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Fix multiple issues with the ORDER BY LIMIT optimization. This is the

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proposed resolution to ticket [9936b2fa443fec03ff25].

FossilOrigin-Name: 206720129ed2fa8875a286266d05b99fb2caf8671e4b74b26a6286a2073fcd8b
This commit is contained in:
drh
2018-09-08 20:09:46 +00:00
parent c93c614543
commit 6ee5a7b481
6 changed files with 97 additions and 27 deletions
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15
src/select.c
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@@ -68,8 +68,8 @@ struct SortCtx {
int labelBkOut; /* Start label for the block-output subroutine */
int addrSortIndex; /* Address of the OP_SorterOpen or OP_OpenEphemeral */
int labelDone; /* Jump here when done, ex: LIMIT reached */
int labelOBLopt; /* Jump here when sorter is full */
u8 sortFlags; /* Zero or more SORTFLAG_* bits */
u8 bOrderedInnerLoop; /* ORDER BY correctly sorts the inner loop */
#ifdef SQLITE_ENABLE_SORTER_REFERENCES
u8 nDefer; /* Number of valid entries in aDefer[] */
struct DeferredCsr {
@@ -693,10 +693,10 @@ static void pushOntoSorter(
** than LIMIT+OFFSET items in the sorter.
**
** If the new record does not need to be inserted into the sorter,
** jump to the next iteration of the loop. Or, if the
** pSort->bOrderedInnerLoop flag is set to indicate that the inner
** loop delivers items in sorted order, jump to the next iteration
** of the outer loop.
** jump to the next iteration of the loop. If the pSort->labelOBLopt
** value is not zero, then it is a label of where to jump. Otherwise,
** just bypass the row insert logic. See the header comment on the
** sqlite3WhereOrderByLimitOptLabel() function for additional info.
*/
int iCsr = pSort->iECursor;
sqlite3VdbeAddOp2(v, OP_IfNotZero, iLimit, sqlite3VdbeCurrentAddr(v)+4);
@@ -718,9 +718,8 @@ static void pushOntoSorter(
sqlite3VdbeAddOp4Int(v, op, pSort->iECursor, regRecord,
regBase+nOBSat, nBase-nOBSat);
if( iSkip ){
assert( pSort->bOrderedInnerLoop==0 || pSort->bOrderedInnerLoop==1 );
sqlite3VdbeChangeP2(v, iSkip,
sqlite3VdbeCurrentAddr(v) + pSort->bOrderedInnerLoop);
pSort->labelOBLopt ? pSort->labelOBLopt : sqlite3VdbeCurrentAddr(v));
}
}
@@ -6060,7 +6059,7 @@ int sqlite3Select(
}
if( sSort.pOrderBy ){
sSort.nOBSat = sqlite3WhereIsOrdered(pWInfo);
sSort.bOrderedInnerLoop = sqlite3WhereOrderedInnerLoop(pWInfo);
sSort.labelOBLopt = sqlite3WhereOrderByLimitOptLabel(pWInfo);
if( sSort.nOBSat==sSort.pOrderBy->nExpr ){
sSort.pOrderBy = 0;
}