DBD-SQLite-Amalgamation
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sqlite-amalgamation.c view on Meta::CPAN
** C: yield X
** if EOF goto D
** insert the select result into <table> from R..R+n
** goto C
** D: cleanup
**
** The 4th template is used if the insert statement takes its
** values from a SELECT but the data is being inserted into a table
** that is also read as part of the SELECT. In the third form,
** we have to use a intermediate table to store the results of
** the select. The template is like this:
**
** EOF <- 0
** X <- A
** goto B
** A: setup for the SELECT
** loop over the tables in the SELECT
** load value into register R..R+n
** yield X
** end loop
** cleanup after the SELECT
** EOF <- 1
** yield X
** halt-error
** B: open temp table
** L: yield X
** if EOF goto M
** insert row from R..R+n into temp table
** goto L
** M: open write cursor to <table> and its indices
** rewind temp table
** C: loop over rows of intermediate table
** transfer values form intermediate table into <table>
** end loop
** D: cleanup
*/
SQLITE_PRIVATE void sqlite3Insert(
Parse *pParse, /* Parser context */
SrcList *pTabList, /* Name of table into which we are inserting */
ExprList *pList, /* List of values to be inserted */
Select *pSelect, /* A SELECT statement to use as the data source */
IdList *pColumn, /* Column names corresponding to IDLIST. */
int onError /* How to handle constraint errors */
){
sqlite3 *db; /* The main database structure */
Table *pTab; /* The table to insert into. aka TABLE */
char *zTab; /* Name of the table into which we are inserting */
const char *zDb; /* Name of the database holding this table */
int i, j, idx; /* Loop counters */
Vdbe *v; /* Generate code into this virtual machine */
Index *pIdx; /* For looping over indices of the table */
int nColumn; /* Number of columns in the data */
int nHidden = 0; /* Number of hidden columns if TABLE is virtual */
int baseCur = 0; /* VDBE Cursor number for pTab */
int keyColumn = -1; /* Column that is the INTEGER PRIMARY KEY */
int endOfLoop; /* Label for the end of the insertion loop */
int useTempTable = 0; /* Store SELECT results in intermediate table */
int srcTab = 0; /* Data comes from this temporary cursor if >=0 */
int addrInsTop = 0; /* Jump to label "D" */
int addrCont = 0; /* Top of insert loop. Label "C" in templates 3 and 4 */
int addrSelect = 0; /* Address of coroutine that implements the SELECT */
SelectDest dest; /* Destination for SELECT on rhs of INSERT */
int newIdx = -1; /* Cursor for the NEW pseudo-table */
int iDb; /* Index of database holding TABLE */
Db *pDb; /* The database containing table being inserted into */
int appendFlag = 0; /* True if the insert is likely to be an append */
/* Register allocations */
int regFromSelect; /* Base register for data coming from SELECT */
int regAutoinc = 0; /* Register holding the AUTOINCREMENT counter */
int regRowCount = 0; /* Memory cell used for the row counter */
int regIns; /* Block of regs holding rowid+data being inserted */
int regRowid; /* registers holding insert rowid */
int regData; /* register holding first column to insert */
int regRecord; /* Holds the assemblied row record */
int regEof; /* Register recording end of SELECT data */
int *aRegIdx = 0; /* One register allocated to each index */
#ifndef SQLITE_OMIT_TRIGGER
int isView; /* True if attempting to insert into a view */
int triggers_exist = 0; /* True if there are FOR EACH ROW triggers */
#endif
db = pParse->db;
if( pParse->nErr || db->mallocFailed ){
goto insert_cleanup;
}
/* Locate the table into which we will be inserting new information.
