greenplumn blutils 源码
greenplumn blutils 代码
文件路径：/contrib/bloom/blutils.c
/*-------------------------------------------------------------------------
*
* blutils.c
* Bloom index utilities.
*
* Portions Copyright (c) 2016-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1990-1993, Regents of the University of California
*
* IDENTIFICATION
* contrib/bloom/blutils.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/amapi.h"
#include "access/generic_xlog.h"
#include "catalog/index.h"
#include "storage/lmgr.h"
#include "miscadmin.h"
#include "storage/bufmgr.h"
#include "storage/indexfsm.h"
#include "utils/memutils.h"
#include "access/reloptions.h"
#include "storage/freespace.h"
#include "storage/indexfsm.h"
#include "bloom.h"
/* Signature dealing macros - note i is assumed to be of type int */
#define GETWORD(x,i) ( *( (BloomSignatureWord *)(x) + ( (i) / SIGNWORDBITS ) ) )
#define CLRBIT(x,i) GETWORD(x,i) &= ~( 0x01 << ( (i) % SIGNWORDBITS ) )
#define SETBIT(x,i) GETWORD(x,i) |= ( 0x01 << ( (i) % SIGNWORDBITS ) )
#define GETBIT(x,i) ( (GETWORD(x,i) >> ( (i) % SIGNWORDBITS )) & 0x01 )
PG_FUNCTION_INFO_V1(blhandler);
/* Kind of relation options for bloom index */
static relopt_kind bl_relopt_kind;
/* parse table for fillRelOptions */
static relopt_parse_elt bl_relopt_tab[INDEX_MAX_KEYS + 1];
static int32 myRand(void);
static void mySrand(uint32 seed);
/*
* Module initialize function: initialize info about Bloom relation options.
*
* Note: keep this in sync with makeDefaultBloomOptions().
*/
void
_PG_init(void)
{
int i;
char buf[16];
bl_relopt_kind = add_reloption_kind();
/* Option for length of signature */
add_int_reloption(bl_relopt_kind, "length",
"Length of signature in bits",
DEFAULT_BLOOM_LENGTH, 1, MAX_BLOOM_LENGTH);
bl_relopt_tab[0].optname = "length";
bl_relopt_tab[0].opttype = RELOPT_TYPE_INT;
bl_relopt_tab[0].offset = offsetof(BloomOptions, bloomLength);
/* Number of bits for each possible index column: col1, col2, ... */
for (i = 0; i < INDEX_MAX_KEYS; i++)
{
snprintf(buf, sizeof(buf), "col%d", i + 1);
add_int_reloption(bl_relopt_kind, buf,
"Number of bits generated for each index column",
DEFAULT_BLOOM_BITS, 1, MAX_BLOOM_BITS);
bl_relopt_tab[i + 1].optname = MemoryContextStrdup(TopMemoryContext,
buf);
bl_relopt_tab[i + 1].opttype = RELOPT_TYPE_INT;
bl_relopt_tab[i + 1].offset = offsetof(BloomOptions, bitSize[0]) + sizeof(int) * i;
}
}
/*
* Construct a default set of Bloom options.
*/
static BloomOptions *
makeDefaultBloomOptions(void)
{
BloomOptions *opts;
int i;
opts = (BloomOptions *) palloc0(sizeof(BloomOptions));
/* Convert DEFAULT_BLOOM_LENGTH from # of bits to # of words */
opts->bloomLength = (DEFAULT_BLOOM_LENGTH + SIGNWORDBITS - 1) / SIGNWORDBITS;
for (i = 0; i < INDEX_MAX_KEYS; i++)
opts->bitSize[i] = DEFAULT_BLOOM_BITS;
SET_VARSIZE(opts, sizeof(BloomOptions));
return opts;
}
/*
* Bloom handler function: return IndexAmRoutine with access method parameters
* and callbacks.
