Hi All,
I have spent some time in reviewing the latest v8 patch from Jesper
and could find some issues which i would like to list down,
1) Firstly, the DATA section in the Makefile is referring to
"pageinspect--1.6.sql" file and currently this file is missing.
+DATA = pageinspect--1.6.sql pageinspect--1.5--1.6.sql
2) Secondly, I can see that the server is crashing when following
queries are executed on a code build with cassert-enabled.
postgres=# SELECT * FROM hash_page_items(get_raw_page('con_hash_index', 25000));
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!> \q
[ashu@localhost bin]$ ./psql -d postgres
psql (10devel)
Type "help" for help.
postgres=# SELECT * FROM hash_page_stats(get_raw_page('con_hash_index', 25000));
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!> \q
postgres=# SELECT * FROM
hash_metapage_info(get_raw_page('con_hash_index', 25000));
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!>
3) Thirdly, AFAIU the functions hash_page_stats() and
hash_page_items() are basically dedicated for bucket and overflow
pages in hash index and may not be used with bitmap page. It is
currently blocked for metapage but not for the bitmap page. I think we
need to block it for bitmap page as well.
Apart from issues listed above there are few other review comments
that has not been addressed yet. Considering the fact that it is a
very important project from hash index perspective and as there has
been no work being done on this project for quite some time, I thought
of working on it to close some of the open review comments along with
the issues found by myself. I would like to share the revised patch
which is based on Jesper's v8 patch. The patch has mainly following
following changes in it,
1) It introduces two new functions hash_page_type() and
hash_bitmap_info(). hash_page_type basically displays the type of hash
page whereas hash_bitmap_info() shows the status of a bit for a
particular overflow page in bitmap page of hash index.
2) The functions hash_page_stats() and hash_page_items() basically
shows the information about data stored in bucket and overflow pages
of hash index. If a metapage or bitmap page is passed as an input to
this function it throws an error saying "Expected page type:'' got:
''".
3) It also improves verify_hash_page() function to handle any type of
page in hash index. It is now being used as
verify_hash_page('raw_page', <page_type>) to verify if the page passed
to this function is of 'page_type' or not. Here page_type can be
LH_META_PAGE, LH_BUCKET_PAGE, LH_OVERFLOW_PAGE, LH_BITMAP_PAGE.
Attached is the revised patch. Please have a look and let me know your
feedback. I have also changed the status for this patch in the
upcoming commitfest to "needs review". Thanks.
From 46c375dbba6b345165b3a2130f5a582db18b813e Mon Sep 17 00:00:00 2001
From: ashu <ashu@localhost.localdomain>
Date: Tue, 20 Dec 2016 13:49:02 +0530
Subject: [PATCH] Add support for hash index in pageinspect contrib module v9
Revised patch by Ashutosh. Original patch was from Jesper
Pedersen.
---
contrib/pageinspect/Makefile | 10 +-
contrib/pageinspect/hashfuncs.c | 558 ++++++++++++++++++++++++++
contrib/pageinspect/pageinspect--1.5--1.6.sql | 76 ++++
contrib/pageinspect/pageinspect.control | 2 +-
doc/src/sgml/pageinspect.sgml | 149 +++++++
src/backend/access/hash/hashovfl.c | 12 +
src/include/access/hash.h | 1 +
7 files changed, 802 insertions(+), 6 deletions(-)
create mode 100644 contrib/pageinspect/hashfuncs.c
create mode 100644 contrib/pageinspect/pageinspect--1.5--1.6.sql
diff --git a/contrib/pageinspect/Makefile b/contrib/pageinspect/Makefile
index 87a28e9..6897f90 100644
--- a/contrib/pageinspect/Makefile
+++ b/contrib/pageinspect/Makefile
@@ -2,13 +2,13 @@
MODULE_big = pageinspect
OBJS = rawpage.o heapfuncs.o btreefuncs.o fsmfuncs.o \
- brinfuncs.o ginfuncs.o $(WIN32RES)
+ brinfuncs.o ginfuncs.o hashfuncs.o $(WIN32RES)
EXTENSION = pageinspect
-DATA = pageinspect--1.5.sql pageinspect--1.4--1.5.sql \
- pageinspect--1.3--1.4.sql pageinspect--1.2--1.3.sql \
- pageinspect--1.1--1.2.sql pageinspect--1.0--1.1.sql \
- pageinspect--unpackaged--1.0.sql
+DATA = pageinspect--1.5--1.6.sql pageinspect--1.5.sql \
+ pageinspect--1.4--1.5.sql pageinspect--1.3--1.4.sql \
+ pageinspect--1.2--1.3.sql pageinspect--1.1--1.2.sql \
+ pageinspect--1.0--1.1.sql pageinspect--unpackaged--1.0.sql
PGFILEDESC = "pageinspect - functions to inspect contents of database pages"
REGRESS = page btree brin gin
diff --git a/contrib/pageinspect/hashfuncs.c b/contrib/pageinspect/hashfuncs.c
new file mode 100644
index 0000000..5b9c848
--- /dev/null
+++ b/contrib/pageinspect/hashfuncs.c
@@ -0,0 +1,558 @@
+/*
+ * hashfuncs.c
+ * Functions to investigate the content of HASH indexes
+ *
+ * Copyright (c) 2016, 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 "funcapi.h"
+#include "miscadmin.h"
+#include "utils/builtins.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
+{
+ uint32 live_items;
+ uint32 dead_items;
+ uint32 page_size;
+ uint32 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 the page is returned.