*/
assert( pTabList->nSrc==1 );
zTab = pTabList->a[0].zName;
if( zTab==0 ) goto insert_cleanup;
pTab = sqlite3SrcListLookup(pParse, pTabList);
if( pTab==0 ){
goto insert_cleanup;
}
iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
assert( iDb<db->nDb );
pDb = &db->aDb[iDb];
zDb = pDb->zName;
if( sqlite3AuthCheck(pParse, SQLITE_INSERT, pTab->zName, 0, zDb) ){
goto insert_cleanup;
}
/* Figure out if we have any triggers and if the table being
** inserted into is a view
*/
#ifndef SQLITE_OMIT_TRIGGER
triggers_exist = sqlite3TriggersExist(pParse, pTab, TK_INSERT, 0);
isView = pTab->pSelect!=0;
#else
# define triggers_exist 0
# define isView 0
#endif
#ifdef SQLITE_OMIT_VIEW
# undef isView
# define isView 0
#endif
sqlite-amalgamation.c view on Meta::CPAN
#ifndef SQLITE_OMIT_XFER_OPT
/* If the statement is of the form
**
** INSERT INTO <table1> SELECT * FROM <table2>;
**
** Then special optimizations can be applied that make the transfer
** very fast and which reduce fragmentation of indices.
**
** This is the 2nd template.
*/
if( pColumn==0 && xferOptimization(pParse, pTab, pSelect, onError, iDb) ){
assert( !triggers_exist );
assert( pList==0 );
goto insert_cleanup;
}
#endif /* SQLITE_OMIT_XFER_OPT */
/* If this is an AUTOINCREMENT table, look up the sequence number in the
** sqlite_sequence table and store it in memory cell regAutoinc.
*/
regAutoinc = autoIncBegin(pParse, iDb, pTab);
/* Figure out how many columns of data are supplied. If the data
** is coming from a SELECT statement, then generate a co-routine that
** produces a single row of the SELECT on each invocation. The
** co-routine is the common header to the 3rd and 4th templates.
*/
if( pSelect ){
/* Data is coming from a SELECT. Generate code to implement that SELECT
** as a co-routine. The code is common to both the 3rd and 4th
** templates:
**
** EOF <- 0
** X <- A
** goto B
** A: setup for the SELECT
** loop over the tables in the SELECT
** load value into register R..R+n
** yield X
** end loop
** cleanup after the SELECT
** EOF <- 1
** yield X
** halt-error
**
** On each invocation of the co-routine, it puts a single row of the
** SELECT result into registers dest.iMem...dest.iMem+dest.nMem-1.
** (These output registers are allocated by sqlite3Select().) When
** the SELECT completes, it sets the EOF flag stored in regEof.
*/
int rc, j1;
regEof = ++pParse->nMem;
sqlite3VdbeAddOp2(v, OP_Integer, 0, regEof); /* EOF <- 0 */
VdbeComment((v, "SELECT eof flag"));
sqlite3SelectDestInit(&dest, SRT_Coroutine, ++pParse->nMem);
addrSelect = sqlite3VdbeCurrentAddr(v)+2;
sqlite3VdbeAddOp2(v, OP_Integer, addrSelect-1, dest.iParm);
j1 = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
VdbeComment((v, "Jump over SELECT coroutine"));
/* Resolve the expressions in the SELECT statement and execute it. */
rc = sqlite3Select(pParse, pSelect, &dest, 0, 0, 0);
if( rc || pParse->nErr || db->mallocFailed ){
goto insert_cleanup;
}
sqlite3VdbeAddOp2(v, OP_Integer, 1, regEof); /* EOF <- 1 */
sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm); /* yield X */
sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_INTERNAL, OE_Abort);
VdbeComment((v, "End of SELECT coroutine"));
sqlite3VdbeJumpHere(v, j1); /* label B: */
regFromSelect = dest.iMem;
assert( pSelect->pEList );
nColumn = pSelect->pEList->nExpr;
assert( dest.nMem==nColumn );
