postgresql/contrib/pageinspect/hashfuncs.c
Robert Haas 08bf6e5295 pageinspect: Support hash indexes.
Patch by Jesper Pedersen and Ashutosh Sharma, with some error handling
improvements by me.  Tests from Peter Eisentraut.  Reviewed by Álvaro
Herrera, Michael Paquier, Jesper Pedersen, Jeff Janes, Peter
Eisentraut, Amit Kapila, Mithun Cy, and me.

Discussion: http://postgr.es/m/e2ac6c58-b93f-9dd9-f4e6-d6d30add7fdf@redhat.com
2017-02-02 14:19:32 -05:00

560 lines
15 KiB
C

/*
* hashfuncs.c
* Functions to investigate the content of HASH indexes
*
* Copyright (c) 2017, PostgreSQL Global Development Group
*
* IDENTIFICATION
* contrib/pageinspect/hashfuncs.c
*/
#include "postgres.h"
#include "access/hash.h"
#include "access/htup_details.h"
#include "catalog/pg_type.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
{
uint16 live_items;
uint16 dead_items;
uint16 page_size;
uint16 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;
int pagetype;
HashPageOpaque pageopaque;
raw_page_size = VARSIZE(raw_page) - VARHDRSZ;
if (raw_page_size != BLCKSZ)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid page size"),
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 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)));
/* Check that page type is sane. */
pagetype = pageopaque->hasho_flag & LH_PAGE_TYPE;
if (pagetype != LH_OVERFLOW_PAGE && pagetype != LH_BUCKET_PAGE &&
pagetype != LH_BITMAP_PAGE && pagetype != LH_META_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")));
case LH_BUCKET_PAGE | LH_OVERFLOW_PAGE:
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("page is not a hash bucket or overflow page")));
case LH_OVERFLOW_PAGE:
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("page is not a hash overflow page")));
default:
elog(ERROR,
"hash page of type %08x not in mask %08x",
pagetype, flags);
}
}
/*
* 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;
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);
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('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++] = UInt16GetDatum(stat.live_items);
values[j++] = UInt16GetDatum(stat.dead_items);
values[j++] = UInt16GetDatum(stat.page_size);
values[j++] = UInt16GetDatum(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('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();
page = verify_hash_page(raw_page, LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
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++] = UInt16GetDatum(uargs->offset);
values[j++] = PointerGetDatum(&itup->t_tid);
hashkey = _hash_get_indextuple_hashkey(itup);
values[j] = UInt32GetDatum(hashkey);
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);
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);
uint32 ovflblkno = PG_GETARG_UINT32(1);
HashMetaPage metap;
Buffer buf,
metabuf;
BlockNumber bitmapblkno;
Page page;
bool bit = false;
HashPageOpaque opaque;
TupleDesc tupleDesc;
Relation indexRel;
uint32 ovflbitno;
int32 bitmappage,
bitmapbit;
HeapTuple tuple;
int j;
Datum values[3];
bool nulls[3];
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))
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))));
buf = ReadBufferExtended(indexRel, MAIN_FORKNUM, ovflblkno, RBM_NORMAL, NULL);
LockBuffer(buf, BUFFER_LOCK_SHARE);
_hash_checkpage(indexRel, buf, LH_PAGE_TYPE);
page = BufferGetPage(buf);
opaque = (HashPageOpaque) PageGetSpecialPointer(page);
if (opaque->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, opaque->hasho_flag)));
if (BlockNumberIsValid(opaque->hasho_prevblkno))
bit = true;
UnlockReleaseBuffer(buf);
/* 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 = _hash_ovflblkno_to_bitno(metap, 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 bit number %u", ovflbitno)));
bitmapblkno = metap->hashm_mapp[bitmappage];
_hash_relbuf(indexRel, metabuf);
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++] = 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++] = UInt32GetDatum(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);
for (i = 0; i < HASH_MAX_SPLITPOINTS; i++)
spares[i] = UInt32GetDatum(metad->hashm_spares[i]);
values[j++] = PointerGetDatum(construct_array(spares,
HASH_MAX_SPLITPOINTS,
INT8OID,
8, true, 'd'));
for (i = 0; i < HASH_MAX_BITMAPS; i++)
mapp[i] = UInt32GetDatum(metad->hashm_mapp[i]);
values[j++] = PointerGetDatum(construct_array(mapp,
HASH_MAX_BITMAPS,
INT8OID,
8, true, 'd'));
tuple = heap_form_tuple(tupleDesc, values, nulls);
PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
}