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It is not necessary to de-ephermeralize the output registers in the

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OP_ResultRow opcode.  Omit that step for a size reduction and performance
increase.

FossilOrigin-Name: 8a07745aed1d0a4eead55d43f1923597b12371f307ecf5bc19c5a1db9a107a50
This commit is contained in:
drh
2022-04-01 20:19:36 +00:00
parent 35e9e350ca
commit 3b8b5be3b7
3 changed files with 22 additions and 35 deletions
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43
src/vdbe.c
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@@ -1549,45 +1549,32 @@ case OP_FkCheck: {
** the result row.
*/
case OP_ResultRow: {
Mem *pMem;
int i;
assert( p->nResColumn==pOp->p2 );
assert( pOp->p1>0 || CORRUPT_DB );
assert( pOp->p1+pOp->p2<=(p->nMem+1 - p->nCursor)+1 );
/* Invalidate all ephemeral cursor row caches */
p->cacheCtr = (p->cacheCtr + 2)|1;
/* Make sure the results of the current row are \000 terminated
** and have an assigned type. The results are de-ephemeralized as
** a side effect.
*/
pMem = p->pResultSet = &aMem[pOp->p1];
for(i=0; i<pOp->p2; i++){
assert( memIsValid(&pMem[i]) );
Deephemeralize(&pMem[i]);
assert( (pMem[i].flags & MEM_Ephem)==0
|| (pMem[i].flags & (MEM_Str|MEM_Blob))==0 );
sqlite3VdbeMemNulTerminate(&pMem[i]);
REGISTER_TRACE(pOp->p1+i, &pMem[i]);
p->pResultSet = &aMem[pOp->p1];
#ifdef SQLITE_DEBUG
/* The registers in the result will not be used again when the
** prepared statement restarts. This is because sqlite3_column()
** APIs might have caused type conversions of made other changes to
** the register values. Therefore, we can go ahead and break any
** OP_SCopy dependencies. */
pMem[i].pScopyFrom = 0;
#endif
{
Mem *pMem = p->pResultSet;
int i;
for(i=0; i<pOp->p2; i++){
assert( memIsValid(&pMem[i]) );
REGISTER_TRACE(pOp->p1+i, &pMem[i]);
/* The registers in the result will not be used again when the
** prepared statement restarts. This is because sqlite3_column()
** APIs might have caused type conversions of made other changes to
** the register values. Therefore, we can go ahead and break any
** OP_SCopy dependencies. */
pMem[i].pScopyFrom = 0;
}
}
#endif
if( db->mallocFailed ) goto no_mem;
if( db->mTrace & SQLITE_TRACE_ROW ){
db->trace.xV2(SQLITE_TRACE_ROW, db->pTraceArg, p, 0);
}
/* Return SQLITE_ROW
*/
p->pc = (int)(pOp - aOp) + 1;
rc = SQLITE_ROW;
goto vdbe_return;