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Diffstat (limited to 'contrib/pageinspect/btreefuncs.c')
| -rw-r--r-- | contrib/pageinspect/btreefuncs.c | 793 |
1 files changed, 793 insertions, 0 deletions
diff --git a/contrib/pageinspect/btreefuncs.c b/contrib/pageinspect/btreefuncs.c new file mode 100644 index 0000000..62f2c1b --- /dev/null +++ b/contrib/pageinspect/btreefuncs.c @@ -0,0 +1,793 @@ +/* + * contrib/pageinspect/btreefuncs.c + * + * + * btreefuncs.c + * + * Copyright (c) 2006 Satoshi Nagayasu <nagayasus@nttdata.co.jp> + * + * Permission to use, copy, modify, and distribute this software and + * its documentation for any purpose, without fee, and without a + * written agreement is hereby granted, provided that the above + * copyright notice and this paragraph and the following two + * paragraphs appear in all copies. + * + * IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT, + * INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING + * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS + * DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED + * OF THE POSSIBILITY OF SUCH DAMAGE. + * + * THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS + * IS" BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, + * SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. + */ + +#include "postgres.h" + +#include "access/nbtree.h" +#include "access/relation.h" +#include "catalog/namespace.h" +#include "catalog/pg_am.h" +#include "catalog/pg_type.h" +#include "funcapi.h" +#include "miscadmin.h" +#include "pageinspect.h" +#include "utils/array.h" +#include "utils/builtins.h" +#include "utils/rel.h" +#include "utils/varlena.h" + +PG_FUNCTION_INFO_V1(bt_metap); +PG_FUNCTION_INFO_V1(bt_page_items_1_9); +PG_FUNCTION_INFO_V1(bt_page_items); +PG_FUNCTION_INFO_V1(bt_page_items_bytea); +PG_FUNCTION_INFO_V1(bt_page_stats_1_9); +PG_FUNCTION_INFO_V1(bt_page_stats); + +#define IS_INDEX(r) ((r)->rd_rel->relkind == RELKIND_INDEX) +#define IS_BTREE(r) ((r)->rd_rel->relam == BTREE_AM_OID) +#define DatumGetItemPointer(X) ((ItemPointer) DatumGetPointer(X)) +#define ItemPointerGetDatum(X) PointerGetDatum(X) + +/* note: BlockNumber is unsigned, hence can't be negative */ +#define CHECK_RELATION_BLOCK_RANGE(rel, blkno) { \ + if ( RelationGetNumberOfBlocks(rel) <= (BlockNumber) (blkno) ) \ + elog(ERROR, "block number out of range"); } + +/* ------------------------------------------------ + * structure for single btree page statistics + * ------------------------------------------------ + */ +typedef struct BTPageStat +{ + uint32 blkno; + uint32 live_items; + uint32 dead_items; + uint32 page_size; + uint32 max_avail; + uint32 free_size; + uint32 avg_item_size; + char type; + + /* opaque data */ + BlockNumber btpo_prev; + BlockNumber btpo_next; + uint32 btpo_level; + uint16 btpo_flags; + BTCycleId btpo_cycleid; +} BTPageStat; + + +/* ------------------------------------------------- + * GetBTPageStatistics() + * + * Collect statistics of single b-tree page + * ------------------------------------------------- + */ +static void +GetBTPageStatistics(BlockNumber blkno, Buffer buffer, BTPageStat *stat) +{ + Page page = BufferGetPage(buffer); + PageHeader phdr = (PageHeader) page; + OffsetNumber maxoff = PageGetMaxOffsetNumber(page); + BTPageOpaque opaque = BTPageGetOpaque(page); + int item_size = 0; + int off; + + stat->blkno = blkno; + + stat->max_avail = BLCKSZ - (BLCKSZ - phdr->pd_special + SizeOfPageHeaderData); + + stat->dead_items = stat->live_items = 0; + + stat->page_size = PageGetPageSize(page); + + /* page type (flags) */ + if (P_ISDELETED(opaque)) + { + /* We divide deleted pages into leaf ('d') or internal ('D') */ + if (P_ISLEAF(opaque) || !P_HAS_FULLXID(opaque)) + stat->type = 