS_ONLY = PG_GETARG_DATUM(3); + MinMaxMultiOptions *opts = (MinMaxMultiOptions *) PG_GET_OPCLASS_OPTIONS(); + Oid colloid = PG_GET_COLLATION(); + bool modified = false; + Form_pg_attribute attr; + AttrNumber attno; + Ranges *ranges; + SerializedRanges *serialized = NULL; + + Assert(!isnull); + + attno = column->bv_attno; + attr = TupleDescAttr(bdesc->bd_tupdesc, attno - 1); + + /* use the already deserialized value, if possible */ + ranges = (Ranges *) DatumGetPointer(column->bv_mem_value); + + /* + * If this is the first non-null value, we need to initialize the range + * list. Otherwise, just extract the existing range list from BrinValues. + * + * When starting with an empty range, we assume this is a batch mode and + * we use a larger buffer. The buffer size is derived from the BRIN range + * size, number of rows per page, with some sensible min/max values. A + * small buffer would be bad for performance, but a large buffer might + * require a lot of memory (because of keeping all the values). + */ + if (column->bv_allnulls) + { + MemoryContext oldctx; + + int target_maxvalues; + int maxvalues; + BlockNumber pagesPerRange = BrinGetPagesPerRange(bdesc->bd_index); + + /* what was specified as a reloption? */ + target_maxvalues = brin_minmax_multi_get_values(bdesc, opts); + + /* + * Determine the insert buffer size - we use 10x the target, capped to + * the maximum number of values in the heap range. This is more than + * enough, considering the actual number of rows per page is likely + * much lower, but meh. + */ + maxvalues = Min(target_maxvalues * MINMAX_BUFFER_FACTOR, + MaxHeapTuplesPerPage * pagesPerRange); + + /* but always at least the original value */ + maxvalues = Max(maxvalues, target_maxvalues); + + /* always cap by MIN/MAX */ + maxvalues = Max(maxvalues, MINMAX_BUFFER_MIN); + maxvalues = Min(maxvalues, MINMAX_BUFFER_MAX); + + oldctx = MemoryContextSwitchTo(column->bv_context); + ranges = minmax_multi_init(maxvalues); + ranges->attno = attno; + ranges->colloid = colloid; + ranges->typid = attr->atttypid; + ranges->target_maxvalues = target_maxvalues; + + /* we'll certainly need the comparator, so just look it up now */ + ranges->cmp = minmax_multi_get_strategy_procinfo(bdesc, attno, attr->atttypid, + BTLessStrategyNumber); + + MemoryContextSwitchTo(oldctx); + + column->bv_allnulls = false; + modified = true; + + column->bv_mem_value = PointerGetDatum(ranges); + column->bv_serialize = brin_minmax_multi_serialize; + } + else if (!ranges) + { + MemoryContext oldctx; + + int maxvalues; + BlockNumber pagesPerRange = BrinGetPagesPerRange(bdesc->bd_index); + + oldctx = MemoryContextSwitchTo(column->bv_context); + + serialized = (SerializedRanges *) PG_DETOAST_DATUM(column->bv_values[0]); + + /* + * Determine the insert buffer size - we use 10x the target, capped to + * the maximum number of values in the heap range. This is more than + * enough, considering the actual number of rows per page is likely + * much lower, but meh. + */ + maxvalues = Min(serialized->maxvalues * MINMAX_BUFFER_FACTOR, + MaxHeapTuplesPerPage * pagesPerRange); + + /* but always at least the original value */ + maxvalues = Max(maxvalues, serialized->maxvalues); + + /* always cap by MIN/MAX */ + maxvalues = Max(maxvalues, MINMAX_BUFFER_MIN); + maxvalues = Min(maxvalues, MINMAX_BUFFER_MAX); + + ranges = brin_range_deserialize(maxvalues, serialized); + + ranges->attno = attno; + ranges->colloid = colloid; + ranges->typid = attr->atttypid; + + /* we'll certainly need the comparator, so just look it up now */ + ranges->cmp = minmax_multi_get_strategy_procinfo(bdesc, attno, attr->atttypid, + BTLessStrategyNumber); + + column->bv_mem_value = PointerGetDatum(ranges); + column->bv_serialize = brin_minmax_multi_serialize; + + MemoryContextSwitchTo(oldctx); + } + + /* + * Try to add the new value to the range. We need to update the modified + * flag, so that we serialize the updated summary later. + */ + modified |= range_add_value(bdesc, colloid, attno, attr, ranges, newval); + + + PG_RETURN_BOOL(modified); +} + +/* + * Given an index tuple corresponding to a certain page range and a scan key, + * return whether the scan key is consistent with the index tuple's min/max + * values. Return true if so, false otherwise. + */ +Datum +brin_minmax_multi_consistent(PG_FUNCTION_ARGS) +{ + BrinDesc *bdesc = (BrinDesc *) PG_GETARG_POINTER(0); + BrinValues *column = (BrinValues *) PG_GETARG_POINTER(1); + ScanKey *keys = (ScanKey *) PG_GETARG_POINTER(2); + int nkeys = PG_GETARG_INT32(3); + + Oid colloid = PG_GET_COLLATION(), + subtype; + AttrNumber attno; + Datum value; + FmgrInfo *finfo; + SerializedRanges *serialized; + Ranges *ranges; + int keyno; + int rangeno; + int i; + + attno = column->bv_attno; + + serialized = (SerializedRanges *) PG_DETOAST_DATUM(column->bv_values[0]); + ranges = brin_range_deserialize(serialized->maxvalues, serialized); + + /* inspect the ranges, and for each one evaluate the scan keys */ + for (rangeno = 0; rangeno < ranges->nranges; rangeno++) + { + Datum minval = ranges->values[2 * rangeno]; + Datum maxval = ranges->values[2 * rangeno + 1]; + + /* assume the range is matching, and we'll try to prove otherwise */ + bool matching = true; + + for (keyno = 0; keyno < nkeys; keyno++) + { + Datum matches; + ScanKey key = keys[keyno]; + + /* NULL keys are handled and filtered-out in bringetbitmap */ + Assert(!(key->sk_flags & SK_ISNULL)); + + attno = key->sk_attno; + subtype = key->sk_subtype; + value = key->sk_argument; + switch (key->sk_strategy) + { + case BTLessStrategyNumber: + case BTLessEqualStrategyNumber: + finfo = minmax_multi_get_strategy_procinfo(bdesc, attno, subtype, + key->sk_strategy); + /* first value from the array */ + matches = FunctionCall2Coll(finfo, colloid, minval, value); + break; + + case BTEqualStrategyNumber: + { + Datum compar; + FmgrInfo *cmpFn; + + /* by default this range does not match */ + matches = false; + + /* + * Otherwise, need to compare the new value with + * boundaries of all the ranges. First check if it's + * less than the absolute minimum, which is the first + * value in the array. + */ + cmpFn = minmax_multi_get_strategy_procinfo(bdesc, attno, subtype, + BTGreaterStrategyNumber); + compar = FunctionCall2Coll(cmpFn, colloid, minval, value); + + /* smaller than the smallest value in this range */ + if (DatumGetBool(compar)) + break; + + cmpFn = minmax_multi_get_strategy_procinfo(bdesc, attno, subtype, + BTLessStrategyNumber); + compar = FunctionCall2Coll(cmpFn, colloid, maxval, value); + + /* larger than the largest value in this range */ + if (DatumGetBool(compar)) + break; + + /* + * We haven't managed to eliminate this range, so + * consider it matching. + */ + matches = true; + + break; + } + case BTGreaterEqualStrategyNumber: + case BTGreaterStrategyNumber: + finfo = minmax_multi_get_strategy_procinfo(bdesc, attno, subtype, + key->sk_strategy); + /* last