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Allow only a single recursive reference in a recursive CTE. Also require that this reference is not part of a sub-query.

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FossilOrigin-Name: a296b73360d34c9364eceb2cc09a9a92adc4abb8
This commit is contained in:
dan 2014-01-16 18:34:33 +00:00
parent 8290c2ad5a
commit eae73fbfb9
7 changed files with 62 additions and 85 deletions
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20
manifest
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@ -1,5 +1,5 @@
C Disable\sthe\sflattening\soptimization\sif\sthe\sparent\squery\sis\sthe\srecursive\spart\sof\sa\srecursive\sCTE\sand\sthe\ssub-query\sis\sa\scompound\squery.
D 2014-01-16T10:58:39.954
C Allow\sonly\sa\ssingle\srecursive\sreference\sin\sa\srecursive\sCTE.\sAlso\srequire\sthat\sthis\sreference\sis\snot\spart\sof\sa\ssub-query.
D 2014-01-16T18:34:33.041
F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
F Makefile.in 2ef13430cd359f7b361bb863504e227b25cc7f81
F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@ -175,7 +175,7 @@ F src/complete.c dc1d136c0feee03c2f7550bafc0d29075e36deac
F src/ctime.c 77779efbe78dd678d84bfb4fc2e87b6b6ad8dccd
F src/date.c 593c744b2623971e45affd0bde347631bdfa4625
F src/delete.c 91e1321021db5dc266360531b8b6550009d771ff
F src/expr.c c09e34fa7c58995009135b81f83cb62a676ad181
F src/expr.c e239763d8b43356fa1f46f1cf41d62a076f7f72e
F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
F src/fkey.c 2ab0f5384b70594468ef3ac5c7ed8ca24bfd17d5
F src/func.c 6325ac2ec10833ccf4d5c36d323709221d37ea19
@ -219,12 +219,12 @@ F src/printf.c 85d07756e45d7496d19439dcae3e6e9e0090f269
F src/random.c d10c1f85b6709ca97278428fd5db5bbb9c74eece
F src/resolve.c ae278d8ce037883323f677e78c241f64289f12ec
F src/rowset.c 64655f1a627c9c212d9ab497899e7424a34222e0
F src/select.c 29976d169853492a20d3201e8a83eeefa39a868f
F src/select.c 2d2da29fd4c877646109f7d2fba26b5cc454cd37
F src/shell.c 9f3bc02a658b8f61d2cbe60cfc482f660c1c6c48
F src/sqlite.h.in d94a8b89522f526ba711182ee161e06f8669bcc9
F src/sqlite3.rc 11094cc6a157a028b301a9f06b3d03089ea37c3e
F src/sqlite3ext.h 886f5a34de171002ad46fae8c36a7d8051c190fc
F src/sqliteInt.h 6db445ce172c249c29d8f532af64fd7051fe05dd
F src/sqliteInt.h b30bd95081be525b32551f180cf43ccfaff9f5bc
F src/sqliteLimit.h 164b0e6749d31e0daa1a4589a169d31c0dec7b3d
F src/status.c 7ac05a5c7017d0b9f0b4bcd701228b784f987158
F src/table.c 2cd62736f845d82200acfa1287e33feb3c15d62e
@ -280,7 +280,7 @@ F src/update.c c2706a6eb232a96345c35b7e1e75a188e26812bb
F src/utf.c 6fc6c88d50448c469c5c196acf21617a24f90269
F src/util.c e71f19b272f05c8695cf747b4bac1732685f9e5c
F src/vacuum.c 3728d74919d4fb1356f9e9a13e27773db60b7179
F src/vdbe.c b06d79951a3f0da9cb41cb0aae5fdf5612f718a9
F src/vdbe.c ccc8594e89751966022642464ec2b5c5fa7840a2
F src/vdbe.h e6c4c610fcabad4fa80ebb1efc6822a9367e2b26
F src/vdbeInt.h 42db251e9f863401ff847b90d5fe1614c89a6a56
F src/vdbeapi.c ce4e68ea4842cc6081046f533d088dcf01d247ad
@ -293,7 +293,7 @@ F src/vtab.c 21b932841e51ebd7d075e2d0ad1415dce8d2d5fd
F src/wal.c 7dc3966ef98b74422267e7e6e46e07ff6c6eb1b4
F src/wal.h df01efe09c5cb8c8e391ff1715cca294f89668a4
F src/walker.c e9e593d5bb798c3e67fc3893dfe7055c9e7d8d74
F src/where.c 27eb508c4184599a826e2ef3b4319cd28ba2c7af
F src/where.c 369b0259fabfb22644d197736ae622f762cbaba8
F src/whereInt.h 96a75c61f1d2b9d4a8e4bb17d89deb0cf7cba358
F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
F test/aggerror.test a867e273ef9e3d7919f03ef4f0e8c0d2767944f2
@ -1150,7 +1150,7 @@ F tool/vdbe-compress.tcl 0cf56e9263a152b84da86e75a5c0cdcdb7a47891
F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
F tool/warnings.sh d1a6de74685f360ab718efda6265994b99bbea01
F tool/win/sqlite.vsix 030f3eeaf2cb811a3692ab9c14d021a75ce41fff
P 7f953b568baa3eede0b9c144be0b9bc86496341a
R 1f82ce2970e79b42a60992cde0f0f626
P 6bfa387e82de47ca1f40225fe28d873e29d6f481
R d0f7d170eccd6b8c29b55960683e8b9a
U dan
Z da04231961fbad92750efdf2d0f0da36
Z 617b83d8e92edcc7afd63e19b605afe5