/* Set useTempTable to TRUE if the result of the SELECT statement
** should be written into a temporary table (template 4). Set to
** FALSE if each* row of the SELECT can be written directly into
** the destination table (template 3).
**
** A temp table must be used if the table being updated is also one
** of the tables being read by the SELECT statement. Also use a
** temp table in the case of row triggers.
*/
if( triggers_exist || readsTable(v, addrSelect, iDb, pTab) ){
useTempTable = 1;
}
if( useTempTable ){
/* Invoke the coroutine to extract information from the SELECT
** and add it to a transient table srcTab. The code generated
** here is from the 4th template:
**
** B: open temp table
** L: yield X
** if EOF goto M
** insert row from R..R+n into temp table
** goto L
** M: ...
*/
int regRec; /* Register to hold packed record */
int regRowid; /* Register to hold temp table ROWID */
int addrTop; /* Label "L" */
int addrIf; /* Address of jump to M */
srcTab = pParse->nTab++;
regRec = sqlite3GetTempReg(pParse);
regRowid = sqlite3GetTempReg(pParse);
sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
addrTop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);
addrIf = sqlite3VdbeAddOp1(v, OP_If, regEof);
sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regRowid);
sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regRowid);
sqlite3VdbeAddOp2(v, OP_Goto, 0, addrTop);
sqlite3VdbeJumpHere(v, addrIf);
sqlite3ReleaseTempReg(pParse, regRec);
sqlite3ReleaseTempReg(pParse, regRowid);
}
}else{
/* This is the case if the data for the INSERT is coming from a VALUES
** clause
*/
NameContext sNC;
memset(&sNC, 0, sizeof(sNC));
sNC.pParse = pParse;
srcTab = -1;
assert( useTempTable==0 );
nColumn = pList ? pList->nExpr : 0;
for(i=0; i<nColumn; i++){
if( sqlite3ExprResolveNames(&sNC, pList->a[i].pExpr) ){
goto insert_cleanup;
}
}
}
/* Make sure the number of columns in the source data matches the number
** of columns to be inserted into the table.
*/
if( IsVirtual(pTab) ){
for(i=0; i<pTab->nCol; i++){
nHidden += (IsHiddenColumn(&pTab->aCol[i]) ? 1 : 0);
}
}
if( pColumn==0 && nColumn && nColumn!=(pTab->nCol-nHidden) ){
sqlite3ErrorMsg(pParse,
"table %S has %d columns but %d values were supplied",
pTabList, 0, pTab->nCol, nColumn);
goto insert_cleanup;
}
sqlite-amalgamation.c view on Meta::CPAN
** temporary tables needed to implement the compound select.
** Attach the KeyInfo structure to all temporary tables.
**
** This section is run by the right-most SELECT statement only.
** SELECT statements to the left always skip this part. The right-most
** SELECT might also skip this part if it has no ORDER BY clause and
** no temp tables are required.
*/
if( p->usesEphm ){
int i; /* Loop counter */
KeyInfo *pKeyInfo; /* Collating sequence for the result set */
Select *pLoop; /* For looping through SELECT statements */
CollSeq **apColl; /* For looping through pKeyInfo->aColl[] */
int nCol; /* Number of columns in result set */
assert( p->pRightmost==p );
nCol = p->pEList->nExpr;
pKeyInfo = sqlite3DbMallocZero(db,
sizeof(*pKeyInfo)+nCol*(sizeof(CollSeq*) + 1));
if( !pKeyInfo ){
rc = SQLITE_NOMEM;
goto multi_select_end;
}
pKeyInfo->enc = ENC(db);
pKeyInfo->nField = nCol;
for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){
*apColl = multiSelectCollSeq(pParse, p, i);
if( 0==*apColl ){
*apColl = db->pDfltColl;
}
}
for(pLoop=p; pLoop; pLoop=pLoop->pPrior){
for(i=0; i<2; i++){
int addr = pLoop->addrOpenEphm[i];
if( addr<0 ){
/* If [0] is unused then [1] is also unused. So we can
** always safely abort as soon as the first unused slot is found */
assert( pLoop->addrOpenEphm[1]<0 );
break;
}
sqlite3VdbeChangeP2(v, addr, nCol);
sqlite3VdbeChangeP4(v, addr, (char*)pKeyInfo, P4_KEYINFO);
pLoop->addrOpenEphm[i] = -1;
}
}
sqlite3DbFree(db, pKeyInfo);
}
multi_select_end:
pDest->iMem = dest.iMem;
pDest->nMem = dest.nMem;
sqlite3SelectDelete(db, pDelete);
return rc;