'd'; + else + stat->type = 'D'; + + /* + * Report safexid in a deleted page. + * + * Handle pg_upgrade'd deleted pages that used the previous safexid + * representation in btpo_level field (this used to be a union type + * called "bpto"). + */ + if (P_HAS_FULLXID(opaque)) + { + FullTransactionId safexid = BTPageGetDeleteXid(page); + + elog(DEBUG2, "deleted page from block %u has safexid %u:%u", + blkno, EpochFromFullTransactionId(safexid), + XidFromFullTransactionId(safexid)); + } + else + elog(DEBUG2, "deleted page from block %u has safexid %u", + blkno, opaque->btpo_level); + + /* Don't interpret BTDeletedPageData as index tuples */ + maxoff = InvalidOffsetNumber; + } + else if (P_IGNORE(opaque)) + stat->type = 'e'; + else if (P_ISLEAF(opaque)) + stat->type = 'l'; + else if (P_ISROOT(opaque)) + stat->type = 'r'; + else + stat->type = 'i'; + + /* btpage opaque data */ + stat->btpo_prev = opaque->btpo_prev; + stat->btpo_next = opaque->btpo_next; + stat->btpo_level = opaque->btpo_level; + stat->btpo_flags = opaque->btpo_flags; + stat->btpo_cycleid = opaque->btpo_cycleid; + + /* count live and dead tuples, and free space */ + for (off = FirstOffsetNumber; off <= maxoff; off++) + { + IndexTuple itup; + + ItemId id = PageGetItemId(page, off); + + itup = (IndexTuple) PageGetItem(page, id); + + item_size += IndexTupleSize(itup); + + if (!ItemIdIsDead(id)) + stat->live_items++; + else + stat->dead_items++; + } + stat->free_size = PageGetFreeSpace(page); + + if ((stat->live_items + stat->dead_items) > 0) + stat->avg_item_size = item_size / (stat->live_items + stat->dead_items); + else + stat->avg_item_size = 0; +} + +/* ----------------------------------------------- + * bt_page_stats() + * + * Usage: SELECT * FROM bt_page_stats('t1_pkey', 1); + * ----------------------------------------------- + */ +static Datum +bt_page_stats_internal(PG_FUNCTION_ARGS, enum pageinspect_version ext_version) +{ + text *relname = PG_GETARG_TEXT_PP(0); + int64 blkno = (ext_version == PAGEINSPECT_V1_8 ? PG_GETARG_UINT32(1) : PG_GETARG_INT64(1)); + Buffer buffer; + Relation rel; + RangeVar *relrv; + Datum result; + HeapTuple tuple; + TupleDesc tupleDesc; + int j; + char *values[11]; + BTPageStat stat; + + if (!superuser()) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + errmsg("must be superuser to use pageinspect functions"))); + + relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname)); + rel = relation_openrv(relrv, AccessShareLock); + + if (!IS_INDEX(rel) || !IS_BTREE(rel)) + ereport(ERROR, + (errcode(ERRCODE_WRONG_OBJECT_TYPE), + errmsg("\"%s\" is not a %s index", + RelationGetRelationName(rel), "btree"))); + + /* + * Reject attempts to read non-local temporary relations; we would be + * likely to get wrong data since we have no visibility into the owning + * session's local buffers. + */ + if (RELATION_IS_OTHER_TEMP(rel)) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cannot access temporary tables of other sessions"))); + + if (blkno < 0 || blkno > MaxBlockNumber) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("invalid block number"))); + + if (blkno == 0) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("block 0 is a meta page"))); + + CHECK_RELATION_BLOCK_RANGE(rel, blkno); + + buffer = ReadBuffer(rel, blkno); + LockBuffer(buffer, BUFFER_LOCK_SHARE); + + /* keep compiler quiet */ + stat.btpo_prev = stat.btpo_next = InvalidBlockNumber; + stat.btpo_flags = stat.free_size = stat.avg_item_size = 0; + + GetBTPageStatistics(blkno, buffer, &stat); + + UnlockReleaseBuffer(buffer); + relation_close(rel, AccessShareLock); + + /* Build a tuple descriptor for our result type */ + if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE) + elog(ERROR, "return type must be a row type"); + + j = 