postgresql/contrib/bloom/blutils.c
Tom Lane d6c9e05cb7 Fix assorted bugs in contrib/bloom.
In blinsert(), cope with the possibility that a page we pull from the
notFullPage list is marked BLOOM_DELETED.  This could happen if VACUUM
recently marked it deleted but hasn't (yet) updated the metapage.
We can re-use such a page safely, but we *must* reinitialize it so that
it's no longer marked deleted.

Fix blvacuum() so that it updates the notFullPage list even if it's
going to update it to empty.  The previous "optimization" of skipping
the update seems pretty dubious, since it means that the next blinsert()
will uselessly visit whatever pages we left in the list.

Uniformly treat PageIsNew pages the same as deleted pages.  This should
allow proper recovery if a crash occurs just after relation extension.

Properly use vacuum_delay_point, not assorted ad-hoc CHECK_FOR_INTERRUPTS
calls, in the blvacuum() main loop.

Fix broken tuple-counting logic: blvacuum.c counted the number of live
index tuples over again in each scan, leading to VACUUM VERBOSE reporting
some multiple of the actual number of surviving index tuples after any
vacuum that removed any tuples (since they'd be counted in blvacuum, maybe
more than once, and then again in blvacuumcleanup, without ever zeroing the
counter).  It's sufficient to count them in blvacuumcleanup.

stats->estimated_count is a boolean, not a counter, and we don't want
to set it true, so don't add tuple counts to it.

Add a couple of Asserts that we don't overrun available space on a bloom
page.  I don't think there's any bug there today, but the way the
FreeBlockNumberArray size calculation is set up is scarily fragile, and
BloomPageGetFreeSpace isn't much better.  The Asserts should help catch
any future mistakes.

Per investigation of a report from Jeff Janes.  I think the first item
above may explain his report; the other changes were things I noticed
while casting about for an explanation.

Report: <CAMkU=1xEUuBphDwDmB1WjN4+td4kpnEniFaTBxnk1xzHCw8_OQ@mail.gmail.com>
2016-08-13 22:24:48 -04:00

486 lines
12 KiB
C

/*-------------------------------------------------------------------------
*
* blutils.c
* Bloom index utilities.
*
* Portions Copyright (c) 2016, 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[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->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->amvalidate = blvalidate;
amroutine->ambeginscan = blbeginscan;
amroutine->amrescan = blrescan;
amroutine->amgettuple = NULL;
amroutine->amgetbitmap = blgetbitmap;
amroutine->amendscan = blendscan;
amroutine->ammarkpos = NULL;
amroutine->amrestrpos = 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);
}
/* 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(FunctionCall1(&state->hashFn[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 BloomInitBuffer
*/
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;
}