*/
Datum
blhandler(PG_FUNCTION_ARGS)
{
IndexAmRoutine *amroutine = makeNode(IndexAmRoutine);
amroutine->amstrategies = BLOOM_NSTRATEGIES;
amroutine->amsupport = BLOOM_NPROC;
amroutine->amcanorder = false;
amroutine->amcanorderbyop = false;
amroutine->amcanbackward = false;
amroutine->amcanunique = false;
amroutine->amcanmulticol = true;
amroutine->amoptionalkey = true;
amroutine->amsearcharray = false;
amroutine->amsearchnulls = false;
amroutine->amstorage = false;
amroutine->amclusterable = false;
amroutine->ampredlocks = false;
amroutine->amcanparallel = false;
amroutine->amcaninclude = false;
amroutine->amkeytype = InvalidOid;
amroutine->ambuild = blbuild;
amroutine->ambuildempty = blbuildempty;
amroutine->aminsert = blinsert;
amroutine->ambulkdelete = blbulkdelete;
amroutine->amvacuumcleanup = blvacuumcleanup;
amroutine->amcanreturn = NULL;
amroutine->amcostestimate = blcostestimate;
amroutine->amoptions = bloptions;
amroutine->amproperty = NULL;
amroutine->ambuildphasename = NULL;
amroutine->amvalidate = blvalidate;
amroutine->ambeginscan = blbeginscan;
amroutine->amrescan = blrescan;
amroutine->amgettuple = NULL;
amroutine->amgetbitmap = blgetbitmap;
amroutine->amendscan = blendscan;
amroutine->ammarkpos = NULL;
amroutine->amrestrpos = NULL;
amroutine->amestimateparallelscan = NULL;
amroutine->aminitparallelscan = NULL;
amroutine->amparallelrescan = NULL;
PG_RETURN_POINTER(amroutine);
}
/*
* Fill BloomState structure for particular index.
*/
void
initBloomState(BloomState *state, Relation index)
{
int i;
state->nColumns = index->rd_att->natts;
/* Initialize hash function for each attribute */
for (i = 0; i < index->rd_att->natts; i++)
{
fmgr_info_copy(&(state->hashFn[i]),
index_getprocinfo(index, i + 1, BLOOM_HASH_PROC),
CurrentMemoryContext);
state->collations[i] = index->rd_indcollation[i];
}
/* Initialize amcache if needed with options from metapage */
if (!index->rd_amcache)
{
Buffer buffer;
Page page;
BloomMetaPageData *meta;
BloomOptions *opts;
opts = MemoryContextAlloc(index->rd_indexcxt, sizeof(BloomOptions));
buffer = ReadBuffer(index, BLOOM_METAPAGE_BLKNO);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
page = BufferGetPage(buffer);
if (!BloomPageIsMeta(page))
elog(ERROR, "Relation is not a bloom index");
meta = BloomPageGetMeta(BufferGetPage(buffer));
if (meta->magickNumber != BLOOM_MAGICK_NUMBER)
elog(ERROR, "Relation is not a bloom index");
*opts = meta->opts;
UnlockReleaseBuffer(buffer);
index->rd_amcache = (void *) opts;
}
memcpy(&state->opts, index->rd_amcache, sizeof(state->opts));
state->sizeOfBloomTuple = BLOOMTUPLEHDRSZ +
sizeof(BloomSignatureWord) * state->opts.bloomLength;
}
/*
* Random generator copied from FreeBSD. Using own random generator here for
* two reasons:
*
* 1) In this case random numbers are used for on-disk storage. Usage of
* PostgreSQL number generator would obstruct it from all possible changes.
* 2) Changing seed of PostgreSQL random generator would be undesirable side
* effect.
*/
static int32 next;
static int32
myRand(void)
{
/*----------
* Compute x = (7^5 * x) mod (2^31 - 1)
* without overflowing 31 bits:
* (2^31 - 1) = 127773 * (7^5) + 2836
* From "Random number generators: good ones are hard to find",
* Park and Miller, Communications of the ACM, vol. 31, no. 10,
* October 1988, p. 1195.