+ */
+static Page
+verify_hash_page(bytea *raw_page, int flags)
+{
+ Page page;
+ int raw_page_size;
+ HashPageOpaque pageopaque;
+
+ raw_page_size = VARSIZE(raw_page) - VARHDRSZ;
+
+ if (raw_page_size != BLCKSZ)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("input page too small"),
+ errdetail("Expected size %d, got %d",
+ BLCKSZ, raw_page_size)));
+
+ page = VARDATA(raw_page);
+
+ if (PageIsNew(page))
+ ereport(ERROR,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index table contains unexpected zero page")));
+
+ if (PageGetSpecialSize(page) != MAXALIGN(sizeof(HashPageOpaqueData)))
+ ereport(ERROR,
+ (errcode(ERRCODE_INDEX_CORRUPTED),
+ errmsg("index table contains corrupted page")));
+
+ pageopaque = (HashPageOpaque) PageGetSpecialPointer(page);
+ if (pageopaque->hasho_page_id != HASHO_PAGE_ID)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("page is not a HASH page"),
+ errdetail("Expected %08x, got %08x.",
+ HASHO_PAGE_ID, pageopaque->hasho_page_id)));
+
+ if (!(pageopaque->hasho_flag & flags))
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("page is not a hash page of expected type"),
+ errdetail("Expected hash page type: %08x got: %08x.",
+ flags, pageopaque->hasho_flag)));
+ 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 */
+ if (opaque->hasho_flag & LH_BUCKET_PAGE)
+ stat->hasho_prevblkno = InvalidBlockNumber;
+ else
+ 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 * FROM hash_page_type(get_raw_page('t1_hash', 1));
+ * ---------------------------------------------------
+ */
+Datum
+hash_page_type(PG_FUNCTION_ARGS)
+{
+ bytea *raw_page = PG_GETARG_BYTEA_P(0);
+ Page page;
+ HashPageOpaque opaque;
+ 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, LH_META_PAGE | LH_BUCKET_PAGE |
+ LH_OVERFLOW_PAGE | LH_BITMAP_PAGE);
+ opaque = (HashPageOpaque) PageGetSpecialPointer(page);
+
+ /* page type (flags) */
+ if (opaque->hasho_flag & LH_META_PAGE)
+ type = "metapage";
+ else if (opaque->hasho_flag & LH_OVERFLOW_PAGE)
+ type = "overflow";
+ else if (opaque->hasho_flag & LH_BUCKET_PAGE)
+ type = "bucket";
+ else if (opaque->hasho_flag & 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('t1_hash', 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 pageinspect 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++] = UInt32GetDatum(stat.live_items);
+ values[j++] = UInt32GetDatum(stat.dead_items);
+ values[j++] = UInt32GetDatum(stat.page_size);
+ values[j++] = UInt32GetDatum(stat.free_size);
+ values[j++] = UInt32GetDatum(stat.hasho_prevblkno);
+ values[j++] = UInt32GetDatum(stat.hasho_nextblkno);
+ values[j++] = UInt32GetDatum(stat.hasho_bucket);
+ values[j++] = UInt16GetDatum(stat.hasho_flag);
+ values[j++] = UInt16GetDatum(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('t1_hash', 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];
+ HeapTuple tuple;
+ 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())
+ {
+ TupleDesc tupleDesc;
+
+ fctx = SRF_FIRSTCALL_INIT();
+
+ page = verify_hash_page(raw_page, LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
+
+ /*
+ * 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, page, BLCKSZ);
+
+ 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;
+ int off;
+ int dlen;
+ char *dump;
+ char *s;
+ char *ptr;
+
+ 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++] = UInt16GetDatum(uargs->offset);
+ values[j++] = CStringGetTextDatum(psprintf("(%u,%u)",
+ BlockIdGetBlockNumber(&(itup->t_tid.ip_blkid)),