value from the array */ + matches = FunctionCall2Coll(finfo, colloid, maxval, value); + break; + + default: + /* shouldn't happen */ + elog(ERROR, "invalid strategy number %d", key->sk_strategy); + matches = 0; + break; + } + + /* the range has to match all the scan keys */ + matching &= DatumGetBool(matches); + + /* once we find a non-matching key, we're done */ + if (!matching) + break; + } + + /* + * have we found a range matching all scan keys? if yes, we're done + */ + if (matching) + PG_RETURN_DATUM(BoolGetDatum(true)); + } + + /* + * And now inspect the values. We don't bother with doing a binary search + * here, because we're dealing with serialized / fully compacted ranges, + * so there should be only very few values. + */ + for (i = 0; i < ranges->nvalues; i++) + { + Datum val = ranges->values[2 * ranges->nranges + i]; + + /* assume the range is matching, and we'll try to prove otherwise */ + bool matching = true; + + for (keyno = 0; keyno < nkeys; keyno++) + { + Datum matches; + ScanKey key = keys[keyno]; + + /* we've already dealt with NULL keys at the beginning */ + if (key->sk_flags & SK_ISNULL) + continue; + + attno = key->sk_attno; + subtype = key->sk_subtype; + value = key->sk_argument; + switch (key->sk_strategy) + { + case BTLessStrategyNumber: + case BTLessEqualStrategyNumber: + case BTEqualStrategyNumber: + case BTGreaterEqualStrategyNumber: + case BTGreaterStrategyNumber: + + finfo = minmax_multi_get_strategy_procinfo(bdesc, attno, subtype, + key->sk_strategy); + matches = FunctionCall2Coll(finfo, colloid, val, value); + break; + + default: + /* shouldn't happen */ + elog(ERROR, "invalid strategy number %d", key->sk_strategy); + matches = 0; + break; + } + + /* the range has to match all the scan keys */ + matching &= DatumGetBool(matches); + + /* once we find a non-matching key, we're done */ + if (!matching) + break; + } + + /* have we found a range matching all scan keys? if yes, we're done */ + if (matching) + PG_RETURN_DATUM(BoolGetDatum(true)); + } + + PG_RETURN_DATUM(BoolGetDatum(false)); +} + +/* + * Given two BrinValues, update the first of them as a union of the summary + * values contained in both. The second one is untouched. + */ +Datum +brin_minmax_multi_union(PG_FUNCTION_ARGS) +{ + BrinDesc *bdesc = (BrinDesc *) PG_GETARG_POINTER(0); + BrinValues *col_a = (BrinValues *) PG_GETARG_POINTER(1); + BrinValues *col_b = (BrinValues *) PG_GETARG_POINTER(2); + + Oid colloid = PG_GET_COLLATION(); + SerializedRanges *serialized_a; + SerializedRanges *serialized_b; + Ranges *ranges_a; + Ranges *ranges_b; + AttrNumber attno; + Form_pg_attribute attr; + ExpandedRange *eranges; + int neranges; + FmgrInfo *cmpFn, + *distanceFn; + DistanceValue *distances; + MemoryContext ctx; + MemoryContext oldctx; + + Assert(col_a->bv_attno == col_b->bv_attno); + Assert(!col_a->bv_allnulls && !col_b->bv_allnulls); + + attno = col_a->bv_attno; + attr = TupleDescAttr(bdesc->bd_tupdesc, attno - 1); + + serialized_a = (SerializedRanges *) PG_DETOAST_DATUM(col_a->bv_values[0]); + serialized_b = (SerializedRanges *) PG_DETOAST_DATUM(col_b->bv_values[0]); + + ranges_a = brin_range_deserialize(serialized_a->maxvalues, serialized_a); + ranges_b = brin_range_deserialize(serialized_b->maxvalues, serialized_b); + + /* make sure neither of the ranges is NULL */ + Assert(ranges_a && ranges_b); + + neranges = (ranges_a->nranges + ranges_a->nvalues) + + (ranges_b->nranges + ranges_b->nvalues); + + /* + * The distanceFn calls (which may internally call e.g. numeric_le) may + * allocate quite a bit of memory, and we must not leak it. Otherwise, + * we'd have problems e.g. when building indexes. So we create a local + * memory context and make sure we free the memory before leaving this + * function (not after every call). + */ + ctx = AllocSetContextCreate(CurrentMemoryContext, + "minmax-multi context", + ALLOCSET_DEFAULT_SIZES); + + oldctx = MemoryContextSwitchTo(ctx); + + /* allocate and fill */ + eranges = (ExpandedRange *) palloc0(neranges * sizeof(ExpandedRange)); + + /* fill the expanded ranges with entries for the first range */ + fill_expanded_ranges(eranges, ranges_a->nranges + ranges_a->nvalues, + ranges_a); + + /* and now add combine ranges for the second range */ + fill_expanded_ranges(&eranges[ranges_a->nranges + ranges_a->nvalues], + ranges_b->nranges + ranges_b->nvalues, + ranges_b); + + cmpFn = minmax_multi_get_strategy_procinfo(bdesc, attno, attr->atttypid, + BTLessStrategyNumber); + + /* sort the expanded ranges */ + neranges = sort_expanded_ranges(cmpFn, colloid, eranges, neranges); + + /* + * We've loaded two different lists of expanded ranges, so some of them + * may be overlapping. So walk through them and merge them. + */ + neranges = merge_overlapping_ranges(cmpFn, colloid, eranges, neranges); + + /* check that the combine ranges are correct (no overlaps, ordering) */ + AssertCheckExpandedRanges(bdesc, colloid, attno, attr, eranges, neranges); + + /* + * If needed, reduce some of the ranges. + * + * XXX This may be fairly expensive, so maybe we should do it only when + * it's actually needed (when we have too many ranges). + */ + + /* build array of gap distances and sort them in ascending order */ + distanceFn = minmax_multi_get_procinfo(bdesc, attno, PROCNUM_DISTANCE); + distances = build_distances(distanceFn, colloid, eranges, neranges); + + /* + * See how many values would be needed to store the current ranges, and if + * needed combine as many of them to get below the threshold. The + * collapsed ranges will be stored as a single value. + * + * XXX This does not apply the load factor, as we don't expect to add more + * values to the range, so we prefer to keep as many ranges as possible. + * + * XXX Can the maxvalues be different in the two ranges? Perhaps we should + * use maximum of those? + */ + neranges = reduce_expanded_ranges(eranges, neranges, distances, + ranges_a->maxvalues, + cmpFn, colloid); + + /* update the first range summary */ + store_expanded_ranges(ranges_a, eranges, neranges); + + MemoryContextSwitchTo(oldctx); + MemoryContextDelete(ctx); + + /* cleanup and update the serialized value */ + pfree(serialized_a); + col_a->bv_values[0] = PointerGetDatum(brin_range_serialize(ranges_a)); + + PG_RETURN_VOID(); +} + +/* + * Cache and return minmax multi opclass support procedure + * + * Return the procedure corresponding to the given function support number + * or null if it does not exist. + */ +static FmgrInfo * +minmax_multi_get_procinfo(BrinDesc *bdesc, uint16 attno, uint16 procnum) +{ + MinmaxMultiOpaque *opaque; + uint16 basenum = procnum - PROCNUM_BASE; + + /* + * We cache these in the opaque struct, to avoid repetitive syscache + * lookups. + */ + opaque = (MinmaxMultiOpaque *) bdesc->bd_info[attno - 1]->oi_opaque; + + /* + * If we already searched for this proc and didn't find it, don't