*----------
*/
int32 hi,
lo,
x;
/* Must be in [1, 0x7ffffffe] range at this point. */
hi = next / 127773;
lo = next % 127773;
x = 16807 * lo - 2836 * hi;
if (x < 0)
x += 0x7fffffff;
next = x;
/* Transform to [0, 0x7ffffffd] range. */
return (x - 1);
}
static void
mySrand(uint32 seed)
{
next = seed;
/* Transform to [1, 0x7ffffffe] range. */
next = (next % 0x7ffffffe) + 1;
}
/*
* Add bits of given value to the signature.
*/
void
signValue(BloomState *state, BloomSignatureWord *sign, Datum value, int attno)
{
uint32 hashVal;
int nBit,
j;
/*
* init generator with "column's" number to get "hashed" seed for new
* value. We don't want to map the same numbers from different columns
* into the same bits!
*/
mySrand(attno);
/*
* Init hash sequence to map our value into bits. the same values in
* different columns will be mapped into different bits because of step
* above
*/
hashVal = DatumGetInt32(FunctionCall1Coll(&state->hashFn[attno], state->collations[attno], value));
mySrand(hashVal ^ myRand());
for (j = 0; j < state->opts.bitSize[attno]; j++)
{
/* prevent multiple evaluation in SETBIT macro */
nBit = myRand() % (state->opts.bloomLength * SIGNWORDBITS);
SETBIT(sign, nBit);
}
}
/*
* Make bloom tuple from values.
*/
BloomTuple *
BloomFormTuple(BloomState *state, ItemPointer iptr, Datum *values, bool *isnull)
{
int i;
BloomTuple *res = (BloomTuple *) palloc0(state->sizeOfBloomTuple);
res->heapPtr = *iptr;
/* Blooming each column */
for (i = 0; i < state->nColumns; i++)
{
/* skip nulls */
if (isnull[i])
continue;
signValue(state, res->sign, values[i], i);
}
return res;
}
/*
* Add new bloom tuple to the page. Returns true if new tuple was successfully
* added to the page. Returns false if it doesn't fit on the page.
*/
bool
BloomPageAddItem(BloomState *state, Page page, BloomTuple *tuple)
{
BloomTuple *itup;
BloomPageOpaque opaque;
Pointer ptr;
/* We shouldn't be pointed to an invalid page */
Assert(!PageIsNew(page) && !BloomPageIsDeleted(page));
/* Does new tuple fit on the page? */
if (BloomPageGetFreeSpace(state, page) < state->sizeOfBloomTuple)
return false;
/* Copy new tuple to the end of page */
opaque = BloomPageGetOpaque(page);
itup = BloomPageGetTuple(state, page, opaque->maxoff + 1);
memcpy((Pointer) itup, (Pointer) tuple, state->sizeOfBloomTuple);
/* Adjust maxoff and pd_lower */
opaque->maxoff++;
ptr = (Pointer) BloomPageGetTuple(state, page, opaque->maxoff + 1);
((PageHeader) page)->pd_lower = ptr - page;
/* Assert we didn't overrun available space */
Assert(((PageHeader) page)->pd_lower <= ((PageHeader) page)->pd_upper);
return true;
}
/*
* Allocate a new page (either by recycling, or by extending the index file)
* The returned buffer is already pinned and exclusive-locked
* Caller is responsible for initializing the page by calling BloomInitPage
*/
Buffer
BloomNewBuffer(Relation index)
{
Buffer buffer;
bool needLock;
/* First, try to get a page from FSM */
for (;;)
{
BlockNumber blkno = GetFreeIndexPage(index);
if (blkno == InvalidBlockNumber)
break;
buffer = ReadBuffer(index, blkno);
/*
* We have to guard against the possibility that someone else already
* recycled this page; the buffer may be locked if so.