+ itup->t_tid.ip_posid));
+
+ ptr = (char *) itup + IndexInfoFindDataOffset(itup->t_info);
+ dlen = IndexTupleSize(itup) - IndexInfoFindDataOffset(itup->t_info);
+ dump = palloc0(dlen * 3 + 1);
+ s = dump;
+ for (off = 0; off < dlen; off++)
+ {
+ if (off > 0)
+ *dump++ = ' ';
+ sprintf(dump, "%02x", *(ptr + off) & 0xff);
+ dump += 2;
+ }
+ values[j] = CStringGetTextDatum(s);
+
+ tuple = heap_form_tuple(fctx->attinmeta->tupdesc, values, nulls);
+ result = HeapTupleGetDatum(tuple);
+
+ uargs->offset = uargs->offset + 1;
+
+ SRF_RETURN_NEXT(fctx, result);
+ }
+ else
+ {
+ pfree(uargs->page);
+ pfree(uargs);
+ SRF_RETURN_DONE(fctx);
+ }
+}
+
+/* ------------------------------------------------
+ * hash_bitmap_info()
+ *
+ * Get bitmap information for a particular overflow page
+ *
+ * Usage: SELECT * FROM hash_bitmap_info('idx'::regclass, 5);
+ * ------------------------------------------------
+ */
+Datum
+hash_bitmap_info(PG_FUNCTION_ARGS)
+{
+ Oid indexRelid = PG_GETARG_OID(0);
+ uint32 ovflblkno = PG_GETARG_UINT32(1);
+ bytea *raw_page;
+ char *raw_page_data;
+ HashMetaPage metap;
+ Buffer buf, metabuf, mapbuf;
+ BlockNumber bitmapblkno;
+ Page page, mappage;
+ HashPageOpaque pageopaque;
+ TupleDesc tupleDesc;
+ Relation indexRel;
+ uint32 ovflbitno, bit = 0;
+ int32 bitmappage,bitmapbit;
+ HeapTuple tuple;
+ int j;
+ Datum values[2];
+ bool nulls[2];
+ uint32 *freep = NULL;
+
+ if (!superuser())
+ ereport(ERROR,
+ (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+ (errmsg("must be superuser to use pageinspect functions"))));
+
+ indexRel = index_open(indexRelid, AccessShareLock);
+
+ if (!IS_HASH(indexRel))
+ elog(ERROR, "relation \"%s\" is not a hash index",
+ RelationGetRelationName(indexRel));
+
+ if (RELATION_IS_OTHER_TEMP(indexRel))
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot access temporary tables of other sessions")));
+
+ if (RelationGetNumberOfBlocks(indexRel) <= (BlockNumber) (ovflblkno))
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("block number %u is out of range for relation \"%s\"",
+ ovflblkno, RelationGetRelationName(indexRel))));
+
+ /* Create a raw page */
+ raw_page = (bytea *) palloc(BLCKSZ + VARHDRSZ);
+ SET_VARSIZE(raw_page, BLCKSZ + VARHDRSZ);
+ raw_page_data = VARDATA(raw_page);
+
+ buf = ReadBufferExtended(indexRel, MAIN_FORKNUM, ovflblkno, RBM_NORMAL, NULL);
+ LockBuffer(buf, BUFFER_LOCK_SHARE);
+
+ memcpy(raw_page_data, BufferGetPage(buf), BLCKSZ);
+
+ LockBuffer(buf, BUFFER_LOCK_UNLOCK);
+ ReleaseBuffer(buf);
+
+ page = verify_hash_page(raw_page, LH_OVERFLOW_PAGE);
+ pageopaque = (HashPageOpaque) PageGetSpecialPointer(page);
+
+ if (pageopaque->hasho_flag != LH_OVERFLOW_PAGE)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("page is not an overflow page"),
+ errdetail("Expected %08x, got %08x.",
+ LH_OVERFLOW_PAGE, pageopaque->hasho_flag)));
+
+ /* 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));
+
+ /* Identify overflow bit number */
+ ovflbitno = convert_ovflblkno_to_bitno(metap, ovflblkno);
+
+ bitmappage = ovflbitno >> BMPG_SHIFT(metap);
+ bitmapbit = ovflbitno & BMPG_MASK(metap);
+
+ if (bitmappage >= metap->hashm_nmaps)
+ elog(ERROR, "invalid overflow bit number %u", ovflbitno);
+
+ bitmapblkno = metap->hashm_mapp[bitmappage];
+
+ /* Check the status of bitmap bit for overflow page */
+ mapbuf = _hash_getbuf(indexRel, bitmapblkno, HASH_WRITE, LH_BITMAP_PAGE);
+ mappage = BufferGetPage(mapbuf);
