greenplumn bitmap 源码
greenplumn bitmap 代码
文件路径：/src/backend/access/bitmap/bitmap.c
/*-------------------------------------------------------------------------
*
* bitmap.c
* Implementation of the Hybrid Run-Length (HRL) on-disk bitmap index.
*
* Portions Copyright (c) 2007-2010 Greenplum Inc
* Portions Copyright (c) 2010-2012 EMC Corporation
* Portions Copyright (c) 2012-Present VMware, Inc. or its affiliates.
* Portions Copyright (c) 2006-2008, PostgreSQL Global Development Group
*
*
* IDENTIFICATION
* src/backend/access/bitmap/bitmap.c
*
* NOTES
* This file contains only the public interface routines.
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/amapi.h"
#include "access/amvalidate.h"
#include "access/genam.h"
#include "access/bitmap.h"
#include "access/bitmap_private.h"
#include "access/reloptions.h"
#include "access/nbtree.h" /* for btree_or_bitmap_validate() */
#include "access/tableam.h"
#include "access/xact.h"
#include "catalog/index.h"
#include "catalog/pg_am.h"
#include "catalog/pg_amproc.h"
#include "catalog/pg_opfamily.h"
#include "catalog/pg_opclass.h"
#include "miscadmin.h"
#include "nodes/tidbitmap.h"
#include "storage/lmgr.h"
#include "storage/smgr.h"
#include "parser/parse_oper.h"
#include "utils/memutils.h"
#include "utils/index_selfuncs.h"
#include "utils/syscache.h"
#include "nodes/execnodes.h"
static void bmbuildCallback(Relation index, ItemPointer tupleId, Datum *attdata,
bool *nulls, bool tupleIsAlive, void *state);
static bool words_get_match(BMBatchWords *words, BMIterateResult *result,
BlockNumber blockno, PagetableEntry *entry,
bool newentry);
static IndexScanDesc copy_scan_desc(IndexScanDesc scan);
static void indexstream_free(StreamNode *self);
static bool pull_stream(StreamBMIterator *iterator, PagetableEntry *e);
static void cleanup_pos(BMScanPosition pos);
/* type to hide BM specific stream state */
typedef struct BMStreamOpaque
{
IndexScanDesc scan;
PagetableEntry *entry;
/* Indicate that this stream contains no more bitmap words. */
bool is_done;
} BMStreamOpaque;
static void stream_free(BMStreamOpaque *so);
/*
* Bitmap index handler function: return IndexAmRoutine with access method parameters
* and callbacks.
*/
Datum
bmhandler(PG_FUNCTION_ARGS)
{
IndexAmRoutine *amroutine = makeNode(IndexAmRoutine);
/* these are mostly the same as B-tree */
amroutine->amstrategies = BTMaxStrategyNumber;
amroutine->amsupport = BTNProcs;
amroutine->amcanorder = false;
amroutine->amcanorderbyop = false;
amroutine->amcanbackward = false;
amroutine->amcanunique = true;
amroutine->amcanmulticol = true;
amroutine->amoptionalkey = true;
amroutine->amsearcharray = false;
amroutine->amsearchnulls = false;
amroutine->amstorage = false;
amroutine->amclusterable = false;
amroutine->ampredlocks = false;
amroutine->amkeytype = InvalidOid;
amroutine->ambuild = bmbuild;
amroutine->ambuildempty = bmbuildempty;
amroutine->aminsert = bminsert;
amroutine->ambulkdelete = bmbulkdelete;
amroutine->amvacuumcleanup = bmvacuumcleanup;
amroutine->amcanreturn = NULL;
amroutine->amcostestimate = bmcostestimate;
amroutine->amoptions = bmoptions;
amroutine->amproperty = NULL;
amroutine->amvalidate = bmvalidate;
amroutine->ambeginscan = bmbeginscan;
amroutine->amrescan = bmrescan;
amroutine->amgettuple = bmgettuple;
amroutine->amgetbitmap = bmgetbitmap;
amroutine->amendscan = bmendscan;
amroutine->ammarkpos = bmmarkpos;
amroutine->amrestrpos = bmrestrpos;
PG_RETURN_POINTER(amroutine);
}
/*
* bmbuild() -- Build a new bitmap index.