0; + values[j++] = psprintf("%u", stat.blkno); + values[j++] = psprintf("%c", stat.type); + values[j++] = psprintf("%u", stat.live_items); + values[j++] = psprintf("%u", stat.dead_items); + values[j++] = psprintf("%u", stat.avg_item_size); + values[j++] = psprintf("%u", stat.page_size); + values[j++] = psprintf("%u", stat.free_size); + values[j++] = psprintf("%u", stat.btpo_prev); + values[j++] = psprintf("%u", stat.btpo_next); + values[j++] = psprintf("%u", stat.btpo_level); + values[j++] = psprintf("%d", stat.btpo_flags); + + tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc), + values); + + result = HeapTupleGetDatum(tuple); + + PG_RETURN_DATUM(result); +} + +Datum +bt_page_stats_1_9(PG_FUNCTION_ARGS) +{ + return bt_page_stats_internal(fcinfo, PAGEINSPECT_V1_9); +} + +/* entry point for old extension version */ +Datum +bt_page_stats(PG_FUNCTION_ARGS) +{ + return bt_page_stats_internal(fcinfo, PAGEINSPECT_V1_8); +} + + +/* + * cross-call data structure for SRF + */ +struct user_args +{ + Page page; + OffsetNumber offset; + bool leafpage; + bool rightmost; + TupleDesc tupd; +}; + +/*------------------------------------------------------- + * bt_page_print_tuples() + * + * Form a tuple describing index tuple at a given offset + * ------------------------------------------------------ + */ +static Datum +bt_page_print_tuples(struct user_args *uargs) +{ + Page page = uargs->page; + OffsetNumber offset = uargs->offset; + bool leafpage = uargs->leafpage; + bool rightmost = uargs->rightmost; + bool ispivottuple; + Datum values[9]; + bool nulls[9]; + HeapTuple tuple; + ItemId id; + IndexTuple itup; + int j; + int off; + int dlen; + char *dump, + *datacstring; + char *ptr; + ItemPointer htid; + + id = PageGetItemId(page, offset); + + if (!ItemIdIsValid(id)) + elog(ERROR, "invalid ItemId"); + + itup = (IndexTuple) PageGetItem(page, id); + + j = 0; + memset(nulls, 0, sizeof(nulls)); + values[j++] = DatumGetInt16(offset); + values[j++] = ItemPointerGetDatum(&itup->t_tid); + values[j++] = Int32GetDatum((int) IndexTupleSize(itup)); + values[j++] = BoolGetDatum(IndexTupleHasNulls(itup)); + values[j++] = BoolGetDatum(IndexTupleHasVarwidths(itup)); + + ptr = (char *) itup + IndexInfoFindDataOffset(itup->t_info); + dlen = IndexTupleSize(itup) - IndexInfoFindDataOffset(itup->t_info); + + /* + * Make sure that "data" column does not include posting list or pivot + * tuple representation of heap TID(s). + * + * Note: BTreeTupleIsPivot() won't work reliably on !heapkeyspace indexes + * (those built before BTREE_VERSION 4), but we have no way of determining + * if this page came from a !heapkeyspace index. We may only have a bytea + * nbtree page image to go on, so in general there is no metapage that we + * can check. + * + * That's okay here because BTreeTupleIsPivot() can only return false for + * a !heapkeyspace pivot, never true for a !heapkeyspace non-pivot. Since + * heap TID isn't part of the keyspace in a !heapkeyspace index anyway, + * there cannot possibly be a pivot tuple heap TID representation that we + * fail to make an adjustment for. A !heapkeyspace index can have + * BTreeTupleIsPivot() return true (due to things like suffix truncation + * for INCLUDE indexes in Postgres v11), but when that happens + * BTreeTupleGetHeapTID() can be trusted to work reliably (i.e. return + * NULL). + * + * Note: BTreeTupleIsPosting() always works reliably, even with + * !heapkeyspace indexes. + */ + if (BTreeTupleIsPosting(itup)) + dlen -= IndexTupleSize(itup) - BTreeTupleGetPostingOffset(itup); + else if (BTreeTupleIsPivot(itup) && BTreeTupleGetHeapTID(itup) != NULL) + dlen -= MAXALIGN(sizeof(ItemPointerData)); + + if (dlen < 0 || dlen > INDEX_SIZE_MASK) + elog(ERROR, "invalid tuple length %d for tuple at offset