}
#endif /* SQLITE_OMIT_COMPOUND_SELECT */
/*
** Code an output subroutine for a coroutine implementation of a
** SELECT statment.
**
** The data to be output is contained in pIn->iMem. There are
** pIn->nMem columns to be output. pDest is where the output should
** be sent.
**
** regReturn is the number of the register holding the subroutine
** return address.
**
** If regPrev>0 then it is a the first register in a vector that
** records the previous output. mem[regPrev] is a flag that is false
** if there has been no previous output. If regPrev>0 then code is
** generated to suppress duplicates. pKeyInfo is used for comparing
** keys.
**
** If the LIMIT found in p->iLimit is reached, jump immediately to
** iBreak.
*/
static int generateOutputSubroutine(
Parse *pParse, /* Parsing context */
Select *p, /* The SELECT statement */
SelectDest *pIn, /* Coroutine supplying data */
SelectDest *pDest, /* Where to send the data */
int regReturn, /* The return address register */
int regPrev, /* Previous result register. No uniqueness if 0 */
KeyInfo *pKeyInfo, /* For comparing with previous entry */
int p4type, /* The p4 type for pKeyInfo */
int iBreak /* Jump here if we hit the LIMIT */
){
Vdbe *v = pParse->pVdbe;
int iContinue;
int addr;
addr = sqlite3VdbeCurrentAddr(v);
iContinue = sqlite3VdbeMakeLabel(v);
/* Suppress duplicates for UNION, EXCEPT, and INTERSECT
*/
if( regPrev ){
int j1, j2;
j1 = sqlite3VdbeAddOp1(v, OP_IfNot, regPrev);
j2 = sqlite3VdbeAddOp4(v, OP_Compare, pIn->iMem, regPrev+1, pIn->nMem,
(char*)pKeyInfo, p4type);
sqlite3VdbeAddOp3(v, OP_Jump, j2+2, iContinue, j2+2);
sqlite3VdbeJumpHere(v, j1);
sqlite3ExprCodeCopy(pParse, pIn->iMem, regPrev+1, pIn->nMem);
sqlite3VdbeAddOp2(v, OP_Integer, 1, regPrev);
}
if( pParse->db->mallocFailed ) return 0;
/* Suppress the the first OFFSET entries if there is an OFFSET clause
*/
codeOffset(v, p, iContinue);
switch( pDest->eDest ){
/* Store the result as data using a unique key.
*/
case SRT_Table:
case SRT_EphemTab: {
int r1 = sqlite3GetTempReg(pParse);
sqlite-amalgamation.c view on Meta::CPAN
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
/* Send the data to the callback function or to a subroutine. In the
** case of a subroutine, the subroutine itself is responsible for
** popping the data from the stack.
*/
case SRT_Coroutine: {
if( pDest->iMem==0 ){
pDest->iMem = sqlite3GetTempRange(pParse, pIn->nMem);
pDest->nMem = pIn->nMem;
}
sqlite3ExprCodeMove(pParse, pIn->iMem, pDest->iMem, pDest->nMem);
sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
break;
}
case SRT_Callback: {
sqlite3VdbeAddOp2(v, OP_ResultRow, pIn->iMem, pIn->nMem);
sqlite3ExprCacheAffinityChange(pParse, pIn->iMem, pIn->nMem);
break;
}
#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
** user-defined functions that have side effects. We do not care
** about the actual results of the select.
*/
default: {
break;
}
#endif
}
/* Jump to the end of the loop if the LIMIT is reached.