+ freep = HashPageGetBitmap(mappage);
+
+ if (ISSET(freep, bitmapbit))
+ bit = 1;
+
+ _hash_relbuf(indexRel, metabuf);
+
+ _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++] = UInt32GetDatum(bitmapblkno);
+ values[j++] = UInt32GetDatum(bit);
+
+ tuple = heap_form_tuple(tupleDesc, values, nulls);
+
+ PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
+}
+
+/* ------------------------------------------------
+ * hash_metapage_info()
+ *
+ * Get a hash's meta-page information
+ *
+ * Usage: SELECT * FROM hash_metapage_info(get_raw_page('t1_hash', 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];
+ char *spares;
+ char *mapp;
+ char *s;
+
+ if (!superuser())
+ ereport(ERROR,
+ (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+ (errmsg("must be superuser to use pageinspect 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++] = CStringGetTextDatum(psprintf("0x%08X", metad->hashm_magic));
+ values[j++] = UInt32GetDatum(metad->hashm_version);
+ values[j++] = Float8GetDatum(metad->hashm_ntuples);
+ values[j++] = UInt16GetDatum(metad->hashm_ffactor);
+ values[j++] = UInt16GetDatum(metad->hashm_bsize);
+ values[j++] = UInt16GetDatum(metad->hashm_bmsize);
+ values[j++] = UInt16GetDatum(metad->hashm_bmshift);
+ values[j++] = UInt32GetDatum(metad->hashm_maxbucket);
+ values[j++] = UInt32GetDatum(metad->hashm_highmask);
+ values[j++] = UInt32GetDatum(metad->hashm_lowmask);
+ values[j++] = UInt32GetDatum(metad->hashm_ovflpoint);
+ values[j++] = UInt32GetDatum(metad->hashm_firstfree);
+ values[j++] = UInt32GetDatum(metad->hashm_nmaps);
+ values[j++] = UInt16GetDatum(metad->hashm_procid);
+
+ spares = palloc0(HASH_MAX_SPLITPOINTS * 5 + 1);
+ s = spares;
+ for (i = 0; i < HASH_MAX_SPLITPOINTS; i++)
+ {
+ if (i > 0)
+ *spares++ = ' ';
+
+ sprintf(spares, "%04x", metad->hashm_spares[i]);
+ spares += 4;
+ }
+ values[j++] = CStringGetTextDatum(s);
+
+ mapp = palloc0(HASH_MAX_BITMAPS * 5 + 1);
+ s = mapp;
+ for (i = 0; i < HASH_MAX_BITMAPS; i++)
+ {
+ if (i > 0)
+ *mapp++ = ' ';
+
+ sprintf(mapp, "%04x", metad->hashm_mapp[i]);
+ mapp += 4;
+ }
+ values[j++] = CStringGetTextDatum(s);
+
+ tuple = heap_form_tuple(tupleDesc, values, nulls);
+
+ PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
+}
diff --git a/contrib/pageinspect/pageinspect--1.5--1.6.sql b/contrib/pageinspect/pageinspect--1.5--1.6.sql
new file mode 100644
index 0000000..08d844c
--- /dev/null
+++ b/contrib/pageinspect/pageinspect--1.5--1.6.sql
@@ -0,0 +1,76 @@
+/* contrib/pageinspect/pageinspect--1.5--1.6.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pageinspect UPDATE TO '1.6'" to load this file. \quit
+
+--
+-- HASH functions
+--
+
+--
+-- hash_page_type()
+--
+CREATE FUNCTION hash_page_type(IN page bytea)
+RETURNS text
+AS 'MODULE_PATHNAME', 'hash_page_type'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- hash_page_stats()
+--
+CREATE FUNCTION hash_page_stats(IN page bytea,
+ OUT live_items int4,
+ OUT dead_items int4,
+ OUT page_size int4,
+ OUT free_size int4,
+ OUT hasho_prevblkno int4,
+ OUT hasho_nextblkno int4,
+ OUT hasho_bucket int4,
+ OUT hasho_flag int4,
+ OUT hasho_page_id int4)
+AS 'MODULE_PATHNAME', 'hash_page_stats'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- hash_page_items()
+--
+CREATE FUNCTION hash_page_items(IN page bytea,
+ OUT itemoffset smallint,
+ OUT ctid tid,
+ OUT data text)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'hash_page_items'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- hash_bitmap_info()