2
manifest.uuid
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@ -1 +1 @@
6bfa387e82de47ca1f40225fe28d873e29d6f481
a296b73360d34c9364eceb2cc09a9a92adc4abb8

1
src/expr.c
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@ -1065,7 +1065,6 @@ Select *sqlite3SelectDup(sqlite3 *db, Select *p, int flags){
pNew->addrOpenEphm[1] = -1;
pNew->addrOpenEphm[2] = -1;
pNew->pWith = withDup(db, p->pWith);
pNew->pRecurse = p->pRecurse;
return pNew;
}
#else

88
src/select.c
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@ -1744,7 +1744,7 @@ static int multiSelect(
** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
*/
assert( p && p->pPrior ); /* Calling function guarantees this much */
assert( p->pRecurse==0 || p->op==TK_ALL || p->op==TK_UNION );
assert( (p->selFlags & SF_Recursive)==0 || p->op==TK_ALL || p->op==TK_UNION );
db = pParse->db;
pPrior = p->pPrior;
assert( pPrior->pRightmost!=pPrior );
@ -1794,27 +1794,36 @@ static int multiSelect(
/* If this is a recursive query, check that there is no ORDER BY or
** LIMIT clause. Neither of these are supported. */
assert( p->pOffset==0 || p->pLimit );
if( p->pRecurse && (p->pOrderBy || p->pLimit) ){
if( (p->selFlags & SF_Recursive) && (p->pOrderBy || p->pLimit) ){
sqlite3ErrorMsg(pParse, "%s in a recursive query is not allowed",
p->pOrderBy ? "ORDER BY" : "LIMIT"
);
goto multi_select_end;
}
if( p->pRecurse ){
if( p->selFlags & SF_Recursive ){
SrcList *pSrc = p->pSrc;
int nCol = p->pEList->nExpr;
int addrNext;
int addrSwap;
int iCont, iBreak;
int tmp1, tmp2; /* Cursors used to access temporary tables */
int tmp1; /* Intermediate table */
int tmp2; /* Next intermediate table */
int tmp3 = 0; /* To ensure unique results if UNION */
int eDest = SRT_Table;
SelectDest tmp2dest;
int i;
iBreak = sqlite3VdbeMakeLabel(v);
iCont = sqlite3VdbeMakeLabel(v);
tmp1 = pParse->nTab++;
for(i=0; ALWAYS(i<pSrc->nSrc); i++){
if( pSrc->a[i].isRecursive ){
tmp1 = pSrc->a[i].iCursor;
break;
}
}
tmp2 = pParse->nTab++;
if( p->op==TK_UNION ){
eDest = SRT_DistTable;
@ -1848,11 +1857,7 @@ static int multiSelect(
** SELECT is running, the contents of tmp1 are read by recursive
** references to the current CTE. */
p->pPrior = 0;
p->pRecurse->tnum = tmp1;
assert( (p->pRecurse->tabFlags & TF_Recursive)==0 );
p->pRecurse->tabFlags |= TF_Recursive;
rc = sqlite3Select(pParse, p, &tmp2dest);
p->pRecurse->tabFlags &= ~TF_Recursive;
assert( p->pPrior==0 );
p->pPrior = pPrior;
if( rc ) goto multi_select_end;
@ -3009,8 +3014,8 @@ static int flattenSubquery(
if( pSub->pLimit && (p->selFlags & SF_Distinct)!=0 ){
return 0; /* Restriction (21) */
}
if( pSub->pRecurse ) return 0; /* Restriction (22) */
if( p->pRecurse && pSub->pPrior ) return 0; /* Restriction (23) */
if( pSub->selFlags & SF_Recursive ) return 0; /* Restriction (22) */