*/
IndexBuildResult *
bmbuild(Relation heap, Relation index, IndexInfo *indexInfo)
{
double reltuples;
BMBuildState bmstate;
IndexBuildResult *result;
TupleDesc tupDesc;
if (indexInfo->ii_Concurrent)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("CONCURRENTLY is not supported when creating bitmap indexes")));
/* We expect this to be called exactly once. */
if (RelationGetNumberOfBlocks(index) != 0)
ereport (ERROR,
(errcode(ERRCODE_INDEX_CORRUPTED),
errmsg("index \"%s\" already contains data",
RelationGetRelationName(index))));
tupDesc = RelationGetDescr(index);
/* initialize the bitmap index for MAIN_FORKNUM. */
_bitmap_init(index, RelationNeedsWAL(index), false);
/* initialize the build state. */
_bitmap_init_buildstate(index, &bmstate);
/* do the heap scan */
reltuples = table_index_build_scan(heap, index, indexInfo, true, true,
bmbuildCallback, (void *) &bmstate,
NULL);
/* clean up the build state */
_bitmap_cleanup_buildstate(index, &bmstate);
/* return statistics */
result = (IndexBuildResult *) palloc0(sizeof(IndexBuildResult));
result->heap_tuples = reltuples;
result->index_tuples = bmstate.ituples;
return result;
}
/*
* bmbuildempty() -- build an empty bitmap index in the initialization fork
*/
void
bmbuildempty(Relation indexrel)
{
/* initialize meta page and first LOV page for INIT_FORKNUM */
_bitmap_init(indexrel, true, true);
}
/*
* bminsert() -- insert an index tuple into a bitmap index.
*/
bool
bminsert(Relation rel, Datum *values, bool *isnull,
ItemPointer ht_ctid, Relation heapRel,
IndexUniqueCheck checkUnique,
IndexInfo *indexInfo)
{
_bitmap_doinsert(rel, *ht_ctid, values, isnull);
return true;
}
/*
* bmgettuple() -- return the next tuple in a scan.
*/
bool
bmgettuple(IndexScanDesc scan, ScanDirection dir)
{
BMScanOpaque so = (BMScanOpaque) scan->opaque;
bool res;
/* This implementation of a bitmap index is never lossy */
scan->xs_recheck = false;
/*
* If we have already begun our scan, continue in the same direction.
* Otherwise, start up the scan.
*/
if (so->bm_currPos && so->cur_pos_valid)
res = _bitmap_next(scan, dir);
else
res = _bitmap_first(scan, dir);
return res;
}
static void
stream_end_iterate(StreamBMIterator *self)
{
/* opaque may be NULL */
if (self->opaque) {
stream_free(self->opaque);
self->opaque = NULL;
}
}
static void
stream_begin_iterate(StreamNode *self, StreamBMIterator *iterator)
{
BMStreamOpaque *so;
IndexScanDesc scan = self->opaque;
iterator->pull = pull_stream;
iterator->end_iterate = stream_end_iterate;
if (scan == NULL)
{
iterator->opaque = NULL;
}
else
{
so = palloc(sizeof(BMStreamOpaque));
so->scan = copy_scan_desc(scan);
so->entry = NULL;
so->is_done = false;
iterator->opaque = so;
}
}
/*
* bmgetbitmap() -- return a stream bitmap.
*/
int64
bmgetbitmap(IndexScanDesc scan, Node **bmNodeP)
{
IndexStream *is;
BMScanPosition scanPos;
bool res;
res = _bitmap_firstbatchwords(scan, ForwardScanDirection);
scanPos = ((BMScanOpaque)scan->opaque)->bm_currPos;
/* perhaps this should be in a special context? */
is = (IndexStream *)palloc0(sizeof(IndexStream));
is->type = BMS_INDEX;
is->begin_iterate = stream_begin_iterate;
is->free = indexstream_free;
is->set_instrument = NULL;
is->upd_instrument = NULL;
is->opaque = NULL;
if (res)
{
int vec;
is->opaque = copy_scan_desc(scan);
/*
* Since we have made a copy for this scan, we reset the lov buffers
* in the original scan to make sure that these buffers will not
* be released.
