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Show LEFT and RIGHT JOIN processing in the EXPLAIN QUERY PLAN output.

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FossilOrigin-Name: d91faeffea5cf0585fb71e5311fdcc6b8be85c7e9c732050b4448e617c970101
This commit is contained in:
drh
2022-04-11 14:26:37 +00:00
parent 37259f4e6b
commit c583719b65
12 changed files with 45 additions and 40 deletions
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13
src/wherecode.c
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@@ -204,6 +204,9 @@ int sqlite3WhereExplainOneScan(
pLoop->u.vtab.idxNum, pLoop->u.vtab.idxStr);
}
#endif
if( pItem->fg.jointype & JT_LEFT ){
sqlite3_str_appendf(&str, " LEFT-JOIN");
}
#ifdef SQLITE_EXPLAIN_ESTIMATED_ROWS
if( pLoop->nOut>=10 ){
sqlite3_str_appendf(&str, " (~%llu rows)",
@@ -1150,7 +1153,7 @@ static void codeDeferredSeek(
pWInfo->bDeferredSeek = 1;
sqlite3VdbeAddOp3(v, OP_DeferredSeek, iIdxCur, 0, iCur);
if( (pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE)
if( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))
&& DbMaskAllZero(sqlite3ParseToplevel(pParse)->writeMask)
){
int i;
@@ -1502,7 +1505,7 @@ Bitmask sqlite3WhereCodeOneLoopStart(
** initialize a memory cell that records if this table matches any
** row of the left table of the join.
*/
assert( (pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE)
assert( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))
|| pLevel->iFrom>0 || (pTabItem[0].fg.jointype & JT_LEFT)==0
);
if( pLevel->iFrom>0 && (pTabItem[0].fg.jointype & JT_LEFT)!=0 ){
@@ -2140,7 +2143,7 @@ Bitmask sqlite3WhereCodeOneLoopStart(
/* Seek the table cursor, if required */
omitTable = (pLoop->wsFlags & WHERE_IDX_ONLY)!=0
&& (pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE)==0;
&& (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))==0;
if( omitTable ){
/* pIdx is a covering index. No need to access the main table. */
}else if( HasRowid(pIdx->pTable) ){
@@ -2174,7 +2177,7 @@ Bitmask sqlite3WhereCodeOneLoopStart(
** move forward to the next index.
** https://sqlite.org/src/info/4e8e4857d32d401f
*/
if( (pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE)==0 ){
if( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))==0 ){
whereIndexExprTrans(pIdx, iCur, iIdxCur, pWInfo);
}
@@ -2193,7 +2196,7 @@ Bitmask sqlite3WhereCodeOneLoopStart(
/* The following assert() is not a requirement, merely an observation:
** The OR-optimization doesn't work for the right hand table of
** a LEFT JOIN: */
assert( (pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE)==0 );
assert( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))==0 );
}
/* Record the instruction used to terminate the loop. */