*/
if (ConditionalLockBuffer(buffer))
{
Page page = BufferGetPage(buffer);
if (PageIsNew(page))
return buffer; /* OK to use, if never initialized */
if (BloomPageIsDeleted(page))
return buffer; /* OK to use */
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
}
/* Can't use it, so release buffer and try again */
ReleaseBuffer(buffer);
}
/* Must extend the file */
needLock = !RELATION_IS_LOCAL(index);
if (needLock)
LockRelationForExtension(index, ExclusiveLock);
buffer = ReadBuffer(index, P_NEW);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
if (needLock)
UnlockRelationForExtension(index, ExclusiveLock);
return buffer;
}
/*
* Initialize any page of a bloom index.
*/
void
BloomInitPage(Page page, uint16 flags)
{
BloomPageOpaque opaque;
PageInit(page, BLCKSZ, sizeof(BloomPageOpaqueData));
opaque = BloomPageGetOpaque(page);
memset(opaque, 0, sizeof(BloomPageOpaqueData));
opaque->flags = flags;
opaque->bloom_page_id = BLOOM_PAGE_ID;
}
/*
* Fill in metapage for bloom index.
*/
void
BloomFillMetapage(Relation index, Page metaPage)
{
BloomOptions *opts;
BloomMetaPageData *metadata;
/*
* Choose the index's options. If reloptions have been assigned, use
* those, otherwise create default options.
*/
opts = (BloomOptions *) index->rd_options;
if (!opts)
opts = makeDefaultBloomOptions();
/*
* Initialize contents of meta page, including a copy of the options,
* which are now frozen for the life of the index.
*/
BloomInitPage(metaPage, BLOOM_META);
metadata = BloomPageGetMeta(metaPage);
memset(metadata, 0, sizeof(BloomMetaPageData));
metadata->magickNumber = BLOOM_MAGICK_NUMBER;
metadata->opts = *opts;
((PageHeader) metaPage)->pd_lower += sizeof(BloomMetaPageData);
/* If this fails, probably FreeBlockNumberArray size calc is wrong: */
Assert(((PageHeader) metaPage)->pd_lower <= ((PageHeader) metaPage)->pd_upper);
}
/*
* Initialize metapage for bloom index.
*/
void
BloomInitMetapage(Relation index)
{
Buffer metaBuffer;
Page metaPage;
GenericXLogState *state;
/*
* Make a new page; since it is first page it should be associated with
* block number 0 (BLOOM_METAPAGE_BLKNO).
*/
metaBuffer = BloomNewBuffer(index);
Assert(BufferGetBlockNumber(metaBuffer) == BLOOM_METAPAGE_BLKNO);
/* Initialize contents of meta page */
state = GenericXLogStart(index);
metaPage = GenericXLogRegisterBuffer(state, metaBuffer,
GENERIC_XLOG_FULL_IMAGE);
BloomFillMetapage(index, metaPage);
GenericXLogFinish(state);
UnlockReleaseBuffer(metaBuffer);
}
/*
* Parse reloptions for bloom index, producing a BloomOptions struct.
*/
bytea *
bloptions(Datum reloptions, bool validate)
{
relopt_value *options;
int numoptions;
BloomOptions *rdopts;
/* Parse the user-given reloptions */
options = parseRelOptions(reloptions, validate, bl_relopt_kind, &numoptions);
rdopts = allocateReloptStruct(sizeof(BloomOptions), options, numoptions);
fillRelOptions((void *) rdopts, sizeof(BloomOptions), options, numoptions,
validate, bl_relopt_tab, lengthof(bl_relopt_tab));
/* Convert signature length from # of bits to # to words, rounding up */
rdopts->bloomLength = (rdopts->bloomLength + SIGNWORDBITS - 1) / SIGNWORDBITS;
return (bytea *) rdopts;
}
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