number %u", + dlen, offset); + dump = palloc0(dlen * 3 + 1); + datacstring = dump; + for (off = 0; off < dlen; off++) + { + if (off > 0) + *dump++ = ' '; + sprintf(dump, "%02x", *(ptr + off) & 0xff); + dump += 2; + } + values[j++] = CStringGetTextDatum(datacstring); + pfree(datacstring); + + /* + * We need to work around the BTreeTupleIsPivot() !heapkeyspace limitation + * again. Deduce whether or not tuple must be a pivot tuple based on + * whether or not the page is a leaf page, as well as the page offset + * number of the tuple. + */ + ispivottuple = (!leafpage || (!rightmost && offset == P_HIKEY)); + + /* LP_DEAD bit can never be set for pivot tuples, so show a NULL there */ + if (!ispivottuple) + values[j++] = BoolGetDatum(ItemIdIsDead(id)); + else + { + Assert(!ItemIdIsDead(id)); + nulls[j++] = true; + } + + htid = BTreeTupleGetHeapTID(itup); + if (ispivottuple && !BTreeTupleIsPivot(itup)) + { + /* Don't show bogus heap TID in !heapkeyspace pivot tuple */ + htid = NULL; + } + + if (htid) + values[j++] = ItemPointerGetDatum(htid); + else + nulls[j++] = true; + + if (BTreeTupleIsPosting(itup)) + { + /* Build an array of item pointers */ + ItemPointer tids; + Datum *tids_datum; + int nposting; + + tids = BTreeTupleGetPosting(itup); + nposting = BTreeTupleGetNPosting(itup); + tids_datum = (Datum *) palloc(nposting * sizeof(Datum)); + for (int i = 0; i < nposting; i++) + tids_datum[i] = ItemPointerGetDatum(&tids[i]); + values[j++] = PointerGetDatum(construct_array(tids_datum, + nposting, + TIDOID, + sizeof(ItemPointerData), + false, TYPALIGN_SHORT)); + pfree(tids_datum); + } + else + nulls[j++] = true; + + /* Build and return the result tuple */ + tuple = heap_form_tuple(uargs->tupd, values, nulls); + + return HeapTupleGetDatum(tuple); +} + +/*------------------------------------------------------- + * bt_page_items() + * + * Get IndexTupleData set in a btree page + * + * Usage: SELECT * FROM bt_page_items('t1_pkey', 1); + *------------------------------------------------------- + */ +static Datum +bt_page_items_internal(PG_FUNCTION_ARGS, enum pageinspect_version ext_version) +{ + text *relname = PG_GETARG_TEXT_PP(0); + int64 blkno = (ext_version == PAGEINSPECT_V1_8 ? PG_GETARG_UINT32(1) : PG_GETARG_INT64(1)); + Datum result; + FuncCallContext *fctx; + MemoryContext mctx; + struct user_args *uargs; + + if (!superuser()) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + errmsg("must be superuser to use pageinspect functions"))); + + if (SRF_IS_FIRSTCALL()) + { + RangeVar *relrv; + Relation rel; + Buffer buffer; + BTPageOpaque opaque; + TupleDesc tupleDesc; + + fctx = SRF_FIRSTCALL_INIT(); + + relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname)); + rel = relation_openrv(relrv, AccessShareLock); + + if (!IS_INDEX(rel) || !IS_BTREE(rel)) + ereport(ERROR, + (errcode(ERRCODE_WRONG_OBJECT_TYPE), + errmsg("\"%s\" is not a %s index", + RelationGetRelationName(rel), "btree"))); + + /* + * Reject attempts to read non-local temporary relations; we would be + * likely to get wrong data since we have no visibility into the + * owning session's local buffers. + */ + if (RELATION_IS_OTHER_TEMP(rel)) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cannot access temporary tables of other sessions"))); + + if (blkno < 0 || blkno > MaxBlockNumber) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("invalid block number"))); + + if (blkno == 0) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("block 0 is a meta page"))); + + CHECK_RELATION_BLOCK_RANGE(rel, blkno); + + buffer = ReadBuffer(rel, blkno); + LockBuffer(buffer, BUFFER_LOCK_SHARE); + + /* + * We copy the page into local storage to avoid holding pin on the + * buffer longer than we must, and possibly failing to release it at + * all