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Get ORDER BY working for recursive queries.

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FossilOrigin-Name: 37b343b01841b338954ddfa9b76d92aa50037aec
This commit is contained in:
drh
2014-01-22 17:28:35 +00:00
parent 781def29c7
commit fe1c6bb9c2
5 changed files with 143 additions and 60 deletions
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135
src/select.c
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@@ -581,10 +581,8 @@ static void selectInnerLoop(
pDest->iSdst = pParse->nMem+1;
pDest->nSdst = nResultCol;
pParse->nMem += nResultCol;
if( eDest==SRT_Queue ) pParse->nMem++;
}else{
assert( pDest->nSdst==nResultCol );
assert( eDest!=SRT_Queue );
}
regResult = pDest->iSdst;
if( srcTab>=0 ){
@@ -664,30 +662,10 @@ static void selectInnerLoop(
** table iParm.
*/
#ifndef SQLITE_OMIT_COMPOUND_SELECT
#ifndef SQLITE_OMIT_CTE
case SRT_Queue: {
sqlite3VdbeAddOp2(v, OP_Sequence, iParm, regResult+nResultCol);
nResultCol++;
/* Fall through into SRT_Union */
}
case SRT_DistQueue:
#endif /* SQLITE_OMIT_CTE */
case SRT_Union: {
int r1;
r1 = sqlite3GetTempReg(pParse);
sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r1);
#ifndef SQLITE_OMIT_CTE
if( eDest==SRT_DistQueue ){
/* If the destination is DistQueue, then cursor (iParm+1) is open
** on a second ephemeral index that holds all values every previously
** added to the queue. Only add this new value if it has never before
** been added */
int addr = sqlite3VdbeCurrentAddr(v) + 3;
sqlite3VdbeAddOp4Int(v, OP_Found, iParm+1, addr, r1, 0);
sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm+1, r1);
assert( pOrderBy==0 );
}
#endif /* SQLITE_OMIT_CTE */
sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
sqlite3ReleaseTempReg(pParse, r1);
break;
@@ -809,6 +787,51 @@ static void selectInnerLoop(
break;
}
#ifndef SQLITE_OMIT_CTE
/* Write the results into a priority queue that is order according to
** pDest->pOrderBy (in pSO). pDest->iSDParm (in iParm) is the cursor for an
** index with pSO->nExpr+2 columns. Build a key using pSO for the first
** pSO->nExpr columns, then make sure all keys are unique by adding a
** final OP_Sequence column. The last column is the record as a blob.
*/
case SRT_DistQueue:
case SRT_Queue: {
int nKey;
int r1, r2, r3;
int addrTest = 0;
ExprList *pSO;
pSO = pDest->pOrderBy;
assert( pSO );
nKey = pSO->nExpr;
r1 = sqlite3GetTempReg(pParse);
r2 = sqlite3GetTempRange(pParse, nKey+2);
r3 = r2+nKey+1;
sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r3);
if( eDest==SRT_DistQueue ){
/* If the destination is DistQueue, then cursor (iParm+1) is open
** on a second ephemeral index that holds all values every previously
** added to the queue. Only add this new value if it has never before
** been added */
addrTest = sqlite3VdbeAddOp4Int(v, OP_Found, iParm+1, 0, r3, 0);
sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm+1, r3);
}
for(i=0; i<nKey; i++){
sqlite3VdbeAddOp2(v, OP_SCopy,
regResult + pSO->a[i].u.x.iOrderByCol - 1,
r2+i);
}
sqlite3VdbeAddOp2(v, OP_Sequence, iParm, r2+nKey);
sqlite3VdbeAddOp3(v, OP_MakeRecord, r2, nKey+2, r1);
sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
if( addrTest ) sqlite3VdbeJumpHere(v, addrTest);
sqlite3ReleaseTempReg(pParse, r1);
sqlite3ReleaseTempRange(pParse, r2, nKey+2);
break;
}
#endif /* SQLITE_OMIT_CTE */
#if !defined(SQLITE_OMIT_TRIGGER)
/* Discard the results. This is used for SELECT statements inside
** the body of a TRIGGER. The purpose of such selects is to call
@@ -897,7 +920,7 @@ int sqlite3KeyInfoIsWriteable(KeyInfo *p){ return p->nRef==1; }
