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| author | drh <> | 2021-07-15 19:29:43 +0000 |
|---|---|---|
| committer | drh <> | 2021-07-15 19:29:43 +0000 |
| commit | bb301231788a7ca2292005ecf8d924dbf122f2d2 (patch) | |
| tree | 14293aa7205fd4473513a252dab25e0e2be0639b /src/resolve.c | |
| parent | 480f5e3e6e70e803b35ddeab947988a89b0163a0 (diff) | |
| download | sqlite-bb301231788a7ca2292005ecf8d924dbf122f2d2.tar.gz sqlite-bb301231788a7ca2292005ecf8d924dbf122f2d2.zip | |
Attempt to omit ORDER BY clauses from FROM-clause subqueries if those ORDER BY
clauses do not affect the output. See
[forum:/forumpost/2d76f2bcf65d256a|forum thread 2d76f2bcf65d256a] for
discussion. This can help the query flattener in
some cases, resulting in faster query plans. The current implemention does
not always work.
FossilOrigin-Name: ef97c3e7c3ea2cf1a4db6591328fe7ce3f1d189afc2d578159135824ec89e620
Diffstat (limited to 'src/resolve.c')
| -rw-r--r-- | src/resolve.c | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/src/resolve.c b/src/resolve.c index 3bf84d322..955148a2f 100644 --- a/src/resolve.c +++ b/src/resolve.c @@ -1087,9 +1087,12 @@ static int resolveExprStep(Walker *pWalker, Expr *pExpr){ assert( pDef!=0 || IN_RENAME_OBJECT ); if( pNC2 && pDef ){ assert( SQLITE_FUNC_MINMAX==NC_MinMaxAgg ); + assert( SQLITE_FUNC_ANYORDER==NC_OrderAgg ); testcase( (pDef->funcFlags & SQLITE_FUNC_MINMAX)!=0 ); - pNC2->ncFlags |= NC_HasAgg | (pDef->funcFlags & SQLITE_FUNC_MINMAX); - + testcase( (pDef->funcFlags & SQLITE_FUNC_ANYORDER)!=0 ); + pNC2->ncFlags |= NC_HasAgg + | ((pDef->funcFlags^SQLITE_FUNC_ANYORDER) + & (SQLITE_FUNC_MINMAX|SQLITE_FUNC_ANYORDER)); } } pNC->ncFlags |= savedAllowFlags; @@ -1676,7 +1679,8 @@ static int resolveSelectStep(Walker *pWalker, Select *p){ pGroupBy = p->pGroupBy; if( pGroupBy || (sNC.ncFlags & NC_HasAgg)!=0 ){ assert( NC_MinMaxAgg==SF_MinMaxAgg ); - p->selFlags |= SF_Aggregate | (sNC.ncFlags&NC_MinMaxAgg); + assert( NC_OrderAgg==SF_OrderByReqd ); + p->selFlags |= SF_Aggregate | (sNC.ncFlags&(NC_MinMaxAgg|NC_OrderAgg)); }else{ sNC.ncFlags &= ~NC_AllowAgg; } @@ -1859,8 +1863,8 @@ int sqlite3ResolveExprNames( Walker w; if( pExpr==0 ) return SQLITE_OK; - savedHasAgg = pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin); - pNC->ncFlags &= ~(NC_HasAgg|NC_MinMaxAgg|NC_HasWin); + savedHasAgg = pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg); + pNC->ncFlags &= ~(NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg); w.pParse = pNC->pParse; w.xExprCallback = resolveExprStep; w.xSelectCallback = (pNC->ncFlags & NC_NoSelect) ? 0 : resolveSelectStep; @@ -1903,8 +1907,8 @@ int sqlite3ResolveExprListNames( w.xSelectCallback = resolveSelectStep; w.xSelectCallback2 = 0; w.u.pNC = pNC; - savedHasAgg = pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin); - pNC->ncFlags &= ~(NC_HasAgg|NC_MinMaxAgg|NC_HasWin); + savedHasAgg = pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg); + pNC->ncFlags &= ~(NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg); for(i=0; i<pList->nExpr; i++){ Expr *pExpr = pList->a[i].pExpr; if( pExpr==0 ) continue; @@ -1922,10 +1926,11 @@ int sqlite3ResolveExprListNames( assert( EP_Win==NC_HasWin ); testcase( pNC->ncFlags & NC_HasAgg ); testcase( pNC->ncFlags & NC_HasWin ); - if( pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin) ){ + if( pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg) ){ ExprSetProperty(pExpr, pNC->ncFlags & (NC_HasAgg|NC_HasWin) ); - savedHasAgg |= pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin); - pNC->ncFlags &= ~(NC_HasAgg|NC_MinMaxAgg|NC_HasWin); + savedHasAgg |= pNC->ncFlags & + (NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg); + pNC->ncFlags &= ~(NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg); } if( w.pParse->nErr>0 ) return WRC_Abort; } |