if( (p->selFlags & SF_Recursive) && pSub->pPrior ) return 0; /* (23) */
/* OBSOLETE COMMENT 1:
** Restriction 3: If the subquery is a join, make sure the subquery is
@ -3593,19 +3598,10 @@ static int withExpand(
assert( pFrom->pTab==0 );
pCte = searchWith(pParse->pWith, pFrom);
if( pCte==0 ){
/* no-op */
}else if( pCte==pParse->pCte && (pTab = pCte->pTab) ){
/* This is the recursive part of a recursive CTE */
assert( pFrom->pTab==0 && pFrom->isRecursive==0 && pFrom->pSelect==0 );
pFrom->pTab = pTab;
pFrom->isRecursive = 1;
pTab->nRef++;
}else{
if( pCte ){
ExprList *pEList;
Select *pSel;
Select *pLeft; /* Left-most SELECT statement */
int bRecursive;
pFrom->pTab = pTab = sqlite3DbMallocZero(db, sizeof(Table));
if( pTab==0 ) return WRC_Abort;
@ -3618,16 +3614,37 @@ static int withExpand(
if( db->mallocFailed ) return SQLITE_NOMEM;
assert( pFrom->pSelect );
if( ctePush(pParse, pCte) ) return WRC_Abort;
/* Check if this is a recursive CTE. */
pSel = pFrom->pSelect;
bRecursive = (pSel->op==TK_ALL || pSel->op==TK_UNION);
if( bRecursive ){
assert( pSel->pPrior );
sqlite3WalkSelect(pWalker, pSel->pPrior);
}else{
sqlite3WalkSelect(pWalker, pSel);
if( pSel->op==TK_ALL || pSel->op==TK_UNION ){
int i;
SrcList *pSrc = pFrom->pSelect->pSrc;
for(i=0; i<pSrc->nSrc; i++){
struct SrcList_item *pItem = &pSrc->a[i];
if( pItem->zDatabase==0
&& pItem->zName!=0
&& 0==sqlite3StrICmp(pItem->zName, pCte->zName)
){
pItem->pTab = pTab;
pItem->isRecursive = 1;
pTab->nRef++;
pSel->selFlags |= SF_Recursive;
}
}
}
/* Only one recursive reference is permitted. */
if( pTab->nRef>2 ){
sqlite3ErrorMsg(
pParse, "multiple recursive references in cte: %s", pCte->zName
);
return WRC_Abort;
}
assert( pTab->nRef==1 || ((pSel->selFlags&SF_Recursive) && pTab->nRef==2 ));
if( ctePush(pParse, pCte) ) return WRC_Abort;
sqlite3WalkSelect(pWalker, pTab->nRef==2 ? pSel->pPrior : pSel);
for(pLeft=pSel; pLeft->pPrior; pLeft=pLeft->pPrior);
pEList = pLeft->pEList;
if( pCte->pCols ){
@ -3639,20 +3656,9 @@ static int withExpand(
}
pEList = pCte->pCols;
}
selectColumnsFromExprList(pParse, pEList, &pTab->nCol, &pTab->aCol);
if( bRecursive ){
int nRef = pTab->nRef;
pCte->pTab = pTab;
sqlite3WalkSelect(pWalker, pSel);
pCte->pTab = 0;
if( pTab->nRef > nRef){
pSel->pRecurse = pTab;
assert( pTab->tnum==0 );
}
}
if( pSel->selFlags & SF_Recursive ) sqlite3WalkSelect(pWalker, pSel);
ctePop(pParse, pCte);
}
@ -3715,6 +3721,8 @@ static int selectExpander(Walker *pWalker, Select *p){
*/
for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
Table *pTab;
assert( pFrom->isRecursive==0 || pFrom->pTab );
if( pFrom->isRecursive ) continue;
if( pFrom->pTab!=0 ){
/* This statement has already been prepared. There is no need
** to go further. */

