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Avoid loading the entire record into memory for an sqlite3_preupdate_old() call that retrieves an IPK value.

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FossilOrigin-Name: 7f4de43733200beeb3ff0a70d51bbc68f5331895698ea95a82741cfd7bb66834
This commit is contained in:
dan
2024-11-04 16:59:02 +00:00
parent 88ef6be57d
commit 4bf24c8830
6 changed files with 121 additions and 59 deletions
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102
src/vdbeapi.c
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@@ -2197,60 +2197,64 @@ int sqlite3_preupdate_old(sqlite3 *db, int iIdx, sqlite3_value **ppValue){
goto preupdate_old_out;
}
/* If the old.* record has not yet been loaded into memory, do so now. */
if( p->pUnpacked==0 ){
u32 nRec;
u8 *aRec;
assert( p->pCsr->eCurType==CURTYPE_BTREE );
nRec = sqlite3BtreePayloadSize(p->pCsr->uc.pCursor);
aRec = sqlite3DbMallocRaw(db, nRec);
if( !aRec ) goto preupdate_old_out;
rc = sqlite3BtreePayload(p->pCsr->uc.pCursor, 0, nRec, aRec);
if( rc==SQLITE_OK ){
p->pUnpacked = vdbeUnpackRecord(&p->keyinfo, nRec, aRec);
if( !p->pUnpacked ) rc = SQLITE_NOMEM;
}
if( rc!=SQLITE_OK ){
sqlite3DbFree(db, aRec);
goto preupdate_old_out;
}
p->aRecord = aRec;
}
pMem = *ppValue = &p->pUnpacked->aMem[iIdx];
if( iIdx==p->pTab->iPKey ){
*ppValue = pMem = &p->oldipk;
sqlite3VdbeMemSetInt64(pMem, p->iKey1);
}else if( iIdx>=p->pUnpacked->nField ){
/* This occurs when the table has been extended using ALTER TABLE
** ADD COLUMN. The value to return is the default value of the column. */
Column *pCol = &p->pTab->aCol[iIdx];
if( pCol->iDflt>0 ){
if( p->apDflt==0 ){
int nByte = sizeof(sqlite3_value*)*p->pTab->nCol;
p->apDflt = (sqlite3_value**)sqlite3DbMallocZero(db, nByte);
if( p->apDflt==0 ) goto preupdate_old_out;
}else{
/* If the old.* record has not yet been loaded into memory, do so now. */
if( p->pUnpacked==0 ){
u32 nRec;
u8 *aRec;
assert( p->pCsr->eCurType==CURTYPE_BTREE );
nRec = sqlite3BtreePayloadSize(p->pCsr->uc.pCursor);
aRec = sqlite3DbMallocRaw(db, nRec);
if( !aRec ) goto preupdate_old_out;
rc = sqlite3BtreePayload(p->pCsr->uc.pCursor, 0, nRec, aRec);
if( rc==SQLITE_OK ){
p->pUnpacked = vdbeUnpackRecord(&p->keyinfo, nRec, aRec);
if( !p->pUnpacked ) rc = SQLITE_NOMEM;
}
if( p->apDflt[iIdx]==0 ){
sqlite3_value *pVal = 0;
Expr *pDflt;
assert( p->pTab!=0 && IsOrdinaryTable(p->pTab) );
pDflt = p->pTab->u.tab.pDfltList->a[pCol->iDflt-1].pExpr;
rc = sqlite3ValueFromExpr(db, pDflt, ENC(db), pCol->affinity, &pVal);
if( rc==SQLITE_OK && pVal==0 ){
rc = SQLITE_CORRUPT_BKPT;
}
p->apDflt[iIdx] = pVal;
if( rc!=SQLITE_OK ){
sqlite3DbFree(db, aRec);
goto preupdate_old_out;
}
*ppValue = p->apDflt[iIdx];
}else{
*ppValue = (sqlite3_value *)columnNullValue();
p->aRecord = aRec;
}
}else if( p->pTab->aCol[iIdx].affinity==SQLITE_AFF_REAL ){
if( pMem->flags & (MEM_Int|MEM_IntReal) ){
testcase( pMem->flags & MEM_Int );
testcase( pMem->flags & MEM_IntReal );
sqlite3VdbeMemRealify(pMem);
pMem = *ppValue = &p->pUnpacked->aMem[iIdx];
if( iIdx>=p->pUnpacked->nField ){
/* This occurs when the table has been extended using ALTER TABLE
** ADD COLUMN. The value to return is the default value of the column. */
Column *pCol = &p->pTab->aCol[iIdx];
if( pCol->iDflt>0 ){
if( p->apDflt==0 ){
int nByte = sizeof(sqlite3_value*)*p->pTab->nCol;
p->apDflt = (sqlite3_value**)sqlite3DbMallocZero(db, nByte);
if( p->apDflt==0 ) goto preupdate_old_out;
}
if( p->apDflt[iIdx]==0 ){
sqlite3_value *pVal = 0;
Expr *pDflt;
assert( p->pTab!=0 && IsOrdinaryTable(p->pTab) );
pDflt = p->pTab->u.tab.pDfltList->a[pCol->iDflt-1].pExpr;
rc = sqlite3ValueFromExpr(db, pDflt, ENC(db), pCol->affinity, &pVal);
if( rc==SQLITE_OK && pVal==0 ){
rc = SQLITE_CORRUPT_BKPT;
}
p->apDflt[iIdx] = pVal;
}
*ppValue = p->apDflt[iIdx];
}else{
*ppValue = (sqlite3_value *)columnNullValue();
}
}else if( p->pTab->aCol[iIdx].affinity==SQLITE_AFF_REAL ){
if( pMem->flags & (MEM_Int|MEM_IntReal) ){
testcase( pMem->flags & MEM_Int );
testcase( pMem->flags & MEM_IntReal );
sqlite3VdbeMemRealify(pMem);
}
}
}