** function is responsible for seeing that this structure is eventually
** freed.
*/
static KeyInfo *keyInfoFromExprList(Parse *pParse, ExprList *pList){
static KeyInfo *keyInfoFromExprList(Parse *pParse, ExprList *pList, int nExtra){
int nExpr;
KeyInfo *pInfo;
struct ExprList_item *pItem;
@@ -905,7 +928,7 @@ static KeyInfo *keyInfoFromExprList(Parse *pParse, ExprList *pList){
int i;
nExpr = pList->nExpr;
pInfo = sqlite3KeyInfoAlloc(db, nExpr, 1);
pInfo = sqlite3KeyInfoAlloc(db, nExpr+nExtra, 1);
if( pInfo ){
assert( sqlite3KeyInfoIsWriteable(pInfo) );
for(i=0, pItem=pList->a; i<nExpr; i++, pItem++){
@@ -1713,9 +1736,9 @@ static CollSeq *multiSelectCollSeq(Parse *pParse, Select *p, int iCol){
**
** The setup-query runs once to generate an initial set of rows that go
** into a Queue table. Rows are extracted from the Queue table one by
** one. Each row extracted from iQueue is output to pDest. Then the single
** extracted row (now the iCurrent table) becomes the content of the
** recursive-table and recursive-query is run. The output of the recursive-query
** one. Each row extracted from Queue is output to pDest. Then the single
** extracted row (now in the iCurrent table) becomes the content of the
** recursive-table for a recursive-query run. The output of the recursive-query
** is added back into the Queue table. Then another row is extracted from Queue
** and the iteration continues until the Queue table is empty.
**
@@ -1754,18 +1777,17 @@ static void generateWithRecursiveQuery(
SelectDest destQueue; /* SelectDest targetting the Queue table */
int i; /* Loop counter */
int rc; /* Result code */
ExprList *pOrderBy; /* The ORDER BY clause */
/* Obtain authorization to do a recursive query */
if( sqlite3AuthCheck(pParse, SQLITE_RECURSIVE, 0, 0, 0) ) return;
addrBreak = sqlite3VdbeMakeLabel(v);
addrCont = sqlite3VdbeMakeLabel(v);
/* Check that there is no ORDER BY or LIMIT clause. Neither of these
** are currently supported on recursive queries.
*/
assert( p->pOffset==0 || p->pLimit );
if( p->pOrderBy || p->pLimit ){
if( /*p->pOrderBy ||*/ p->pLimit ){
sqlite3ErrorMsg(pParse, "%s in a recursive query",
p->pOrderBy ? "ORDER BY" : "LIMIT"
);
@@ -1780,22 +1802,34 @@ static void generateWithRecursiveQuery(
}
}
/* Allocate cursors for Queue and Distinct. The cursor number for
/* Detach the ORDER BY clause from the compound SELECT */
pOrderBy = p->pOrderBy;
p->pOrderBy = 0;
/* Allocate cursors numbers for Queue and Distinct. The cursor number for
** the Distinct table must be exactly one greater than Queue in order
** for the SRT_DistTable destination to work. */
** for the SRT_DistTable and SRT_DistQueue destinations to work. */
iQueue = pParse->nTab++;
if( p->op==TK_UNION ){
assert( SRT_Table+1==SRT_DistTable );
assert( SRT_Queue+1==SRT_DistQueue );
eDest++;
eDest = pOrderBy ? SRT_DistQueue : SRT_DistTable;
iDistinct = pParse->nTab++;
}else{
eDest = pOrderBy ? SRT_Queue : SRT_Table;
}
sqlite3SelectDestInit(&destQueue, eDest, iQueue);
/* Allocate cursors for Current, Queue, and Distinct. */
regCurrent = ++pParse->nMem;
sqlite3VdbeAddOp3(v, OP_OpenPseudo, iCurrent, regCurrent, nCol);
sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iQueue, nCol);
if( pOrderBy ){
KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pOrderBy, 1);
