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-rw-r--r--contrib/pageinspect/hashfuncs.c586
1 files changed, 586 insertions, 0 deletions
diff --git a/contrib/pageinspect/hashfuncs.c b/contrib/pageinspect/hashfuncs.c
new file mode 100644
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+++ b/contrib/pageinspect/hashfuncs.c
@@ -0,0 +1,586 @@
+/*
+ * hashfuncs.c
+ * Functions to investigate the content of HASH indexes
+ *
+ * Copyright (c) 2017-2021, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ * contrib/pageinspect/hashfuncs.c
+ */
+
+#include "postgres.h"
+
+#include "access/hash.h"
+#include "access/htup_details.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"
+
+PG_FUNCTION_INFO_V1(hash_page_type);
+PG_FUNCTION_INFO_V1(hash_page_stats);
+PG_FUNCTION_INFO_V1(hash_page_items);
+PG_FUNCTION_INFO_V1(hash_bitmap_info);
+PG_FUNCTION_INFO_V1(hash_metapage_info);
+
+#define IS_HASH(r) ((r)->rd_rel->relam == HASH_AM_OID)
+
+/* ------------------------------------------------
+ * structure for single hash page statistics
+ * ------------------------------------------------
+ */
+typedef struct HashPageStat
+{
+ int live_items;
+ int dead_items;
+ int page_size;
+ int free_size;
+
+ /* opaque data */
+ BlockNumber hasho_prevblkno;
+ BlockNumber hasho_nextblkno;
+ Bucket hasho_bucket;
+ uint16 hasho_flag;
+ uint16 hasho_page_id;
+} HashPageStat;
+
+
+/*
+ * Verify that the given bytea contains a HASH page, or die in the attempt.
+ * A pointer to a palloc'd, properly aligned copy of the page is returned.
+ */
+static Page
+verify_hash_page(bytea *raw_page, int flags)
+{
+ Page page = get_page_from_raw(raw_page);
+ int pagetype = LH_UNUSED_PAGE;
+
+ /* Treat new pages as unused. */
+ if (!PageIsNew(page))
+ {
+ HashPageOpaque pageopaque;
+
+ if (PageGetSpecialSize(page) != MAXALIGN(sizeof(HashPageOpaqueData)))
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("input page is not a valid %s page", "hash"),
+ errdetail("Expected special size %d, got %d.",
+ (int) MAXALIGN(sizeof(HashPageOpaqueData)),
+ (int) PageGetSpecialSize(page))));
+
+ pageopaque = (HashPageOpaque) PageGetSpecialPointer(page);
+ if (pageopaque->hasho_page_id != HASHO_PAGE_ID)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("input page is not a valid %s page", "hash"),
+ errdetail("Expected %08x, got %08x.",
+ HASHO_PAGE_ID, pageopaque->hasho_page_id)));
+
+ pagetype = pageopaque->hasho_flag & LH_PAGE_TYPE;
+ }
+
+ /* Check that page type is sane. */
+ if (pagetype != LH_OVERFLOW_PAGE && pagetype != LH_BUCKET_PAGE &&
+ pagetype != LH_BITMAP_PAGE && pagetype != LH_META_PAGE &&
+ pagetype != LH_UNUSED_PAGE)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("invalid hash page type %08x", pagetype)));
+
+ /* If requested, verify page type. */
+ if (flags != 0 && (pagetype & flags) == 0)
+ {
+ switch (flags)
+ {
+ case LH_META_PAGE:
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("page is not a hash meta page")));
+ break;
+ case LH_BUCKET_PAGE | LH_OVERFLOW_PAGE:
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("page is not a hash bucket or overflow page")));
+ break;
+ case LH_OVERFLOW_PAGE:
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("page is not a hash overflow page")));
+ break;
+ default:
+ elog(ERROR,
+ "hash page of type %08x not in mask %08x",
+ pagetype, flags);
+ break;
+ }
+ }
+
+ /*
+ * If it is the metapage, also verify magic number and version.