*/
for (vec = 0; vec < scanPos->nvec; vec++)
{
BMVector bmvec = &(scanPos->posvecs[vec]);
bmvec->bm_lovBuffer = InvalidBuffer;
}
}
/*
* GPDB specific code. Since GPDB also support StreamBitmap
* in bitmap index. So normally we need to create specific bitmap
* node in the amgetbitmap AM.
*/
Assert(bmNodeP);
if (*bmNodeP == NULL)
{
StreamBitmap *sb = makeNode(StreamBitmap);
sb->streamNode = is;
*bmNodeP = (Node *) sb;
}
else if (IsA(*bmNodeP, StreamBitmap))
stream_add_node((StreamBitmap *)*bmNodeP, is, BMS_OR);
else
elog(ERROR, "non stream bitmap");
/*
* XXX We don't have a precise idea of the number of heap tuples
* involved.
*/
return 1;
}
/*
* bmbeginscan() -- start a scan on the bitmap index.
*/
IndexScanDesc
bmbeginscan(Relation rel, int nkeys, int norderbys)
{
IndexScanDesc scan;
BMScanOpaque so;
/* no order by operators allowed */
Assert(norderbys == 0);
/* get the scan */
scan = RelationGetIndexScan(rel, nkeys, norderbys);
/* allocate private workspace */
so = (BMScanOpaque) palloc(sizeof(BMScanOpaqueData));
so->bm_currPos = NULL;
so->bm_markPos = NULL;
so->cur_pos_valid = false;
so->mark_pos_valid = false;
scan->xs_itupdesc = RelationGetDescr(rel);
scan->opaque = so;
return scan;
}
/*
* bmrescan() -- restart a scan on the bitmap index.
*/
void
bmrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
ScanKey orderbys, int norderbys)
{
BMScanOpaque so = (BMScanOpaque) scan->opaque;
if (so->bm_currPos != NULL)
{
cleanup_pos(so->bm_currPos);
MemSet(so->bm_currPos, 0, sizeof(BMScanPositionData));
so->cur_pos_valid = false;
}
if (so->bm_markPos != NULL)
{
cleanup_pos(so->bm_markPos);
MemSet(so->bm_markPos, 0, sizeof(BMScanPositionData));
so->cur_pos_valid = false;
}
/* reset the scan key */
if (scankey && scan->numberOfKeys > 0)
memmove(scan->keyData, scankey,
scan->numberOfKeys * sizeof(ScanKeyData));
}
/*
* bmendscan() -- close a scan.
*/
void
bmendscan(IndexScanDesc scan)
{
BMScanOpaque so = (BMScanOpaque) scan->opaque;
/* free the space */
if (so->bm_currPos != NULL)
{
/*
* release the buffers that have been stored for each related
* bitmap vector.
*/
cleanup_pos(so->bm_currPos);
pfree(so->bm_currPos);
so->bm_currPos = NULL;
}
if (so->bm_markPos != NULL)
{
cleanup_pos(so->bm_markPos);
pfree(so->bm_markPos);
so->bm_markPos = NULL;
}
pfree(so);
scan->opaque = NULL;
}
/*
* bmmarkpos() -- save the current scan position.
*/
void
bmmarkpos(IndexScanDesc scan)
{
BMScanOpaque so = (BMScanOpaque) scan->opaque;
BMVector bmScanPos;
uint32 vectorNo;
/* free the space */
if (so->mark_pos_valid)
{
/*
* release the buffers that have been stored for each
* related bitmap.
