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-rw-r--r--src/select.c141
1 files changed, 121 insertions, 20 deletions
diff --git a/src/select.c b/src/select.c
index 766f67f8d..0f83bbb36 100644
--- a/src/select.c
+++ b/src/select.c
@@ -771,6 +771,88 @@ static KeyInfo *keyInfoFromExprList(Parse *pParse, ExprList *pList){
return pInfo;
}
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+/*
+** Name of the connection operator, used for error messages.
+*/
+static const char *selectOpName(int id){
+ char *z;
+ switch( id ){
+ case TK_ALL: z = "UNION ALL"; break;
+ case TK_INTERSECT: z = "INTERSECT"; break;
+ case TK_EXCEPT: z = "EXCEPT"; break;
+ default: z = "UNION"; break;
+ }
+ return z;
+}
+#endif /* SQLITE_OMIT_COMPOUND_SELECT */
+
+#ifndef SQLITE_OMIT_EXPLAIN
+/*
+** Unless an "EXPLAIN QUERY PLAN" command is being processed, this function
+** is a no-op. Otherwise, it adds a single row of output to the EQP result,
+** where the caption is of the form:
+**
+** "USE TEMP B-TREE FOR xxx"
+**
+** where xxx is one of "DISTINCT", "ORDER BY" or "GROUP BY". Exactly which
+** is determined by the zUsage argument.
+*/
+static void explainTempTable(Parse *pParse, const char *zUsage){
+ if( pParse->explain==2 ){
+ Vdbe *v = pParse->pVdbe;
+ char *zMsg = sqlite3MPrintf(pParse->db, "USE TEMP B-TREE FOR %s", zUsage);
+ sqlite3VdbeAddOp4(v, OP_Explain, pParse->iSelectId, 0, 0, zMsg, P4_DYNAMIC);
+ }
+}
+
+/*
+** Unless an "EXPLAIN QUERY PLAN" command is being processed, this function
+** is a no-op. Otherwise, it adds a single row of output to the EQP result,
+** where the caption is of one of the two forms:
+**
+** "COMPOSITE SUBQUERIES iSub1 and iSub2 (op)"
+** "COMPOSITE SUBQUERIES iSub1 and iSub2 USING TEMP B-TREE (op)"
+**
+** where iSub1 and iSub2 are the integers passed as the corresponding
+** function parameters, and op is the text representation of the parameter
+** of the same name. The parameter "op" must be one of TK_UNION, TK_EXCEPT,
+** TK_INTERSECT or TK_ALL. The first form is used if argument bUseTmp is
+** false, or the second form if it is true.
+*/
+static void explainComposite(
+ Parse *pParse, /* Parse context */
+ int op, /* One of TK_UNION, TK_EXCEPT etc. */
+ int iSub1, /* Subquery id 1 */
+ int iSub2, /* Subquery id 2 */
+ int bUseTmp /* True if a temp table was used */
+){
+ assert( op==TK_UNION || op==TK_EXCEPT || op==TK_INTERSECT || op==TK_ALL );
+ if( pParse->explain==2 ){
+ Vdbe *v = pParse->pVdbe;
+ char *zMsg = sqlite3MPrintf(
+ pParse->db, "COMPOUND SUBQUERIES %d AND %d %s(%s)", iSub1, iSub2,
+ bUseTmp?"USING TEMP B-TREE ":"", selectOpName(op)
+ );
+ sqlite3VdbeAddOp4(v, OP_Explain, pParse->iSelectId, 0, 0, zMsg, P4_DYNAMIC);
+ }
+}
+
+/*
+** Assign expression b to lvalue a. A second, no-op, version of this macro
+** is provided when SQLITE_OMIT_EXPLAIN is defined. This allows the code
+** in sqlite3Select() to assign values to structure member variables that
+** only exist if SQLITE_OMIT_EXPLAIN is not defined without polluting the
+** code with #ifndef directives.
+*/
+# define explainSetInteger(a, b) a = b
+
+#else
+/* No-op versions of the explainXXX() functions and macros. */
+# define explainTempTable(y,z)
+# define explainComposite(v,w,x,y,z)
+# define explainSetInteger(y,z)
+#endif
/*
** If the inner loop was generated using a non-null pOrderBy argument,
@@ -1118,22 +1200,6 @@ static void generateColumnNames(
generateColumnTypes(pParse, pTabList, pEList);
}
-#ifndef SQLITE_OMIT_COMPOUND_SELECT
-/*
-** Name of the connection operator, used for error messages.