+ */
+ if (pagetype == LH_META_PAGE)
+ {
+ HashMetaPage metap = HashPageGetMeta(page);
+
+ if (metap->hashm_magic != HASH_MAGIC)
+ ereport(ERROR,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("invalid magic number for metadata"),
+ errdetail("Expected 0x%08x, got 0x%08x.",
+ HASH_MAGIC, metap->hashm_magic)));
+
+ if (metap->hashm_version != HASH_VERSION)
+ ereport(ERROR,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("invalid version for metadata"),
+ errdetail("Expected %d, got %d.",
+ HASH_VERSION, metap->hashm_version)));
+ }
+
+ return page;
+}
+
+/* -------------------------------------------------
+ * GetHashPageStatistics()
+ *
+ * Collect statistics of single hash page
+ * -------------------------------------------------
+ */
+static void
+GetHashPageStatistics(Page page, HashPageStat *stat)
+{
+ OffsetNumber maxoff = PageGetMaxOffsetNumber(page);
+ HashPageOpaque opaque = (HashPageOpaque) PageGetSpecialPointer(page);
+ int off;
+
+ stat->dead_items = stat->live_items = 0;
+ stat->page_size = PageGetPageSize(page);
+
+ /* hash page opaque data */
+ stat->hasho_prevblkno = opaque->hasho_prevblkno;
+ stat->hasho_nextblkno = opaque->hasho_nextblkno;
+ stat->hasho_bucket = opaque->hasho_bucket;
+ stat->hasho_flag = opaque->hasho_flag;
+ stat->hasho_page_id = opaque->hasho_page_id;
+
+ /* count live and dead tuples, and free space */
+ for (off = FirstOffsetNumber; off <= maxoff; off++)
+ {
+ ItemId id = PageGetItemId(page, off);
+
+ if (!ItemIdIsDead(id))
+ stat->live_items++;
+ else
+ stat->dead_items++;
+ }
+ stat->free_size = PageGetFreeSpace(page);
+}
+
+/* ---------------------------------------------------
+ * hash_page_type()
+ *
+ * Usage: SELECT hash_page_type(get_raw_page('con_hash_index', 1));
+ * ---------------------------------------------------
+ */
+Datum
+hash_page_type(PG_FUNCTION_ARGS)
+{
+ bytea *raw_page = PG_GETARG_BYTEA_P(0);
+ Page page;
+ HashPageOpaque opaque;
+ int pagetype;
+ const char *type;
+
+ if (!superuser())
+ ereport(ERROR,
+ (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+ errmsg("must be superuser to use raw page functions")));
+
+ page = verify_hash_page(raw_page, 0);
+
+ if (PageIsNew(page))
+ type = "unused";
+ else
+ {
+ opaque = (HashPageOpaque) PageGetSpecialPointer(page);
+
+ /* page type (flags) */
+ pagetype = opaque->hasho_flag & LH_PAGE_TYPE;
+ if (pagetype == LH_META_PAGE)
+ type = "metapage";
+ else if (pagetype == LH_OVERFLOW_PAGE)
+ type = "overflow";
+ else if (pagetype == LH_BUCKET_PAGE)
+ type = "bucket";
+ else if (pagetype == LH_BITMAP_PAGE)
+ type = "bitmap";
+ else
+ type = "unused";
+ }
+
+ PG_RETURN_TEXT_P(cstring_to_text(type));
+}
+
+/* ---------------------------------------------------
+ * hash_page_stats()
+ *
+ * Usage: SELECT * FROM hash_page_stats(get_raw_page('con_hash_index', 1));
+ * ---------------------------------------------------
+ */
+Datum