*/
bmScanPos = so->bm_markPos->posvecs;
for (vectorNo=0; vectorNo < so->bm_markPos->nvec; vectorNo++)
{
if (BufferIsValid((bmScanPos[vectorNo]).bm_lovBuffer))
{
ReleaseBuffer((bmScanPos[vectorNo]).bm_lovBuffer);
(bmScanPos[vectorNo]).bm_lovBuffer = InvalidBuffer;
}
}
so->mark_pos_valid = false;
}
if (so->cur_pos_valid)
{
uint32 size = sizeof(BMScanPositionData);
/* set the mark position */
if (so->bm_markPos == NULL)
{
so->bm_markPos = (BMScanPosition) palloc(size);
}
bmScanPos = so->bm_currPos->posvecs;
for (vectorNo = 0; vectorNo < so->bm_currPos->nvec; vectorNo++)
{
if (BufferIsValid((bmScanPos[vectorNo]).bm_lovBuffer))
IncrBufferRefCount((bmScanPos[vectorNo]).bm_lovBuffer);
}
memcpy(so->bm_markPos->posvecs, bmScanPos,
so->bm_currPos->nvec *
sizeof(BMVectorData));
memcpy(so->bm_markPos, so->bm_currPos, size);
so->mark_pos_valid = true;
}
}
/*
* bmrestrpos() -- restore a scan to the last saved position.
*/
void
bmrestrpos(IndexScanDesc scan)
{
BMScanOpaque so = (BMScanOpaque) scan->opaque;
BMVector bmScanPos;
uint32 vectorNo;
/* free space */
if (so->cur_pos_valid)
{
/* release the buffers that have been stored for each related bitmap.*/
bmScanPos = so->bm_currPos->posvecs;
for (vectorNo=0; vectorNo<so->bm_markPos->nvec;
vectorNo++)
{
if (BufferIsValid((bmScanPos[vectorNo]).bm_lovBuffer))
{
ReleaseBuffer((bmScanPos[vectorNo]).bm_lovBuffer);
(bmScanPos[vectorNo]).bm_lovBuffer = InvalidBuffer;
}
}
so->cur_pos_valid = false;
}
if (so->mark_pos_valid)
{
uint32 size = sizeof(BMScanPositionData);
/* set the current position */
if (so->bm_currPos == NULL)
{
so->bm_currPos = (BMScanPosition) palloc0(size);
}
bmScanPos = so->bm_markPos->posvecs;
for (vectorNo=0; vectorNo<so->bm_currPos->nvec;
vectorNo++)
{
if (BufferIsValid((bmScanPos[vectorNo]).bm_lovBuffer))
IncrBufferRefCount((bmScanPos[vectorNo]).bm_lovBuffer);
}
memcpy(so->bm_currPos->posvecs, bmScanPos,
so->bm_markPos->nvec *
sizeof(BMVectorData));
memcpy(so->bm_currPos, so->bm_markPos, size);
so->cur_pos_valid = true;
}
}
/*
* bmbulkdelete() -- bulk delete index entries
*
* Re-index is performed before retrieving the number of tuples
* indexed in this index.
*/
IndexBulkDeleteResult *
bmbulkdelete(IndexVacuumInfo *info,
IndexBulkDeleteResult *stats,
IndexBulkDeleteCallback callback,
void *callback_state)
{
Relation rel = info->index;
/* allocate stats if first time through, else re-use existing struct */
if (stats == NULL)
stats = (IndexBulkDeleteResult *)
palloc0(sizeof(IndexBulkDeleteResult));
reindex_index(RelationGetRelid(rel), true, rel->rd_rel->relpersistence, 0);
CommandCounterIncrement();
stats->num_pages = RelationGetNumberOfBlocks(rel);
/* Since we re-build the index, set this to number of heap tuples. */
stats->num_index_tuples = info->num_heap_tuples;
stats->tuples_removed = 0;
return stats;
}
/*
* bmvacuumcleanup() -- post-vacuum cleanup.
*
* We do nothing useful here.