+--
+CREATE FUNCTION hash_bitmap_info(IN index_oid regclass, IN blkno int4,
+ OUT bitmapblkno int4,
+ OUT bitmapbit int4)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'hash_bitmap_info'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+--
+-- hash_metapage_info()
+--
+CREATE FUNCTION hash_metapage_info(IN page bytea,
+ OUT magic text,
+ OUT version int4,
+ OUT ntuples double precision,
+ OUT ffactor int2,
+ OUT bsize int2,
+ OUT bmsize int2,
+ OUT bmshift int2,
+ OUT maxbucket int4,
+ OUT highmask int4,
+ OUT lowmask int4,
+ OUT ovflpoint int4,
+ OUT firstfree int4,
+ OUT nmaps int4,
+ OUT procid int4,
+ OUT spares text,
+ OUT mapp text)
+AS 'MODULE_PATHNAME', 'hash_metapage_info'
+LANGUAGE C STRICT PARALLEL SAFE;
diff --git a/contrib/pageinspect/pageinspect.control b/contrib/pageinspect/pageinspect.control
index 23c8eff..1a61c9f 100644
--- a/contrib/pageinspect/pageinspect.control
+++ b/contrib/pageinspect/pageinspect.control
@@ -1,5 +1,5 @@
# pageinspect extension
comment = 'inspect the contents of database pages at a low level'
-default_version = '1.5'
+default_version = '1.6'
module_pathname = '$libdir/pageinspect'
relocatable = true
diff --git a/doc/src/sgml/pageinspect.sgml b/doc/src/sgml/pageinspect.sgml
index d12dbac..839058f 100644
--- a/doc/src/sgml/pageinspect.sgml
+++ b/doc/src/sgml/pageinspect.sgml
@@ -493,4 +493,153 @@ test=# SELECT first_tid, nbytes, tids[0:5] AS some_tids
</variablelist>
</sect2>
+ <sect2>
+ <title>Hash Functions</title>
+
+ <variablelist>
+ <varlistentry>
+ <term>
+ <function>hash_page_type(page bytea) returns text</function>
+ <indexterm>
+ <primary>hash_page_type</primary>
+ </indexterm>
+ </term>
+
+ <listitem>
+ <para>
+ <function>hash_page_type</function> returns page type of
+ the given <acronym>HASH</acronym> index page. For example:
+<screen>
+test=# SELECT * FROM hash_page_type(get_raw_page('con_hash_index', 0));
+ hash_page_type
+----------------
+ metapage
+</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
+ <function>hash_page_stats(page bytea) returns setof record</function>
+ <indexterm>
+ <primary>hash_page_stats</primary>
+ </indexterm>
+ </term>
+
+ <listitem>
+ <para>
+ <function>hash_page_stats</function> returns information about
+ bucket or overflow page of <acronym>HASH</acronym> index. For
+ example:
+<screen>
+test=# SELECT * FROM hash_page_stats(get_raw_page('con_hash_index', 1));
+-[ RECORD 1 ]---+------
+live_items | 407
+dead_items | 0
+page_size | 8192
+free_size | 8
+hasho_prevblkno | -1
+hasho_nextblkno | 8474
+hasho_bucket | 0
+hasho_flag | 66
+hasho_page_id | 65408
+</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
+ <function>hash_page_items(page bytea) returns setof record</function>
+ <indexterm>
+ <primary>hash_page_items</primary>
+ </indexterm>
+ </term>
+
+ <listitem>
+ <para>
+ <function>hash_page_items</function> returns information about
+ the data stored in a bucket or overflow page of <acronym>HASH</acronym>
+ index page. For example:
+<screen>
+test=# SELECT * FROM hash_page_items(get_raw_page('con_hash_index', 1));
+ itemoffset | ctid | data
+------------+-----------------+-------------------------
+ 1 | (3145728,14376) | 00 c0 ca 3e 00 00 00 00
+ 2 | (3145728,14376) | 00 c0 ca 3e 00 00 00 00
+ 3 | (3407872,14376) | 00 c0 ca 3e 00 00 00 00
+ 4 | (3407872,14376) | 00 c0 ca 3e 00 00 00 00
+ 5 | (3407872,14376) | 00 c0 ca 3e 00 00 00 00
+...