+hash_page_stats(PG_FUNCTION_ARGS)
+{
+ bytea *raw_page = PG_GETARG_BYTEA_P(0);
+ Page page;
+ int j;
+ Datum values[9];
+ bool nulls[9];
+ HashPageStat stat;
+ HeapTuple tuple;
+ TupleDesc tupleDesc;
+
+ if (!superuser())
+ ereport(ERROR,
+ (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+ errmsg("must be superuser to use raw page functions")));
+
+ page = verify_hash_page(raw_page, LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
+
+ /* keep compiler quiet */
+ stat.hasho_prevblkno = stat.hasho_nextblkno = InvalidBlockNumber;
+ stat.hasho_flag = stat.hasho_page_id = stat.free_size = 0;
+
+ GetHashPageStatistics(page, &stat);
+
+ /* 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);
+
+ MemSet(nulls, 0, sizeof(nulls));
+
+ j = 0;
+ values[j++] = Int32GetDatum(stat.live_items);
+ values[j++] = Int32GetDatum(stat.dead_items);
+ values[j++] = Int32GetDatum(stat.page_size);
+ values[j++] = Int32GetDatum(stat.free_size);
+ values[j++] = Int64GetDatum((int64) stat.hasho_prevblkno);
+ values[j++] = Int64GetDatum((int64) stat.hasho_nextblkno);
+ values[j++] = Int64GetDatum((int64) stat.hasho_bucket);
+ values[j++] = Int32GetDatum((int32) stat.hasho_flag);
+ values[j++] = Int32GetDatum((int32) stat.hasho_page_id);
+
+ tuple = heap_form_tuple(tupleDesc, values, nulls);
+
+ PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
+}
+
+/*
+ * cross-call data structure for SRF
+ */
+struct user_args
+{
+ Page page;
+ OffsetNumber offset;
+};
+
+/*-------------------------------------------------------
+ * hash_page_items()
+ *
+ * Get IndexTupleData set in a hash page
+ *
+ * Usage: SELECT * FROM hash_page_items(get_raw_page('con_hash_index', 1));
+ *-------------------------------------------------------
+ */
+Datum
+hash_page_items(PG_FUNCTION_ARGS)
+{
+ bytea *raw_page = PG_GETARG_BYTEA_P(0);
+ Page page;
+ Datum result;
+ Datum values[3];
+ bool nulls[3];
+ uint32 hashkey;
+ HeapTuple tuple;
+ FuncCallContext *fctx;
+ MemoryContext mctx;
+ 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())
+ {
+ TupleDesc tupleDesc;
+
+ fctx = SRF_FIRSTCALL_INIT();
+
+ mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
+
+ page = verify_hash_page(raw_page, LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
+
+ uargs = palloc(sizeof(struct user_args));
+
+ uargs->page = page;
+
+ uargs->offset = FirstOffsetNumber;
+
+ fctx->max_calls = PageGetMaxOffsetNumber(uargs->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");
+ tupleDesc = BlessTupleDesc(tupleDesc);
+
+ fctx->attinmeta = TupleDescGetAttInMetadata(tupleDesc);
+
+ fctx->user_fctx = uargs;
+
+ MemoryContextSwitchTo(mctx);
+ }
+
+ fctx = SRF_PERCALL_SETUP();
+ uargs = fctx->user_fctx;
+
+ if (fctx->call_cntr < fctx->max_calls)
+ {
+ ItemId id;
+ IndexTuple itup;
+ int j;
+
+ id = PageGetItemId(uargs->page, uargs->offset);
+
+ if (!ItemIdIsValid(id))
+ elog(ERROR, "invalid ItemId");
+