bother + * searching again. + */ + if (opaque->extra_proc_missing[basenum]) + return NULL; + + if (opaque->extra_procinfos[basenum].fn_oid == InvalidOid) + { + if (RegProcedureIsValid(index_getprocid(bdesc->bd_index, attno, + procnum))) + { + fmgr_info_copy(&opaque->extra_procinfos[basenum], + index_getprocinfo(bdesc->bd_index, attno, procnum), + bdesc->bd_context); + } + else + { + opaque->extra_proc_missing[basenum] = true; + return NULL; + } + } + + return &opaque->extra_procinfos[basenum]; +} + +/* + * Cache and return the procedure for the given strategy. + * + * Note: this function mirrors minmax_multi_get_strategy_procinfo; see notes + * there. If changes are made here, see that function too. + */ +static FmgrInfo * +minmax_multi_get_strategy_procinfo(BrinDesc *bdesc, uint16 attno, Oid subtype, + uint16 strategynum) +{ + MinmaxMultiOpaque *opaque; + + Assert(strategynum >= 1 && + strategynum <= BTMaxStrategyNumber); + + opaque = (MinmaxMultiOpaque *) bdesc->bd_info[attno - 1]->oi_opaque; + + /* + * We cache the procedures for the previous subtype in the opaque struct, + * to avoid repetitive syscache lookups. If the subtype changed, + * invalidate all the cached entries. + */ + if (opaque->cached_subtype != subtype) + { + uint16 i; + + for (i = 1; i <= BTMaxStrategyNumber; i++) + opaque->strategy_procinfos[i - 1].fn_oid = InvalidOid; + opaque->cached_subtype = subtype; + } + + if (opaque->strategy_procinfos[strategynum - 1].fn_oid == InvalidOid) + { + Form_pg_attribute attr; + HeapTuple tuple; + Oid opfamily, + oprid; + + opfamily = bdesc->bd_index->rd_opfamily[attno - 1]; + attr = TupleDescAttr(bdesc->bd_tupdesc, attno - 1); + tuple = SearchSysCache4(AMOPSTRATEGY, ObjectIdGetDatum(opfamily), + ObjectIdGetDatum(attr->atttypid), + ObjectIdGetDatum(subtype), + Int16GetDatum(strategynum)); + if (!HeapTupleIsValid(tuple)) + elog(ERROR, "missing operator %d(%u,%u) in opfamily %u", + strategynum, attr->atttypid, subtype, opfamily); + + oprid = DatumGetObjectId(SysCacheGetAttrNotNull(AMOPSTRATEGY, tuple, + Anum_pg_amop_amopopr)); + ReleaseSysCache(tuple); + Assert(RegProcedureIsValid(oprid)); + + fmgr_info_cxt(get_opcode(oprid), + &opaque->strategy_procinfos[strategynum - 1], + bdesc->bd_context); + } + + return &opaque->strategy_procinfos[strategynum - 1]; +} + +Datum +brin_minmax_multi_options(PG_FUNCTION_ARGS) +{ + local_relopts *relopts = (local_relopts *) PG_GETARG_POINTER(0); + + init_local_reloptions(relopts, sizeof(MinMaxMultiOptions)); + + add_local_int_reloption(relopts, "values_per_range", "desc", + MINMAX_MULTI_DEFAULT_VALUES_PER_PAGE, 8, 256, + offsetof(MinMaxMultiOptions, valuesPerRange)); + + PG_RETURN_VOID(); +} + +/* + * brin_minmax_multi_summary_in + * - input routine for type brin_minmax_multi_summary. + * + * brin_minmax_multi_summary is only used internally to represent summaries + * in BRIN minmax-multi indexes, so it has no operations of its own, and we + * disallow input too. + */ +Datum +brin_minmax_multi_summary_in(PG_FUNCTION_ARGS) +{ + /* + * brin_minmax_multi_summary stores the data in binary form and parsing + * text input is not needed, so disallow this. + */ + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cannot accept a value of type %s", "brin_minmax_multi_summary"))); + + PG_RETURN_VOID(); /* keep compiler quiet */ +} + + +/* + * brin_minmax_multi_summary_out + * - output routine for type brin_minmax_multi_summary. + * + * BRIN minmax-multi