*/
IndexBulkDeleteResult *
bmvacuumcleanup(IndexVacuumInfo *info,
IndexBulkDeleteResult *stats)
{
Relation rel = info->index;
if(stats == NULL)
stats = (IndexBulkDeleteResult *)palloc0(sizeof(IndexBulkDeleteResult));
/* update statistics */
stats->num_pages = RelationGetNumberOfBlocks(rel);
stats->pages_deleted = 0;
stats->pages_free = 0;
/* XXX: dodgy hack to shutup index_scan() and vacuum_index() */
stats->num_index_tuples = info->num_heap_tuples;
return stats;
}
/*
* Per-tuple callback from IndexBuildHeapScan
*/
static void
bmbuildCallback(Relation index, ItemPointer tupleId, Datum *attdata,
bool *nulls, bool tupleIsAlive pg_attribute_unused(), void *state)
{
BMBuildState *bstate = (BMBuildState *) state;
_bitmap_buildinsert(index, *tupleId, attdata, nulls, bstate);
bstate->ituples += 1;
if (((int)bstate->ituples) % 1000 == 0)
CHECK_FOR_INTERRUPTS();
}
/*
* Free an IndexScanDesc created by copy_scan_desc(). If releaseBuffers is true,
* any Buffers pointed to by the BMScanPositions will be released as well.
*/
static void
free_scan_desc(IndexScanDesc scan, bool releaseBuffers)
{
BMScanOpaque s = scan->opaque;
int vec;
if (s->bm_currPos)
{
if (!releaseBuffers)
{
for (vec = 0; vec < s->bm_currPos->nvec; vec++)
{
BMVector bmvec = &(s->bm_currPos->posvecs[vec]);
bmvec->bm_lovBuffer = InvalidBuffer;
}
}
cleanup_pos(s->bm_currPos);
pfree(s->bm_currPos);
s->bm_currPos = NULL;
}
if (s->bm_markPos)
{
if (!releaseBuffers)
{
for (vec = 0; vec < s->bm_markPos->nvec; vec++)
{
BMVector bmvec = &(s->bm_markPos->posvecs[vec]);
bmvec->bm_lovBuffer = InvalidBuffer;
}
}
cleanup_pos(s->bm_markPos);
pfree(s->bm_markPos);
s->bm_markPos = NULL;
}
pfree(s);
pfree(scan);
}
/*
* free the memory associated with the stream
*/
static void
stream_free(BMStreamOpaque *so)
{
/* opaque may be NULL */
if (so)
{
free_scan_desc(so->scan, false /* we can't release the underlying
Buffers yet as there may be other
iterators in operation */);
if (so->entry != NULL)
pfree(so->entry);
pfree(so);
}
}
/*
* free the memory associated with an IndexStream
*/
static void
indexstream_free(StreamNode *self) {
IndexScanDesc scan = self->opaque;
if (scan)
free_scan_desc(scan, true /* we can release the scanned Buffers now */);
pfree(self);
}
static void
cleanup_pos(BMScanPosition pos)
{
if (pos->nvec == 0)
return;
/*
* Only cleanup bm_batchWords if we have more than one vector since
* _bitmap_cleanup_scanpos() will clean it up for the single vector
* case.
*/
if (pos->nvec > 1)
{
_bitmap_cleanup_batchwords(pos->bm_batchWords);
if (pos->bm_batchWords != NULL)
pfree(pos->bm_batchWords);
}
_bitmap_cleanup_scanpos(pos->posvecs, pos->nvec);
}
/*
* pull the next block of tids from a bitmap stream
*/
static bool
pull_stream(StreamBMIterator *iterator, PagetableEntry *e)
{
bool res = false;
bool newentry = true;
PagetableEntry *next;
BMScanPosition scanPos;
IndexScanDesc scan;
BMStreamOpaque *so = iterator->opaque;
/* empty bitmap vector */
if(so == NULL)
return false;
next = so->entry;
/* have we already got an entry? */
if(next && iterator->nextblock <= next->blockno)
{
memcpy(e, next, sizeof(PagetableEntry));
return true;
}
else if (so->is_done)
{
/* Just free opaque state early so that we could short circuit. */
if (iterator->opaque) {
stream_free(iterator->opaque);
iterator->opaque = NULL;
}
return false;
}
scan = so->scan;
scanPos = ((BMScanOpaque)scan->opaque)->bm_currPos;
e->blockno = iterator->nextblock;
so->is_done = false;
while(true)
{
bool found;
CHECK_FOR_INTERRUPTS();
if (scanPos != NULL)
res = _bitmap_nextbatchwords(scan, ForwardScanDirection);
else
/* we should be initialised! */
elog(ERROR, "scan position uninitialized");
found = words_get_match(scanPos->bm_batchWords, &(scanPos->bm_result),
iterator->nextblock, e, newentry);
if(found)
{
res = true;
break;
}
else
{
/* Are there any more words available from the index itself? */
if(!res)
{
so->is_done = true;
res = true;
break;
}
else
{
/*
* We didn't have enough words to match the whole page, so
* tell words_get_match() to continue looking at the page
* it finished at
*/
iterator->nextblock = e->blockno;
newentry = false;
}
}
}
/*
* Set the next block number. We want to skip those blocks that do not
* contain possible query results, since in AO index cases, this range
* can be very large.
