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Avoid allocating a large object on the stack in the incremental merge code. Use sqlite3_malloc() instead.

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FossilOrigin-Name: 36ae510de45be44efd34cff242d02fb21b7419ac
This commit is contained in:
dan
2012-03-14 12:17:40 +00:00
parent 8af1fc721e
commit a2af0aecdb
3 changed files with 37 additions and 33 deletions
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56
ext/fts3/fts3_write.c
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@ -25,7 +25,7 @@
#include <stdlib.h>
#define FTS_MAX_APPENDABLE_HEIGHT 10
#define FTS_MAX_APPENDABLE_HEIGHT 16
/*
** When full-text index nodes are loaded from disk, the buffer that they
@ -4164,17 +4164,15 @@ static int fts3Incrmerge(Fts3Table *p, int nMerge, int nMin){
while( rc==SQLITE_OK && nRem>0 ){
sqlite3_int64 iAbsLevel; /* Absolute level number to work on */
sqlite3_stmt *pFindLevel = 0; /* SQL used to determine iAbsLevel */
Fts3MultiSegReader csr; /* Cursor used to read input data */
Fts3SegFilter filter; /* Filter used with cursor csr */
IncrmergeWriter writer; /* Writer object */
memset(&writer, 0, sizeof(IncrmergeWriter));
Fts3MultiSegReader *pCsr; /* Cursor used to read input data */
Fts3SegFilter *pFilter; /* Filter used with cursor pCsr */
IncrmergeWriter *pWriter; /* Writer object */
const int nAlloc = sizeof(*pCsr) + sizeof(*pFilter) + sizeof(*pWriter);
/* Determine which level to merge segments from. Any level, from any
** prefix or language index may be selected. Stack variable iAbsLevel
** is set to the absolute level number of the level to merge from. */
rc = fts3SqlStmt(p, SQL_FIND_MERGE_LEVEL, &pFindLevel, 0);
if( rc!=SQLITE_OK ) return rc;
sqlite3_bind_int(pFindLevel, 1, nMin);
if( sqlite3_step(pFindLevel)!=SQLITE_ROW ){
return sqlite3_reset(pFindLevel);
@ -4183,35 +4181,41 @@ static int fts3Incrmerge(Fts3Table *p, int nMerge, int nMin){
rc = sqlite3_reset(pFindLevel);
if( rc!=SQLITE_OK ) return rc;
/* Allocate space for the cursor, filter and writer objects */
pWriter = (IncrmergeWriter *)sqlite3_malloc(nAlloc);
if( !pWriter ) return SQLITE_NOMEM;
memset(pWriter, 0, nAlloc);
pFilter = (Fts3SegFilter *)&pWriter[1];
pCsr = (Fts3MultiSegReader *)&pFilter[1];
/* Open a cursor to iterate through the contents of indexes 0 and 1 of
** the selected absolute level. */
rc = fts3IncrmergeCsr(p, iAbsLevel, &csr);
if( rc!=SQLITE_OK ) return rc;
memset(&filter, 0, sizeof(Fts3SegFilter));
filter.flags = FTS3_SEGMENT_REQUIRE_POS;
pFilter->flags = FTS3_SEGMENT_REQUIRE_POS;
rc = fts3IncrmergeCsr(p, iAbsLevel, pCsr);
rc = sqlite3Fts3SegReaderStart(p, &csr, &filter);
assert( rc!=SQLITE_ABORT );
if( SQLITE_ROW==(rc = sqlite3Fts3SegReaderStep(p, &csr)) ){
rc = fts3IncrmergeWriter(p, iAbsLevel, csr.zTerm, csr.nTerm, &writer);
if( rc==SQLITE_OK ){
do {
rc = fts3IncrmergeAppend(p, &writer, &csr);
if( rc==SQLITE_OK ) rc = sqlite3Fts3SegReaderStep(p, &csr);
if( writer.nWork>=nRem && rc==SQLITE_ROW ) rc = SQLITE_OK;
}while( rc==SQLITE_ROW );
if( rc==SQLITE_OK ){
rc = sqlite3Fts3SegReaderStart(p, pCsr, pFilter);
if( SQLITE_ROW==(rc = sqlite3Fts3SegReaderStep(p, pCsr)) ){
rc = fts3IncrmergeWriter(p, iAbsLevel, pCsr->zTerm,pCsr->nTerm,pWriter);
if( rc==SQLITE_OK ){
do {
rc = fts3IncrmergeAppend(p, pWriter, pCsr);
if( rc==SQLITE_OK ) rc = sqlite3Fts3SegReaderStep(p, pCsr);
if( pWriter->nWork>=nRem && rc==SQLITE_ROW ) rc = SQLITE_OK;
}while( rc==SQLITE_ROW );
}
}
}
assert( rc!=SQLITE_ABORT );
fts3IncrmergeRelease(p, &writer, &rc);
nRem -= (1 + writer.nWork);
fts3IncrmergeRelease(p, pWriter, &rc);
nRem -= (1 + pWriter->nWork);
/* Update or delete the input segments */
if( rc==SQLITE_OK ){
rc = fts3IncrmergeChomp(p, iAbsLevel, &csr);
rc = fts3IncrmergeChomp(p, iAbsLevel, pCsr);
}
sqlite3Fts3SegReaderFinish(&csr);
sqlite3Fts3SegReaderFinish(pCsr);
sqlite3_free(pWriter);
}
return rc;