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When a sub-transaction is released, if no pages required by containing sub-transactions were journaled, truncate the statement journal. This might prevent out-of-control statement journal growth in some cases.

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FossilOrigin-Name: e36327fb22db08763a82fb517407ff5ab0dbc053953098033e7e50796a777810
This commit is contained in:
dan
2021-02-22 15:44:45 +00:00
parent 7601294ad3
commit f43fef29bb
4 changed files with 46 additions and 31 deletions
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13
src/pager.c
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@@ -435,6 +435,7 @@ struct PagerSavepoint {
Bitvec *pInSavepoint; /* Set of pages in this savepoint */
Pgno nOrig; /* Original number of pages in file */
Pgno iSubRec; /* Index of first record in sub-journal */
int bTruncateOnRelease; /* If stmt journal may be truncated on RELEASE */
#ifndef SQLITE_OMIT_WAL
u32 aWalData[WAL_SAVEPOINT_NDATA]; /* WAL savepoint context */
#endif
@@ -1070,6 +1071,9 @@ static int subjRequiresPage(PgHdr *pPg){
for(i=0; i<pPager->nSavepoint; i++){
p = &pPager->aSavepoint[i];
if( p->nOrig>=pgno && 0==sqlite3BitvecTestNotNull(p->pInSavepoint, pgno) ){
for(i=i+1; i<pPager->nSavepoint; i++){
pPager->aSavepoint[i].bTruncateOnRelease = 0;
}
return 1;
}
}
@@ -6848,6 +6852,7 @@ static SQLITE_NOINLINE int pagerOpenSavepoint(Pager *pPager, int nSavepoint){
}
aNew[ii].iSubRec = pPager->nSubRec;
aNew[ii].pInSavepoint = sqlite3BitvecCreate(pPager->dbSize);
aNew[ii].bTruncateOnRelease = 1;
if( !aNew[ii].pInSavepoint ){
return SQLITE_NOMEM_BKPT;
}
@@ -6929,13 +6934,15 @@ int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint){
/* If this is a release of the outermost savepoint, truncate
** the sub-journal to zero bytes in size. */
if( op==SAVEPOINT_RELEASE ){
if( nNew==0 && isOpen(pPager->sjfd) ){
PagerSavepoint *pRel = &pPager->aSavepoint[nNew];
if( pRel->bTruncateOnRelease && isOpen(pPager->sjfd) ){
/* Only truncate if it is an in-memory sub-journal. */
if( sqlite3JournalIsInMemory(pPager->sjfd) ){
rc = sqlite3OsTruncate(pPager->sjfd, 0);
i64 sz = (pPager->pageSize+4)*pRel->iSubRec;
rc = sqlite3OsTruncate(pPager->sjfd, sz);
assert( rc==SQLITE_OK );
}
pPager->nSubRec = 0;
pPager->nSubRec = pRel->iSubRec;
}
}
/* Else this is a rollback operation, playback the specified savepoint.