*/
iterator->nextblock = e->blockno + 1;
if (scanPos->bm_result.nextTid / BM_MAX_TUPLES_PER_PAGE > e->blockno + 1)
iterator->nextblock = scanPos->bm_result.nextTid / BM_MAX_TUPLES_PER_PAGE;
if (so->entry == NULL)
so->entry = (PagetableEntry *) palloc(sizeof(PagetableEntry));
memcpy(so->entry, e, sizeof(PagetableEntry));
return res;
}
/*
* Make a copy of an index scan descriptor as well as useful fields in
* the opaque structure
*/
static IndexScanDesc
copy_scan_desc(IndexScanDesc scan)
{
IndexScanDesc s;
BMScanOpaque so;
BMScanPosition sp;
BMScanPosition spcopy;
BMBatchWords *w;
BMVector bsp;
/* we only need a few fields */
s = (IndexScanDesc)palloc0(sizeof(IndexScanDescData));
s->opaque = palloc(sizeof(BMScanOpaqueData));
s->indexRelation = scan->indexRelation;
so = (BMScanOpaque)scan->opaque;
sp = so->bm_currPos;
if(sp)
{
int vec;
spcopy = palloc0(sizeof(BMScanPositionData));
spcopy->done = sp->done;
spcopy->nvec = sp->nvec;
/* now the batch words */
w = (BMBatchWords *)palloc(sizeof(BMBatchWords));
w->hwords = palloc0(sizeof(BM_HRL_WORD) *
BM_CALC_H_WORDS(sp->bm_batchWords->maxNumOfWords));
w->cwords = palloc0(sizeof(BM_HRL_WORD) *
sp->bm_batchWords->maxNumOfWords);
_bitmap_copy_batchwords(sp->bm_batchWords, w);
spcopy->bm_batchWords = w;
memcpy(&spcopy->bm_result, &sp->bm_result, sizeof(BMIterateResult));
bsp = (BMVector)palloc(sizeof(BMVectorData) * sp->nvec);
spcopy->posvecs = bsp;
if(sp->nvec == 1)
{
bsp->bm_lovBuffer = sp->posvecs->bm_lovBuffer;
bsp->bm_lovOffset = sp->posvecs->bm_lovOffset;
bsp->bm_nextBlockNo = sp->posvecs->bm_nextBlockNo;
bsp->bm_readLastWords = sp->posvecs->bm_readLastWords;
bsp->bm_batchWords = w;
}
else
{
for (vec = 0; vec < sp->nvec; vec++)
{
BMVector bmScanPos = &(bsp[vec]);
BMVector spp = &(sp->posvecs[vec]);
bmScanPos->bm_lovBuffer = spp->bm_lovBuffer;
bmScanPos->bm_lovOffset = spp->bm_lovOffset;
bmScanPos->bm_nextBlockNo = spp->bm_nextBlockNo;
bmScanPos->bm_readLastWords = spp->bm_readLastWords;
bmScanPos->bm_batchWords =
(BMBatchWords *) palloc0(sizeof(BMBatchWords));
_bitmap_init_batchwords(bmScanPos->bm_batchWords,
BM_NUM_OF_HRL_WORDS_PER_PAGE,
CurrentMemoryContext);
_bitmap_copy_batchwords(spp->bm_batchWords,
bmScanPos->bm_batchWords);
}
}
}
else
spcopy = NULL;
((BMScanOpaque)s->opaque)->bm_currPos = spcopy;
((BMScanOpaque)s->opaque)->bm_markPos = NULL;
return s;
}
/*
* Given a set of bitmap words and our current position, get the next
* page with matches on it.