*/
if( p->iLimit ){
sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
sqlite3VdbeAddOp2(v, OP_IfZero, p->iLimit, iBreak);
}
/* Generate the subroutine return
*/
sqlite3VdbeResolveLabel(v, iContinue);
sqlite3VdbeAddOp1(v, OP_Return, regReturn);
return addr;
}
/*
** Alternative compound select code generator for cases when there
** is an ORDER BY clause.
**
** We assume a query of the following form:
**
** <selectA> <operator> <selectB> ORDER BY <orderbylist>
**
** <operator> is one of UNION ALL, UNION, EXCEPT, or INTERSECT. The idea
** is to code both <selectA> and <selectB> with the ORDER BY clause as
** co-routines. Then run the co-routines in parallel and merge the results
** into the output. In addition to the two coroutines (called selectA and
** selectB) there are 7 subroutines:
**
** outA: Move the output of the selectA coroutine into the output
** of the compound query.
**
** outB: Move the output of the selectB coroutine into the output
** of the compound query. (Only generated for UNION and
** UNION ALL. EXCEPT and INSERTSECT never output a row that
** appears only in B.)
**
** AltB: Called when there is data from both coroutines and A<B.
**
** AeqB: Called when there is data from both coroutines and A==B.
**
** AgtB: Called when there is data from both coroutines and A>B.
**
** EofA: Called when data is exhausted from selectA.
**
** EofB: Called when data is exhausted from selectB.
**
** The implementation of the latter five subroutines depend on which
** <operator> is used:
**
**
** UNION ALL UNION EXCEPT INTERSECT
** ------------- ----------------- -------------- -----------------
** AltB: outA, nextA outA, nextA outA, nextA nextA
**
** AeqB: outA, nextA nextA nextA outA, nextA
**
** AgtB: outB, nextB outB, nextB nextB nextB
**
** EofA: outB, nextB outB, nextB halt halt
**
** EofB: outA, nextA outA, nextA outA, nextA halt
**
** In the AltB, AeqB, and AgtB subroutines, an EOF on A following nextA
** causes an immediate jump to EofA and an EOF on B following nextB causes
** an immediate jump to EofB. Within EofA and EofB, and EOF on entry or
** following nextX causes a jump to the end of the select processing.
**
** Duplicate removal in the UNION, EXCEPT, and INTERSECT cases is handled
** within the output subroutine. The regPrev register set holds the previously
** output value. A comparison is made against this value and the output
** is skipped if the next results would be the same as the previous.
**
** The implementation plan is to implement the two coroutines and seven
** subroutines first, then put the control logic at the bottom. Like this:
**
** goto Init
** coA: coroutine for left query (A)
** coB: coroutine for right query (B)
** outA: output one row of A
** outB: output one row of B (UNION and UNION ALL only)
** EofA: ...
** EofB: ...
** AltB: ...
** AeqB: ...
** AgtB: ...
** Init: initialize coroutine registers
** yield coA
** if eof(A) goto EofA
** yield coB
** if eof(B) goto EofB
** Cmpr: Compare A, B
** Jump AltB, AeqB, AgtB
** End: ...
**
** We call AltB, AeqB, AgtB, EofA, and EofB "subroutines" but they are not
** actually called using Gosub and they do not Return. EofA and EofB loop
** until all data is exhausted then jump to the "end" labe. AltB, AeqB,
** and AgtB jump to either L2 or to one of EofA or EofB.
*/
#ifndef SQLITE_OMIT_COMPOUND_SELECT
static int multiSelectOrderBy(
Parse *pParse, /* Parsing context */
Select *p, /* The right-most of SELECTs to be coded */
SelectDest *pDest /* What to do with query results */
){
int i, j; /* Loop counters */
Select *pPrior; /* Another SELECT immediately to our left */
Vdbe *v; /* Generate code to this VDBE */
SelectDest destA; /* Destination for coroutine A */
SelectDest destB; /* Destination for coroutine B */
int regAddrA; /* Address register for select-A coroutine */
int regEofA; /* Flag to indicate when select-A is complete */
int regAddrB; /* Address register for select-B coroutine */
int regEofB; /* Flag to indicate when select-B is complete */
int addrSelectA; /* Address of the select-A coroutine */
int addrSelectB; /* Address of the select-B coroutine */