sqlite3VdbeAddOp4(v, OP_OpenEphemeral, iQueue, pOrderBy->nExpr+2, 0,
(char*)pKeyInfo, P4_KEYINFO);
destQueue.pOrderBy = pOrderBy;
}else{
sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iQueue, nCol);
}
VdbeComment((v, "Queue table"));
if( iDistinct ){
p->addrOpenEphm[0] = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iDistinct, 0);
p->selFlags |= SF_UsesEphemeral;
@@ -1803,19 +1837,26 @@ static void generateWithRecursiveQuery(
/* Store the results of the setup-query in Queue. */
rc = sqlite3Select(pParse, pSetup, &destQueue);
if( rc ) return;
if( rc ) goto end_of_recursive_query;
/* Find the next row in the Queue and output that row */
addrTop = sqlite3VdbeAddOp2(v, OP_Rewind, iQueue, addrBreak);
selectInnerLoop(pParse, p, p->pEList, iQueue,
0, 0, pDest, addrCont, addrBreak);
sqlite3VdbeResolveLabel(v, addrCont);
/* Transfer the next row in Queue over to Current */
sqlite3VdbeAddOp1(v, OP_NullRow, iCurrent); /* To reset column cache */
sqlite3VdbeAddOp2(v, OP_RowData, iQueue, regCurrent);
if( pOrderBy ){
sqlite3VdbeAddOp3(v, OP_Column, iQueue, pOrderBy->nExpr+1, regCurrent);
}else{
sqlite3VdbeAddOp2(v, OP_RowData, iQueue, regCurrent);
}
sqlite3VdbeAddOp1(v, OP_Delete, iQueue);
/* Output the single row in Current */
addrCont = sqlite3VdbeMakeLabel(v);
selectInnerLoop(pParse, p, p->pEList, iCurrent,
0, 0, pDest, addrCont, addrBreak);
sqlite3VdbeResolveLabel(v, addrCont);
/* Execute the recursive SELECT taking the single row in Current as
** the value for the recursive-table. Store the results in the Queue.
*/
@@ -1827,6 +1868,10 @@ static void generateWithRecursiveQuery(
/* Keep running the loop until the Queue is empty */
sqlite3VdbeAddOp2(v, OP_Goto, 0, addrTop);
sqlite3VdbeResolveLabel(v, addrBreak);
end_of_recursive_query:
p->pOrderBy = pOrderBy;
return;
}
#endif
@@ -4227,7 +4272,7 @@ static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){
"argument");
pFunc->iDistinct = -1;
}else{
KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pE->x.pList);
KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pE->x.pList, 0);
sqlite3VdbeAddOp4(v, OP_OpenEphemeral, pFunc->iDistinct, 0, 0,
(char*)pKeyInfo, P4_KEYINFO);
}
@@ -4636,7 +4681,7 @@ int sqlite3Select(
*/
if( pOrderBy ){
KeyInfo *pKeyInfo;
pKeyInfo = keyInfoFromExprList(pParse, pOrderBy);
pKeyInfo = keyInfoFromExprList(pParse, pOrderBy, 0);
pOrderBy->iECursor = pParse->nTab++;
p->addrOpenEphm[2] = addrSortIndex =
sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
@@ -4668,7 +4713,7 @@ int sqlite3Select(
sDistinct.tabTnct = pParse->nTab++;
sDistinct.addrTnct = sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
sDistinct.tabTnct, 0, 0,
(char*)keyInfoFromExprList(pParse, p->pEList),
(char*)keyInfoFromExprList(pParse, p->pEList, 0),
P4_KEYINFO);
sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
sDistinct.eTnctType = WHERE_DISTINCT_UNORDERED;
@@ -4792,7 +4837,7 @@ int sqlite3Select(
** will be converted into a Noop.
*/
sAggInfo.sortingIdx = pParse->nTab++;
pKeyInfo = keyInfoFromExprList(pParse, pGroupBy);
pKeyInfo = keyInfoFromExprList(pParse, pGroupBy, 0);
addrSortingIdx = sqlite3VdbeAddOp4(v, OP_SorterOpen,
sAggInfo.sortingIdx, sAggInfo.nSortingColumn,
0, (char*)pKeyInfo, P4_KEYINFO);