*
* If newentry is false, we're calling the function with a partially filled
* page table entry. Otherwise, the entry is empty.
*
* This function is only used in stream bitmap scan, more specifically, it's
* BitmapIndexScan + BitmapHeapScan.
*/
static bool
words_get_match(BMBatchWords *words, BMIterateResult *result,
BlockNumber blockno, PagetableEntry *entry, bool newentry)
{
tbm_bitmapword newWord;
int nhrlwords = (TBM_BITS_PER_BITMAPWORD/BM_HRL_WORD_SIZE);
int hrlwordno;
int newwordno;
uint64 start, end;
/*
* XXX: We assume that BM_HRL_WORD_SIZE is not greater than
* TBM_BITS_PER_BITMAPWORD for tidbitmap.
*/
Assert(BM_HRL_WORD_SIZE <= TBM_BITS_PER_BITMAPWORD);
Assert(nhrlwords >= 1);
restart:
/* compute the first and last tid location for 'blockno' */
start = ((uint64)blockno) * BM_MAX_TUPLES_PER_PAGE + 1;
end = ((uint64)(blockno + 1)) * BM_MAX_TUPLES_PER_PAGE;
newwordno = 0;
hrlwordno = 0;
/* If we have read past the requested block, simple return true. */
if (result->nextTid > end)
return true;
if (result->lastScanWordNo >= words->maxNumOfWords)
{
result->lastScanWordNo = 0;
if (result->nextTid < end)
return false;
else
return true;
}
Assert((result->nextTid - start) % BM_HRL_WORD_SIZE == 0);
/* Set the next tid we expected to check */
result->nextTid = start;
/*
* If words->firstTid < result->nextTid, we need to catch up the words
* firstTid for checking to the next tid(start of current block).
* words->firstTid will keep set as result->nextTid before each
* iteration to mark the scanned tids in _bitmap_nextbatchwords.
* Note here that when we read new batchwords from bitmap page, the
* words->firstTid may get set to a tid we already scanned.
* See read_words in bitmapsearch.c.
*
* If the words->firstTid already pass the result->nextTid, then
* we should scan from the words->firstTid. Since the new batchwords's
* start tid exceeds block's start tid.
*/
if (words->firstTid < result->nextTid)
_bitmap_catchup_to_next_tid(words, result);
else if (words->firstTid > result->nextTid)
result->nextTid = words->firstTid;
/*
* Current words may not contain the expected nextTid, since the
* blockno may skiped several blocks if BitmapAdd choose to skip
* the blockno that can not be matched.
*/
if (words->firstTid < result->nextTid)
{
Assert(words->nwords == 0);
return false;
}
/*
* If the catch up processd all unmatch words that exceed current block's
* end. Then restart for a new block.
*/
if (result->nextTid > end)
{
blockno = result->nextTid / BM_MAX_TUPLES_PER_PAGE;
goto restart;
}
/*
* if there are no such a bitmap in the given batch words, then
* return false.
*/
if (words->nwords == 0)
{
result->lastScanWordNo = 0;
return false;
}
/*
* If the the nextTid is the firstTid, then we exam the leading
* 0 fill words. And skip them.
*/
if (IS_FILL_WORD(words->hwords, result->lastScanWordNo) &&
GET_FILL_BIT(words->cwords[result->lastScanWordNo]) == 0)
{
uint64 filllen;
BM_HRL_WORD word = words->cwords[result->lastScanWordNo];
if(word == 0)
filllen = 1;
else
filllen = FILL_LENGTH(word);
/*
* Check if the fill word would take us past the end of the block
* we're currently interested in.