-*/
-static const char *selectOpName(int id){
- char *z;
- switch( id ){
- case TK_ALL: z = "UNION ALL"; break;
- case TK_INTERSECT: z = "INTERSECT"; break;
- case TK_EXCEPT: z = "EXCEPT"; break;
- default: z = "UNION"; break;
- }
- return z;
-}
-#endif /* SQLITE_OMIT_COMPOUND_SELECT */
-
/*
** Given a an expression list (which is really the list of expressions
** that form the result set of a SELECT statement) compute appropriate
@@ -1467,6 +1533,10 @@ static int multiSelect(
SelectDest dest; /* Alternative data destination */
Select *pDelete = 0; /* Chain of simple selects to delete */
sqlite3 *db; /* Database connection */
+#ifndef SQLITE_OMIT_EXPLAIN
+ int iSub1; /* EQP id of left-hand query */
+ int iSub2; /* EQP id of right-hand query */
+#endif
/* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs. Only
** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
@@ -1527,6 +1597,7 @@ static int multiSelect(
assert( !pPrior->pLimit );
pPrior->pLimit = p->pLimit;
pPrior->pOffset = p->pOffset;
+ explainSetInteger(iSub1, pParse->iNextSelectId);
rc = sqlite3Select(pParse, pPrior, &dest);
p->pLimit = 0;
p->pOffset = 0;
@@ -1540,6 +1611,7 @@ static int multiSelect(
addr = sqlite3VdbeAddOp1(v, OP_IfZero, p->iLimit);
VdbeComment((v, "Jump ahead if LIMIT reached"));
}
+ explainSetInteger(iSub2, pParse->iNextSelectId);
rc = sqlite3Select(pParse, p, &dest);
testcase( rc!=SQLITE_OK );
pDelete = p->pPrior;
@@ -1587,6 +1659,7 @@ static int multiSelect(
*/
assert( !pPrior->pOrderBy );
sqlite3SelectDestInit(&uniondest, priorOp, unionTab);
+ explainSetInteger(iSub1, pParse->iNextSelectId);
rc = sqlite3Select(pParse, pPrior, &uniondest);
if( rc ){
goto multi_select_end;
@@ -1606,6 +1679,7 @@ static int multiSelect(
pOffset = p->pOffset;
p->pOffset = 0;
uniondest.eDest = op;
+ explainSetInteger(iSub2, pParse->iNextSelectId);
rc = sqlite3Select(pParse, p, &uniondest);
testcase( rc!=SQLITE_OK );
/* Query flattening in sqlite3Select() might refill p->pOrderBy.
@@ -1671,6 +1745,7 @@ static int multiSelect(
/* Code the SELECTs to our left into temporary table "tab1".
*/
sqlite3SelectDestInit(&intersectdest, SRT_Union, tab1);
+ explainSetInteger(iSub1, pParse->iNextSelectId);
rc = sqlite3Select(pParse, pPrior, &intersectdest);
if( rc ){
goto multi_select_end;
@@ -1687,6 +1762,7 @@ static int multiSelect(
pOffset = p->pOffset;
p->pOffset = 0;
intersectdest.iParm = tab2;
+ explainSetInteger(iSub2, pParse->iNextSelectId);
rc = sqlite3Select(pParse, p, &intersectdest);
testcase( rc!=SQLITE_OK );
pDelete = p->pPrior;
@@ -1723,6 +1799,8 @@ static int multiSelect(
}
}
+ explainComposite(pParse, p->op, iSub1, iSub2, p->op!=TK_ALL);