5
src/sqliteInt.h
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@ -2131,7 +2131,6 @@ struct NameContext {
*/
struct Select {
ExprList *pEList; /* The fields of the result */
Table *pRecurse; /* Non-NULL for the recursive part of recursive CTE */
u8 op; /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
u16 selFlags; /* Various SF_* values */
int iLimit, iOffset; /* Memory registers holding LIMIT & OFFSET counters */
@ -2165,6 +2164,7 @@ struct Select {
#define SF_Materialize 0x0100 /* Force materialization of views */
#define SF_NestedFrom 0x0200 /* Part of a parenthesized FROM clause */
#define SF_MaybeConvert 0x0400 /* Need convertCompoundSelectToSubquery() */
#define SF_Recursive 0x0800 /* The recursive part of a recursive CTE */
/*
@ -2640,7 +2640,7 @@ int sqlite3WalkSelectFrom(Walker*, Select*);
#define WRC_Abort 2 /* Abandon the tree walk */
/*
** An instance of this structure represents a set of on or more CTEs
** An instance of this structure represents a set of one or more CTEs
** (common table expressions) created by a single WITH clause.
*/
struct With {
@ -2651,7 +2651,6 @@ struct With {
ExprList *pCols; /* List of explicit column names, or NULL */
Select *pSelect; /* The definition of this CTE */
struct Cte *pOuterCte; /* Next WITH clause in outer context */
Table *pTab; /* Table object for this CTE */
} a[1];
};

23
src/vdbe.c
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@ -3370,29 +3370,6 @@ case OP_OpenEphemeral: {
}
#ifndef SQLITE_OMIT_CTE
/* Opcode: OpenEphreader P1 P2 * * *
**
** P2 is a cursor opened by the OpenEphemeral opcode. This opcode opens
** a new read-only cursor named P1 that accesses the same epheremal table
** as P2.
*/
case OP_OpenEphreader: {
VdbeCursor *pEph;
VdbeCursor *pCx;
Pgno pgno;
pEph = p->apCsr[pOp->p2];
pCx = allocateCursor(p, pOp->p1, pEph->nField, -1, 1);
if( pCx==0 ) goto no_mem;
pCx->nullRow = 1;
pCx->pKeyInfo = pEph->pKeyInfo;
pCx->isTable = pEph->isTable;
pCx->isOrdered = pEph->isOrdered;
pgno = MASTER_ROOT + !pCx->isTable;
rc = sqlite3BtreeCursor(pEph->pBt, pgno, 0, pCx->pKeyInfo, pCx->pCursor);
break;
}
/* Opcode: SwapCursors P1 P2 * * *
**
** Parameters P1 and P2 are both cursors opened by the OpenEphemeral

8
src/where.c
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@ -5654,13 +5654,7 @@ WhereInfo *sqlite3WhereBegin(
iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
pLoop = pLevel->pWLoop;
if( (pTab->tabFlags & TF_Ephemeral)!=0 || pTab->pSelect ){
#ifndef SQLITE_OMIT_CTE
if( pTab->tabFlags & TF_Recursive ){
int iCur = pTabItem->iCursor;
sqlite3VdbeAddOp2(v, OP_OpenEphreader, iCur, pTab->tnum);
}
#endif
/* Otherwise do nothing */
/* Do nothing */
}else
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){