+ 404 | (2883584,14120) | 00 c0 ca 3e 00 00 00 00
+ 405 | (2883584,13608) | 00 c0 ca 3e 00 00 00 00
+ 406 | (2621440,13096) | 00 c0 ca 3e 00 00 00 00
+ 407 | (2621440,12584) | 00 c0 ca 3e 00 00 00 00
+</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
+ <function>hash_bitmap_info(index oid, blkno int) returns record</function>
+ <indexterm>
+ <primary>hash_bitmap_info</primary>
+ </indexterm>
+ </term>
+
+ <listitem>
+ <para>
+ <function>hash_bitmap_info</function> returns information about the
+ the status of a bit for an overflow page in bitmap page of <acronym>HASH</acronym>
+ index. For example:
+<screen>
+test=# SELECT * FROM hash_bitmap_info('con_hash_index', 2050);
+ bitmapblkno | bitmapbit
+-------------+-----------
+ 65 | 1
+</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
+ <function>hash_metapage_info(page bytea) returns record</function>
+ <indexterm>
+ <primary>hash_metapage_info</primary>
+ </indexterm>
+ </term>
+
+ <listitem>
+ <para>
+ <function>hash_metapage_info</function> returns information stored
+ in meta page of a <acronym>HASH</acronym> index. For example:
+<screen>
+test=# SELECT * FROM hash_metapage_info(get_raw_page('con_hash_index', 0));
+-[ RECORD 1 ]-----------
+magic | 0x06440640
+version | 2
+ntuples | 686000
+ffactor | 40
+bsize | 8152
+bmsize | 4096
+bmshift | 15
+maxbucket | 17149
+highmask | 32767
+lowmask | 16383
+ovflpoint | 15
+firstfree | 2012
+nmaps | 1
+procid | 450
+spares | 0000 0000 0000 0000 0000 0000 0001 0001 0001 0001 0001 0004 003b 02c0 07c3 07dc 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
+mapp | 0041 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
+</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </sect2>
+
</sect1>
diff --git a/src/backend/access/hash/hashovfl.c b/src/backend/access/hash/hashovfl.c
index df7838c..458bc8f 100644
--- a/src/backend/access/hash/hashovfl.c
+++ b/src/backend/access/hash/hashovfl.c
@@ -802,3 +802,15 @@ _hash_squeezebucket(Relation rel,
/* NOTREACHED */
}
+
+/*
+ * convert_ovflblkno_to_bitno() - Returns the bitno corresponding
+ * to an overflow page. The function blkno_to_bitno() already
+ * does this but as it is a static function it cannot be called
+ * from outside this file.
+ */
+uint32
+convert_ovflblkno_to_bitno(HashMetaPage metap, BlockNumber ovflblkno)
+{
+ return blkno_to_bitno(metap, ovflblkno);
+}
diff --git a/src/include/access/hash.h b/src/include/access/hash.h
index 627fa2c..1794389 100644
--- a/src/include/access/hash.h
+++ b/src/include/access/hash.h
@@ -321,6 +321,7 @@ extern void _hash_squeezebucket(Relation rel,
Bucket bucket, BlockNumber bucket_blkno,
Buffer bucket_buf,
BufferAccessStrategy bstrategy);
+extern uint32 convert_ovflblkno_to_bitno(HashMetaPage metap, BlockNumber ovflblkno);
/* hashpage.c */
extern Buffer _hash_getbuf(Relation rel, BlockNumber blkno,
--
1.8.3.1
--
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