+
/* Compute collating sequences used by
** temporary tables needed to implement the compound select.
** Attach the KeyInfo structure to all temporary tables.
@@ -2066,6 +2144,10 @@ static int multiSelectOrderBy(
ExprList *pOrderBy; /* The ORDER BY clause */
int nOrderBy; /* Number of terms in the ORDER BY clause */
int *aPermute; /* Mapping from ORDER BY terms to result set columns */
+#ifndef SQLITE_OMIT_EXPLAIN
+ int iSub1; /* EQP id of left-hand query */
+ int iSub2; /* EQP id of right-hand query */
+#endif
assert( p->pOrderBy!=0 );
assert( pKeyDup==0 ); /* "Managed" code needs this. Ticket #3382. */
@@ -2219,6 +2301,7 @@ static int multiSelectOrderBy(
*/
VdbeNoopComment((v, "Begin coroutine for left SELECT"));
pPrior->iLimit = regLimitA;
+ explainSetInteger(iSub1, pParse->iNextSelectId);
sqlite3Select(pParse, pPrior, &destA);
sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofA);
sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
@@ -2233,6 +2316,7 @@ static int multiSelectOrderBy(
savedOffset = p->iOffset;
p->iLimit = regLimitB;
p->iOffset = 0;
+ explainSetInteger(iSub2, pParse->iNextSelectId);
sqlite3Select(pParse, p, &destB);
p->iLimit = savedLimit;
p->iOffset = savedOffset;
@@ -2363,6 +2447,7 @@ static int multiSelectOrderBy(
/*** TBD: Insert subroutine calls to close cursors on incomplete
**** subqueries ****/
+ explainComposite(pParse, p->op, iSub1, iSub2, 0);
return SQLITE_OK;
}
#endif
@@ -3590,6 +3675,11 @@ int sqlite3Select(
int iEnd; /* Address of the end of the query */
sqlite3 *db; /* The database connection */
+#ifndef SQLITE_OMIT_EXPLAIN
+ int iRestoreSelectId = pParse->iSelectId;
+ pParse->iSelectId = pParse->iNextSelectId++;
+#endif
+
db = pParse->db;
if( p==0 || db->mallocFailed || pParse->nErr ){
return 1;
@@ -3661,6 +3751,7 @@ int sqlite3Select(
}else{
sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
assert( pItem->isPopulated==0 );
+ explainSetInteger(pItem->iSelectId, pParse->iNextSelectId);
sqlite3Select(pParse, pSub, &dest);
pItem->isPopulated = 1;
}
@@ -3696,10 +3787,12 @@ int sqlite3Select(
mxSelect = db->aLimit[SQLITE_LIMIT_COMPOUND_SELECT];
if( mxSelect && cnt>mxSelect ){
sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
- return 1;
+ goto select_end;
}
}
- return multiSelect(pParse, p, pDest);
+ rc = multiSelect(pParse, p, pDest);
+ explainSetInteger(pParse->iSelectId, iRestoreSelectId);
+ return rc;
}
#endif
@@ -3711,7 +3804,6 @@ int sqlite3Select(
p->pGroupBy = sqlite3ExprListDup(db, p->pEList, 0);
pGroupBy = p->pGroupBy;
p->selFlags &= ~SF_Distinct;
- isDistinct = 0;
}
/* If there is both a GROUP BY and an ORDER BY clause and they are
@@ -3758,7 +3850,7 @@ int sqlite3Select(
/* Open a virtual index to use for the distinct set.
*/
- if( isDistinct ){
+ if( p->selFlags & SF_Distinct ){
KeyInfo *pKeyInfo;
assert( isAgg || pGroupBy );
distinct = pParse->nTab++;
@@ -3917,6 +4009,9 @@ int sqlite3Select(
int nCol;
int nGroupBy;
+ explainTempTable(pParse,
+ isDistinct && !(p->selFlags&SF_Distinct)?"DISTINCT":"GROUP BY");
+
groupBySort = 1;
nGroupBy = pGroupBy->nExpr;
nCol = nGroupBy + 1;
@@ -4178,10 +4273,15 @@ int sqlite3Select(
} /* endif aggregate query */
+ if( distinct>=0 ){
+ explainTempTable(pParse, "DISTINCT");
+ }
+
/* If there is an ORDER BY clause, then we need to sort the results
** and send them to the callback one by one.
*/
if( pOrderBy ){
+ explainTempTable(pParse, "ORDER BY");
generateSortTail(pParse, p, v, pEList->nExpr, pDest);
}
@@ -4198,6 +4298,7 @@ int sqlite3Select(
** successful coding of the SELECT.
*/
select_end:
+ explainSetInteger(pParse->iSelectId, iRestoreSelectId);
/* Identify column names if results of the SELECT are to be output.
*/
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-22 18:00:58 +0000