+ itup = (IndexTuple) PageGetItem(uargs->page, id);
+
+ MemSet(nulls, 0, sizeof(nulls));
+
+ j = 0;
+ values[j++] = Int32GetDatum((int32) uargs->offset);
+ values[j++] = PointerGetDatum(&itup->t_tid);
+
+ hashkey = _hash_get_indextuple_hashkey(itup);
+ values[j] = Int64GetDatum((int64) hashkey);
+
+ tuple = heap_form_tuple(fctx->attinmeta->tupdesc, values, nulls);
+ result = HeapTupleGetDatum(tuple);
+
+ uargs->offset = uargs->offset + 1;
+
+ SRF_RETURN_NEXT(fctx, result);
+ }
+
+ SRF_RETURN_DONE(fctx);
+}
+
+/* ------------------------------------------------
+ * hash_bitmap_info()
+ *
+ * Get bitmap information for a particular overflow page
+ *
+ * Usage: SELECT * FROM hash_bitmap_info('con_hash_index'::regclass, 5);
+ * ------------------------------------------------
+ */
+Datum
+hash_bitmap_info(PG_FUNCTION_ARGS)
+{
+ Oid indexRelid = PG_GETARG_OID(0);
+ int64 ovflblkno = PG_GETARG_INT64(1);
+ HashMetaPage metap;
+ Buffer metabuf,
+ mapbuf;
+ BlockNumber bitmapblkno;
+ Page mappage;
+ bool bit = false;
+ TupleDesc tupleDesc;
+ Relation indexRel;
+ uint32 ovflbitno;
+ int32 bitmappage,
+ bitmapbit;
+ HeapTuple tuple;
+ int i,
+ j;
+ Datum values[3];
+ bool nulls[3];
+ uint32 *freep;
+
+ if (!superuser())
+ ereport(ERROR,
+ (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+ errmsg("must be superuser to use raw page functions")));
+
+ indexRel = index_open(indexRelid, AccessShareLock);
+
+ if (!IS_HASH(indexRel))
+ ereport(ERROR,
+ (errcode(ERRCODE_WRONG_OBJECT_TYPE),
+ errmsg("\"%s\" is not a %s index",
+ RelationGetRelationName(indexRel), "hash")));
+
+ if (RELATION_IS_OTHER_TEMP(indexRel))
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot access temporary tables of other sessions")));
+
+ if (ovflblkno < 0 || ovflblkno > MaxBlockNumber)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("invalid block number")));
+
+ if (ovflblkno >= RelationGetNumberOfBlocks(indexRel))
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("block number %lld is out of range for relation \"%s\"",
+ (long long int) ovflblkno, RelationGetRelationName(indexRel))));
+
+ /* Read the metapage so we can determine which bitmap page to use */
+ metabuf = _hash_getbuf(indexRel, HASH_METAPAGE, HASH_READ, LH_META_PAGE);
+ metap = HashPageGetMeta(BufferGetPage(metabuf));
+
+ /*
+ * Reject attempt to read the bit for a metapage or bitmap page; this is
+ * only meaningful for overflow pages.
+ */
+ if (ovflblkno == 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("invalid overflow block number %u",
+ (BlockNumber) ovflblkno)));
+ for (i = 0; i < metap->hashm_nmaps; i++)
+ if (metap->hashm_mapp[i] == ovflblkno)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("invalid overflow block number %u",
+ (BlockNumber) ovflblkno)));
+
+ /*
+ * Identify overflow bit number. This will error out for primary bucket
+ * pages, and we've already rejected the metapage and bitmap pages above.
