greenplumn hashfuncs 源码
greenplumn hashfuncs 代码
文件路径：/contrib/pageinspect/hashfuncs.c
/*
* hashfuncs.c
* Functions to investigate the content of HASH indexes
*
* Copyright (c) 2017-2019, PostgreSQL Global Development Group
*
* IDENTIFICATION
* contrib/pageinspect/hashfuncs.c
*/
#include "postgres.h"
#include "pageinspect.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"
#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_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)));
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);
}
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);
uint64 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))
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 (ovflblkno >= RelationGetNumberOfBlocks(indexRel))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("block number " UINT64_FORMAT " is out of range for relation \"%s\"",
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,
8, FLOAT8PASSBYVAL, 'd'));
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,
8, FLOAT8PASSBYVAL, 'd'));
tuple = heap_form_tuple(tupleDesc, values, nulls);
PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
}
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