int regOutA; /* Address register for the output-A subroutine */
int regOutB; /* Address register for the output-B subroutine */
int addrOutA; /* Address of the output-A subroutine */
int addrOutB; /* Address of the output-B subroutine */
int addrEofA; /* Address of the select-A-exhausted subroutine */
int addrEofB; /* Address of the select-B-exhausted subroutine */
int addrAltB; /* Address of the A<B subroutine */
int addrAeqB; /* Address of the A==B subroutine */
int addrAgtB; /* Address of the A>B subroutine */
int regLimitA; /* Limit register for select-A */
int regLimitB; /* Limit register for select-A */
int regPrev; /* A range of registers to hold previous output */
int savedLimit; /* Saved value of p->iLimit */
int savedOffset; /* Saved value of p->iOffset */
int labelCmpr; /* Label for the start of the merge algorithm */
int labelEnd; /* Label for the end of the overall SELECT stmt */
int j1; /* Jump instructions that get retargetted */
int op; /* One of TK_ALL, TK_UNION, TK_EXCEPT, TK_INTERSECT */
KeyInfo *pKeyDup; /* Comparison information for duplicate removal */
KeyInfo *pKeyMerge; /* Comparison information for merging rows */
sqlite3 *db; /* Database connection */
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 */
u8 NotUsed; /* Dummy variables */
assert( p->pOrderBy!=0 );
db = pParse->db;
v = pParse->pVdbe;
if( v==0 ) return SQLITE_NOMEM;
labelEnd = sqlite3VdbeMakeLabel(v);
labelCmpr = sqlite3VdbeMakeLabel(v);
/* Patch up the ORDER BY clause
*/
op = p->op;
pPrior = p->pPrior;
assert( pPrior->pOrderBy==0 );
pOrderBy = p->pOrderBy;
assert( pOrderBy );
if( processCompoundOrderBy(pParse, p) ){
return SQLITE_ERROR;
}
nOrderBy = pOrderBy->nExpr;
/* For operators other than UNION ALL we have to make sure that
** the ORDER BY clause covers every term of the result set. Add
** terms to the ORDER BY clause as necessary.
*/
if( op!=TK_ALL ){
for(i=1; db->mallocFailed==0 && i<=p->pEList->nExpr; i++){
for(j=0; j<nOrderBy; j++){
Expr *pTerm = pOrderBy->a[j].pExpr;
assert( pTerm->op==TK_INTEGER );
assert( (pTerm->flags & EP_IntValue)!=0 );
if( pTerm->iTable==i ) break;
}
if( j==nOrderBy ){
Expr *pNew = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, 0);
sqlite-amalgamation.c view on Meta::CPAN
pPrior->pOrderBy = sqlite3ExprListDup(pParse->db, pOrderBy);
/* Allocate a range of temporary registers and the KeyInfo needed
** for the logic that removes duplicate result rows when the
** operator is UNION, EXCEPT, or INTERSECT (but not UNION ALL).
*/
if( op==TK_ALL ){
regPrev = 0;
}else{
int nExpr = p->pEList->nExpr;
assert( nOrderBy>=nExpr );
regPrev = sqlite3GetTempRange(pParse, nExpr+1);
sqlite3VdbeAddOp2(v, OP_Integer, 0, regPrev);
pKeyDup = sqlite3DbMallocZero(db,
sizeof(*pKeyDup) + nExpr*(sizeof(CollSeq*)+1) );
if( pKeyDup ){
pKeyDup->aSortOrder = (u8*)&pKeyDup->aColl[nExpr];
pKeyDup->nField = nExpr;
pKeyDup->enc = ENC(db);
for(i=0; i<nExpr; i++){
pKeyDup->aColl[i] = multiSelectCollSeq(pParse, p, i);
pKeyDup->aSortOrder[i] = 0;
}
}
}
/* Separate the left and the right query from one another
*/
p->pPrior = 0;
pPrior->pRightmost = 0;
processOrderGroupBy(pParse, p, p->pOrderBy, 1, &NotUsed);
if( pPrior->pPrior==0 ){
processOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, 1, &NotUsed);
}
/* Compute the limit registers */
computeLimitRegisters(pParse, p, labelEnd);
if( p->iLimit && op==TK_ALL ){
regLimitA = ++pParse->nMem;
regLimitB = ++pParse->nMem;
sqlite3VdbeAddOp2(v, OP_Copy, p->iOffset ? p->iOffset+1 : p->iLimit,
regLimitA);
sqlite3VdbeAddOp2(v, OP_Copy, regLimitA, regLimitB);
}else{
regLimitA = regLimitB = 0;
}
sqlite3ExprDelete(db, p->pLimit);
p->pLimit = 0;
sqlite3ExprDelete(db, p->pOffset);
p->pOffset = 0;
regAddrA = ++pParse->nMem;
regEofA = ++pParse->nMem;
regAddrB = ++pParse->nMem;
regEofB = ++pParse->nMem;
regOutA = ++pParse->nMem;
regOutB = ++pParse->nMem;
sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB);
/* Jump past the various subroutines and coroutines to the main
** merge loop
*/
j1 = sqlite3VdbeAddOp0(v, OP_Goto);
addrSelectA = sqlite3VdbeCurrentAddr(v);