if the calling query doesn't fetch all rows. + */ + mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx); + + uargs = palloc(sizeof(struct user_args)); + + uargs->page = palloc(BLCKSZ); + memcpy(uargs->page, BufferGetPage(buffer), BLCKSZ); + + UnlockReleaseBuffer(buffer); + relation_close(rel, AccessShareLock); + + uargs->offset = FirstOffsetNumber; + + opaque = BTPageGetOpaque(uargs->page); + + if (!P_ISDELETED(opaque)) + fctx->max_calls = PageGetMaxOffsetNumber(uargs->page); + else + { + /* Don't interpret BTDeletedPageData as index tuples */ + elog(NOTICE, "page from block " INT64_FORMAT " is deleted", blkno); + fctx->max_calls = 0; + } + uargs->leafpage = P_ISLEAF(opaque); + uargs->rightmost = P_RIGHTMOST(opaque); + + /* Build a tuple descriptor for our result type */ + if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE) + elog(ERROR, "return type must be a row type"); + tupleDesc = BlessTupleDesc(tupleDesc); + + uargs->tupd = tupleDesc; + + fctx->user_fctx = uargs; + + MemoryContextSwitchTo(mctx); + } + + fctx = SRF_PERCALL_SETUP(); + uargs = fctx->user_fctx; + + if (fctx->call_cntr < fctx->max_calls) + { + result = bt_page_print_tuples(uargs); + uargs->offset++; + SRF_RETURN_NEXT(fctx, result); + } + + SRF_RETURN_DONE(fctx); +} + +Datum +bt_page_items_1_9(PG_FUNCTION_ARGS) +{ + return bt_page_items_internal(fcinfo, PAGEINSPECT_V1_9); +} + +/* entry point for old extension version */ +Datum +bt_page_items(PG_FUNCTION_ARGS) +{ + return bt_page_items_internal(fcinfo, PAGEINSPECT_V1_8); +} + +/*------------------------------------------------------- + * bt_page_items_bytea() + * + * Get IndexTupleData set in a btree page + * + * Usage: SELECT * FROM bt_page_items(get_raw_page('t1_pkey', 1)); + *------------------------------------------------------- + */ + +Datum +bt_page_items_bytea(PG_FUNCTION_ARGS) +{ + bytea *raw_page = PG_GETARG_BYTEA_P(0); + Datum result; + FuncCallContext *fctx; + struct user_args *uargs; + + if (!superuser()) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + errmsg("must be superuser to use raw page functions"))); + + if (SRF_IS_FIRSTCALL()) + { + BTPageOpaque opaque; + MemoryContext mctx; + TupleDesc tupleDesc; + + fctx = SRF_FIRSTCALL_INIT(); + mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx); + + uargs = palloc(sizeof(struct user_args)); + + uargs->page = get_page_from_raw(raw_page); + + if (PageIsNew(uargs->page)) + { + MemoryContextSwitchTo(mctx); + PG_RETURN_NULL(); + } + + uargs->offset = FirstOffsetNumber; + + /* verify the special space has the expected size */ + if (PageGetSpecialSize(uargs->page) != MAXALIGN(sizeof(BTPageOpaqueData))) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("input page is not a valid %s page", "btree"), + errdetail("Expected special size %d, got %d.", + (int) MAXALIGN(sizeof(BTPageOpaqueData)), + (int) PageGetSpecialSize(uargs->page)))); + + opaque = BTPageGetOpaque(uargs->page); + + if (P_ISMETA(opaque)) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("block is a meta page"))); + + if (P_ISLEAF(opaque) && opaque->btpo_level != 0) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("block is not a valid btree leaf page"))); + + if (P_ISDELETED(opaque)) + elog(NOTICE, "page is deleted"); + + if (!P_ISDELETED(opaque)) + fctx->max_calls = PageGetMaxOffsetNumber(uargs->page); + else + { + /* Don't interpret BTDeletedPageData as index tuples */ + elog(NOTICE, "page from block is deleted"); + fctx->max_calls = 0; + } + uargs->leafpage = P_ISLEAF(opaque); + uargs->rightmost = P_RIGHTMOST(opaque); + + /* Build a tuple descriptor for our result type */ + if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE) + elog(ERROR, "return type must be a row type"); + tupleDesc = BlessTupleDesc(tupleDesc); + + uargs->tupd = tupleDesc; + + fctx->user_fctx = uargs; + + MemoryContextSwitchTo(mctx); + } + + fctx = SRF_PERCALL_SETUP(); + uargs = fctx->user_fctx; + + if (fctx->call_cntr < fctx->max_calls) + { + result = bt_page_print_tuples(uargs); + uargs->offset++; + SRF_RETURN_NEXT(fctx, result); + } + + SRF_RETURN_DONE(fctx); +} + +/* Number of output arguments (columns) for bt_metap() */ +#define BT_METAP_COLS_V1_8 9 + +/* ------------------------------------------------ + * bt_metap() + * + * Get a btree's meta-page information + * + * Usage: SELECT * FROM bt_metap('t1_pkey') + * ------------------------------------------------ + */ +Datum +bt_metap(PG_FUNCTION_ARGS) +{ + text *relname = PG_GETARG_TEXT_PP(0); + Datum result; + Relation rel; + RangeVar *relrv; + BTMetaPageData *metad; + TupleDesc tupleDesc; + int j; + char *values[9]; + Buffer buffer; + Page page; + HeapTuple tuple; + + if (!superuser()) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + errmsg("must be superuser to use pageinspect functions"))); + + relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname)); + rel = relation_openrv(relrv, AccessShareLock); + + if (!IS_INDEX(rel) || !IS_BTREE(rel)) + ereport(ERROR, + (errcode(ERRCODE_WRONG_OBJECT_TYPE), + errmsg("\"%s\" is not a %s index", + RelationGetRelationName(rel), "btree"))); + + /* + * Reject attempts to read non-local temporary relations; we would be + * likely to get wrong data since we have no visibility into the owning + * session's local buffers. + */ + if (RELATION_IS_OTHER_TEMP(rel)) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cannot access temporary tables of other sessions"))); + + buffer = ReadBuffer(rel, 0); + LockBuffer(buffer, BUFFER_LOCK_SHARE); + + page = BufferGetPage(buffer); + metad = BTPageGetMeta(page); + + /* Build a tuple descriptor for our result type */ + if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE) + elog(ERROR, "return type must be a row type"); + + /* + * We need a kluge here to detect API versions prior to 1.8. Earlier + * versions incorrectly used int4 for certain columns. + * + * There is no way to reliably avoid the problems created by the old + * function definition at this point, so insist that the user update the + * extension. + */ + if (tupleDesc->natts < BT_METAP_COLS_V1_8) + ereport(ERROR, + (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION), + errmsg("function has wrong number of declared columns"), + errhint("To resolve the problem, update the \"pageinspect\" extension to the latest version."))); + + j = 0; + values[j++] = psprintf("%d", metad->btm_magic); + values[j++] = psprintf("%d", metad->btm_version); + values[j++] = psprintf(INT64_FORMAT, (int64) metad->btm_root); + values[j++] = psprintf(INT64_FORMAT, (int64) metad->btm_level); + values[j++] = psprintf(INT64_FORMAT, (int64) metad->btm_fastroot); + values[j++] = psprintf(INT64_FORMAT, (int64) metad->btm_fastlevel); + + /* + * Get values of extended metadata if available, use default values + * otherwise. Note that we rely on the assumption that btm_allequalimage + * is initialized to zero with indexes that were built on versions prior + * to Postgres 13 (just like _bt_metaversion()). + */ + if (metad->btm_version >= BTREE_NOVAC_VERSION) + { + values[j++] = psprintf(INT64_FORMAT, + (int64) metad->btm_last_cleanup_num_delpages); + values[j++] = psprintf("%f", metad->btm_last_cleanup_num_heap_tuples); + values[j++] = metad->btm_allequalimage ? "t" : "f"; + } + else + { + values[j++] = "0"; + values[j++] = "-1"; + values[j++] = "f"; + } + + tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc), + values); + + result = HeapTupleGetDatum(tuple); + + UnlockReleaseBuffer(buffer); + relation_close(rel, AccessShareLock); + + PG_RETURN_DATUM(result); +} |