+ */
+ ovflbitno = _hash_ovflblkno_to_bitno(metap, (BlockNumber) ovflblkno);
+
+ bitmappage = ovflbitno >> BMPG_SHIFT(metap);
+ bitmapbit = ovflbitno & BMPG_MASK(metap);
+
+ if (bitmappage >= metap->hashm_nmaps)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("invalid overflow block number %u",
+ (BlockNumber) ovflblkno)));
+
+ bitmapblkno = metap->hashm_mapp[bitmappage];
+
+ _hash_relbuf(indexRel, metabuf);
+
+ /* Check the status of bitmap bit for overflow page */
+ mapbuf = _hash_getbuf(indexRel, bitmapblkno, HASH_READ, LH_BITMAP_PAGE);
+ mappage = BufferGetPage(mapbuf);
+ freep = HashPageGetBitmap(mappage);
+
+ bit = ISSET(freep, bitmapbit) != 0;
+
+ _hash_relbuf(indexRel, mapbuf);
+ index_close(indexRel, 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");
+ tupleDesc = BlessTupleDesc(tupleDesc);
+
+ MemSet(nulls, 0, sizeof(nulls));
+
+ j = 0;
+ values[j++] = Int64GetDatum((int64) bitmapblkno);
+ values[j++] = Int32GetDatum(bitmapbit);
+ values[j++] = BoolGetDatum(bit);
+
+ tuple = heap_form_tuple(tupleDesc, values, nulls);
+
+ PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
+}
+
+/* ------------------------------------------------
+ * hash_metapage_info()
+ *
+ * Get the meta-page information for a hash index
+ *
+ * Usage: SELECT * FROM hash_metapage_info(get_raw_page('con_hash_index', 0))
+ * ------------------------------------------------
+ */
+Datum
+hash_metapage_info(PG_FUNCTION_ARGS)
+{
+ bytea *raw_page = PG_GETARG_BYTEA_P(0);
+ Page page;
+ HashMetaPageData *metad;
+ TupleDesc tupleDesc;
+ HeapTuple tuple;
+ int i,
+ j;
+ Datum values[16];
+ bool nulls[16];
+ Datum spares[HASH_MAX_SPLITPOINTS];
+ Datum mapp[HASH_MAX_BITMAPS];
+
+ if (!superuser())
+ ereport(ERROR,
+ (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+ errmsg("must be superuser to use raw page functions")));
+
+ page = verify_hash_page(raw_page, LH_META_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");
+ tupleDesc = BlessTupleDesc(tupleDesc);
+
+ metad = HashPageGetMeta(page);
+
+ MemSet(nulls, 0, sizeof(nulls));
+
+ j = 0;
+ values[j++] = Int64GetDatum((int64) metad->hashm_magic);
+ values[j++] = Int64GetDatum((int64) metad->hashm_version);
+ values[j++] = Float8GetDatum(metad->hashm_ntuples);
+ values[j++] = Int32GetDatum((int32) metad->hashm_ffactor);
+ values[j++] = Int32GetDatum((int32) metad->hashm_bsize);
+ values[j++] = Int32GetDatum((int32) metad->hashm_bmsize);
+ values[j++] = Int32GetDatum((int32) metad->hashm_bmshift);
+ values[j++] = Int64GetDatum((int64) metad->hashm_maxbucket);
+ values[j++] = Int64GetDatum((int64) metad->hashm_highmask);
+ values[j++] = Int64GetDatum((int64) metad->hashm_lowmask);
+ values[j++] = Int64GetDatum((int64) metad->hashm_ovflpoint);
+ values[j++] = Int64GetDatum((int64) metad->hashm_firstfree);
+ values[j++] = Int64GetDatum((int64) metad->hashm_nmaps);
+ values[j++] = ObjectIdGetDatum((Oid) metad->hashm_procid);
+
+ for (i = 0; i < HASH_MAX_SPLITPOINTS; i++)
+ spares[i] = Int64GetDatum((int64) metad->hashm_spares[i]);
+ values[j++] = PointerGetDatum(construct_array(spares,
+ HASH_MAX_SPLITPOINTS,
+ INT8OID,
+ sizeof(int64),
+ FLOAT8PASSBYVAL,
+ TYPALIGN_DOUBLE));
+
+ for (i = 0; i < HASH_MAX_BITMAPS; i++)
+ mapp[i] = Int64GetDatum((int64) metad->hashm_mapp[i]);
+ values[j++] = PointerGetDatum(construct_array(mapp,
+ HASH_MAX_BITMAPS,
+ INT8OID,
+ sizeof(int64),
+ FLOAT8PASSBYVAL,
+ TYPALIGN_DOUBLE));
+
+ tuple = heap_form_tuple(tupleDesc, values, nulls);
+
+ PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-26 06:26:42 +0000