summaries are serialized into a bytea value, but we + * want to output something nicer humans can understand. + */ +Datum +brin_minmax_multi_summary_out(PG_FUNCTION_ARGS) +{ + int i; + int idx; + SerializedRanges *ranges; + Ranges *ranges_deserialized; + StringInfoData str; + bool isvarlena; + Oid outfunc; + FmgrInfo fmgrinfo; + ArrayBuildState *astate_values = NULL; + + initStringInfo(&str); + appendStringInfoChar(&str, '{'); + + /* + * Detoast to get value with full 4B header (can't be stored in a toast + * table, but can use 1B header). + */ + ranges = (SerializedRanges *) PG_DETOAST_DATUM_PACKED(PG_GETARG_DATUM(0)); + + /* lookup output func for the type */ + getTypeOutputInfo(ranges->typid, &outfunc, &isvarlena); + fmgr_info(outfunc, &fmgrinfo); + + /* deserialize the range info easy-to-process pieces */ + ranges_deserialized = brin_range_deserialize(ranges->maxvalues, ranges); + + appendStringInfo(&str, "nranges: %d nvalues: %d maxvalues: %d", + ranges_deserialized->nranges, + ranges_deserialized->nvalues, + ranges_deserialized->maxvalues); + + /* serialize ranges */ + idx = 0; + for (i = 0; i < ranges_deserialized->nranges; i++) + { + char *a, + *b; + text *c; + StringInfoData buf; + + initStringInfo(&buf); + + a = OutputFunctionCall(&fmgrinfo, ranges_deserialized->values[idx++]); + b = OutputFunctionCall(&fmgrinfo, ranges_deserialized->values[idx++]); + + appendStringInfo(&buf, "%s ... %s", a, b); + + c = cstring_to_text_with_len(buf.data, buf.len); + + astate_values = accumArrayResult(astate_values, + PointerGetDatum(c), + false, + TEXTOID, + CurrentMemoryContext); + } + + if (ranges_deserialized->nranges > 0) + { + Oid typoutput; + bool typIsVarlena; + Datum val; + char *extval; + + getTypeOutputInfo(ANYARRAYOID, &typoutput, &typIsVarlena); + + val = makeArrayResult(astate_values, CurrentMemoryContext); + + extval = OidOutputFunctionCall(typoutput, val); + + appendStringInfo(&str, " ranges: %s", extval); + } + + /* serialize individual values */ + astate_values = NULL; + + for (i = 0; i < ranges_deserialized->nvalues; i++) + { + Datum a; + text *b; + + a = FunctionCall1(&fmgrinfo, ranges_deserialized->values[idx++]); + b = cstring_to_text(DatumGetCString(a)); + + astate_values = accumArrayResult(astate_values, + PointerGetDatum(b), + false, + TEXTOID, + CurrentMemoryContext); + } + + if (ranges_deserialized->nvalues > 0) + { + Oid typoutput; + bool typIsVarlena; + Datum val; + char *extval; + + getTypeOutputInfo(ANYARRAYOID, &typoutput, &typIsVarlena); + + val = makeArrayResult(astate_values, CurrentMemoryContext); + + extval = OidOutputFunctionCall(typoutput, val); + + appendStringInfo(&str, " values: %s", extval); + } + + + appendStringInfoChar(&str, '}'); + + PG_RETURN_CSTRING(str.data); +} + +/* + * brin_minmax_multi_summary_recv + * - binary input routine for type brin_minmax_multi_summary. + */ +Datum +brin_minmax_multi_summary_recv(PG_FUNCTION_ARGS) +{ + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cannot accept a value of type %s", "brin_minmax_multi_summary"))); + + PG_RETURN_VOID(); /* keep compiler quiet */ +} + +/* + * brin_minmax_multi_summary_send + * - binary output routine for type brin_minmax_multi_summary. + * + * BRIN minmax-multi summaries are serialized in a bytea value (although + * the type is named differently), so let's just send that. + */ +Datum +brin_minmax_multi_summary_send(PG_FUNCTION_ARGS) +{ + return byteasend(fcinfo); +} |