/* Generate a coroutine to evaluate the SELECT statement to the
** left of the compound operator - the "A" select.
*/
VdbeNoopComment((v, "Begin coroutine for left SELECT"));
pPrior->iLimit = regLimitA;
sqlite3Select(pParse, pPrior, &destA, 0, 0, 0);
sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofA);
sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
VdbeNoopComment((v, "End coroutine for left SELECT"));
/* Generate a coroutine to evaluate the SELECT statement on
** the right - the "B" select
*/
addrSelectB = sqlite3VdbeCurrentAddr(v);
VdbeNoopComment((v, "Begin coroutine for right SELECT"));
savedLimit = p->iLimit;
savedOffset = p->iOffset;
p->iLimit = regLimitB;
p->iOffset = 0;
sqlite3Select(pParse, p, &destB, 0, 0, 0);
p->iLimit = savedLimit;
p->iOffset = savedOffset;
sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofB);
sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
VdbeNoopComment((v, "End coroutine for right SELECT"));
/* Generate a subroutine that outputs the current row of the A
** select as the next output row of the compound select.
*/
VdbeNoopComment((v, "Output routine for A"));
addrOutA = generateOutputSubroutine(pParse,
p, &destA, pDest, regOutA,
regPrev, pKeyDup, P4_KEYINFO_HANDOFF, labelEnd);
/* Generate a subroutine that outputs the current row of the B
** select as the next output row of the compound select.
*/
if( op==TK_ALL || op==TK_UNION ){
VdbeNoopComment((v, "Output routine for B"));
addrOutB = generateOutputSubroutine(pParse,
p, &destB, pDest, regOutB,
regPrev, pKeyDup, P4_KEYINFO_STATIC, labelEnd);
}
/* Generate a subroutine to run when the results from select A
** are exhausted and only data in select B remains.
*/
VdbeNoopComment((v, "eof-A subroutine"));
if( op==TK_EXCEPT || op==TK_INTERSECT ){
addrEofA = sqlite3VdbeAddOp2(v, OP_Goto, 0, labelEnd);
}else{
addrEofA = sqlite3VdbeAddOp2(v, OP_If, regEofB, labelEnd);
sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofA);
}
/* Generate a subroutine to run when the results from select B
** are exhausted and only data in select A remains.
*/
if( op==TK_INTERSECT ){
addrEofB = addrEofA;
}else{
VdbeNoopComment((v, "eof-B subroutine"));
addrEofB = sqlite3VdbeAddOp2(v, OP_If, regEofA, labelEnd);
sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofB);
}
/* Generate code to handle the case of A<B
*/
VdbeNoopComment((v, "A-lt-B subroutine"));
addrAltB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
/* Generate code to handle the case of A==B
*/
if( op==TK_ALL ){
addrAeqB = addrAltB;
}else if( op==TK_INTERSECT ){
addrAeqB = addrAltB;
addrAltB++;
( run in 1.223 second using v1.01-cache-2.11-cpan-39bf76dae61 )