*/
if(filllen * BM_HRL_WORD_SIZE > end - result->nextTid)
{
result->nextTid += filllen * BM_HRL_WORD_SIZE;
blockno = result->nextTid / BM_MAX_TUPLES_PER_PAGE;
result->lastScanWordNo++;
words->nwords--;
if(newentry)
{
/* Mark the scanned tids */
words->firstTid = result->nextTid;
goto restart;
}
else
return true;
}
}
/* copy the bitmap for tuples in the given heap page. */
newWord = 0;
hrlwordno = ((result->nextTid - start) / BM_HRL_WORD_SIZE) % nhrlwords;
newwordno = (result->nextTid - start) / TBM_BITS_PER_BITMAPWORD;
while (words->nwords > 0 && result->nextTid < end)
{
BM_HRL_WORD word = words->cwords[result->lastScanWordNo];
if (IS_FILL_WORD(words->hwords, result->lastScanWordNo))
{
if (GET_FILL_BIT(word) == 1)
{
newWord |= ((tbm_bitmapword)(LITERAL_ALL_ONE)) <<
(hrlwordno * BM_HRL_WORD_SIZE);
}
words->cwords[result->lastScanWordNo]--;
if (FILL_LENGTH(words->cwords[result->lastScanWordNo]) == 0)
{
result->lastScanWordNo++;
words->nwords--;
}
}
else
{
newWord |= ((tbm_bitmapword)word) << (hrlwordno * BM_HRL_WORD_SIZE);
result->lastScanWordNo++;
words->nwords--;
}
hrlwordno = (hrlwordno + 1) % nhrlwords;
result->nextTid += BM_HRL_WORD_SIZE;
if (hrlwordno % nhrlwords == 0)
{
Assert(newwordno < WORDS_PER_PAGE || newwordno < WORDS_PER_CHUNK);
entry->words[newwordno] |= newWord;
newwordno++;
/* reset newWord */
newWord = 0;
}
}
if (hrlwordno % nhrlwords != 0)
{
Assert(newwordno < WORDS_PER_PAGE || newwordno < WORDS_PER_CHUNK);
entry->words[newwordno] |= newWord;
}
entry->blockno = blockno;
if (words->nwords == 0)
{
result->lastScanWordNo = 0;
if (result->nextTid < end)
return false;
}
return true;
}
/*
* GetBitmapIndexAuxOids - Given an open index, fetch and return the oids for
* the bitmap subobjects (pg_bm_xxxx + pg_bm_xxxx_index).
*
* Note: Currently this information is not stored directly in the catalog, but
* is hidden away inside the metadata page of the index. Future versions should
* move this information into the catalog.
*/
void
GetBitmapIndexAuxOids(Relation index, Oid *heapId, Oid *indexId)
{
Buffer metabuf;
BMMetaPage metapage;
/* Only Bitmap Indexes have bitmap related sub-objects */
if (!RelationIsBitmapIndex(index))
{
*heapId = InvalidOid;
*indexId = InvalidOid;
return;
}
metabuf = _bitmap_getbuf(index, BM_METAPAGE, BM_READ);
metapage = _bitmap_get_metapage_data(index, metabuf);
*heapId = metapage->bm_lov_heapId;
*indexId = metapage->bm_lov_indexId;
_bitmap_relbuf(metabuf);
}
bytea *
bmoptions(Datum reloptions, bool validate)
{
return default_reloptions(reloptions, validate, RELOPT_KIND_BITMAP);
}
/*
* Ask appropriate access method to validate the specified opclass.
*/
bool
bmvalidate(Oid opclassoid)
{
/*
* Bitmap indexes use the same opclass support functions and strategies
* as B-tree indexes. In fact, we use a real B-tree index for the LOV
* tree. So borrow B-tree's validate function.
*/
return btree_or_bitmap_validate(opclassoid, "bitmap");
}
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