DBD-SQLeet
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** checks on every opcode. This helps sqlite3_step() to run about 1.5%
** faster according to "valgrind --tool=cachegrind" */
check_for_interrupt:
if( db->u1.isInterrupted ) goto abort_due_to_interrupt;
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
/* Call the progress callback if it is configured and the required number
** of VDBE ops have been executed (either since this invocation of
** sqlite3VdbeExec() or since last time the progress callback was called).
** If the progress callback returns non-zero, exit the virtual machine with
** a return code SQLITE_ABORT.
*/
if( nVmStep>=nProgressLimit && db->xProgress!=0 ){
assert( db->nProgressOps!=0 );
nProgressLimit = nVmStep + db->nProgressOps - (nVmStep%db->nProgressOps);
if( db->xProgress(db->pProgressArg) ){
rc = SQLITE_INTERRUPT;
goto abort_due_to_error;
}
}
#endif
break;
}
/* Opcode: Gosub P1 P2 * * *
**
** Write the current address onto register P1
** and then jump to address P2.
*/
case OP_Gosub: { /* jump */
assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
pIn1 = &aMem[pOp->p1];
assert( VdbeMemDynamic(pIn1)==0 );
memAboutToChange(p, pIn1);
pIn1->flags = MEM_Int;
pIn1->u.i = (int)(pOp-aOp);
REGISTER_TRACE(pOp->p1, pIn1);
/* Most jump operations do a goto to this spot in order to update
** the pOp pointer. */
jump_to_p2:
pOp = &aOp[pOp->p2 - 1];
break;
}
/* Opcode: Return P1 * * * *
**
** Jump to the next instruction after the address in register P1. After
** the jump, register P1 becomes undefined.
*/
case OP_Return: { /* in1 */
pIn1 = &aMem[pOp->p1];
assert( pIn1->flags==MEM_Int );
pOp = &aOp[pIn1->u.i];
pIn1->flags = MEM_Undefined;
break;
}
/* Opcode: InitCoroutine P1 P2 P3 * *
**
** Set up register P1 so that it will Yield to the coroutine
** located at address P3.
**
** If P2!=0 then the coroutine implementation immediately follows
** this opcode. So jump over the coroutine implementation to
** address P2.
**
** See also: EndCoroutine
*/
case OP_InitCoroutine: { /* jump */
assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
assert( pOp->p2>=0 && pOp->p2<p->nOp );
assert( pOp->p3>=0 && pOp->p3<p->nOp );
pOut = &aMem[pOp->p1];
assert( !VdbeMemDynamic(pOut) );
pOut->u.i = pOp->p3 - 1;
pOut->flags = MEM_Int;
if( pOp->p2 ) goto jump_to_p2;
break;
}
/* Opcode: EndCoroutine P1 * * * *
**
** The instruction at the address in register P1 is a Yield.
** Jump to the P2 parameter of that Yield.
** After the jump, register P1 becomes undefined.
**
** See also: InitCoroutine
*/
case OP_EndCoroutine: { /* in1 */
VdbeOp *pCaller;
pIn1 = &aMem[pOp->p1];
assert( pIn1->flags==MEM_Int );
assert( pIn1->u.i>=0 && pIn1->u.i<p->nOp );
pCaller = &aOp[pIn1->u.i];
assert( pCaller->opcode==OP_Yield );
assert( pCaller->p2>=0 && pCaller->p2<p->nOp );
pOp = &aOp[pCaller->p2 - 1];
pIn1->flags = MEM_Undefined;
break;
}
/* Opcode: Yield P1 P2 * * *
**
** Swap the program counter with the value in register P1. This
** has the effect of yielding to a coroutine.
**
** If the coroutine that is launched by this instruction ends with
** Yield or Return then continue to the next instruction. But if
** the coroutine launched by this instruction ends with
** EndCoroutine, then jump to P2 rather than continuing with the
** next instruction.
**
** See also: InitCoroutine
*/
case OP_Yield: { /* in1, jump */
int pcDest;
pIn1 = &aMem[pOp->p1];
assert( VdbeMemDynamic(pIn1)==0 );
pIn1->flags = MEM_Int;
pcDest = (int)pIn1->u.i;
pIn1->u.i = (int)(pOp - aOp);
REGISTER_TRACE(pOp->p1, pIn1);
pOp = &aOp[pcDest];
break;
}
/* Opcode: HaltIfNull P1 P2 P3 P4 P5
** Synopsis: if r[P3]=null halt
**
** Check the value in register P3. If it is NULL then Halt using
** parameter P1, P2, and P4 as if this were a Halt instruction. If the
** value in register P3 is not NULL, then this routine is a no-op.
** The P5 parameter should be 1.
*/
case OP_HaltIfNull: { /* in3 */
pIn3 = &aMem[pOp->p3];
#ifdef SQLITE_DEBUG
if( pOp->p2==OE_Abort ){ sqlite3VdbeAssertAbortable(p); }
#endif
if( (pIn3->flags & MEM_Null)==0 ) break;
/* Fall through into OP_Halt */
}
/* Opcode: Halt P1 P2 * P4 P5
**
** Exit immediately. All open cursors, etc are closed
** automatically.
**
** P1 is the result code returned by sqlite3_exec(), sqlite3_reset(),
** or sqlite3_finalize(). For a normal halt, this should be SQLITE_OK (0).
** For errors, it can be some other value. If P1!=0 then P2 will determine
** whether or not to rollback the current transaction. Do not rollback
** if P2==OE_Fail. Do the rollback if P2==OE_Rollback. If P2==OE_Abort,
** then back out all changes that have occurred during this execution of the
** VDBE, but do not rollback the transaction.
**
** If P4 is not null then it is an error message string.
**
** P5 is a value between 0 and 4, inclusive, that modifies the P4 string.
**
** 0: (no change)
** 1: NOT NULL contraint failed: P4
** 2: UNIQUE constraint failed: P4
** 3: CHECK constraint failed: P4
** 4: FOREIGN KEY constraint failed: P4
**
** If P5 is not zero and P4 is NULL, then everything after the ":" is
** omitted.
**
** insert into TABLE (IDLIST) select
** insert into TABLE (IDLIST) default values
**
** The IDLIST following the table name is always optional. If omitted,
** then a list of all (non-hidden) columns for the table is substituted.
** The IDLIST appears in the pColumn parameter. pColumn is NULL if IDLIST
** is omitted.
**
** For the pSelect parameter holds the values to be inserted for the
** first two forms shown above. A VALUES clause is really just short-hand
** for a SELECT statement that omits the FROM clause and everything else
** that follows. If the pSelect parameter is NULL, that means that the
** DEFAULT VALUES form of the INSERT statement is intended.
**
** The code generated follows one of four templates. For a simple
** insert with data coming from a single-row VALUES clause, the code executes
** once straight down through. Pseudo-code follows (we call this
** the "1st template"):
**
** open write cursor to <table> and its indices
** put VALUES clause expressions into registers
** write the resulting record into <table>
** cleanup
**
** The three remaining templates assume the statement is of the form
**
** INSERT INTO <table> SELECT ...
**
** If the SELECT clause is of the restricted form "SELECT * FROM <table2>" -
** in other words if the SELECT pulls all columns from a single table
** and there is no WHERE or LIMIT or GROUP BY or ORDER BY clauses, and
** if <table2> and <table1> are distinct tables but have identical
** schemas, including all the same indices, then a special optimization
** is invoked that copies raw records from <table2> over to <table1>.
** See the xferOptimization() function for the implementation of this
** template. This is the 2nd template.
**
** open a write cursor to <table>
** open read cursor on <table2>
** transfer all records in <table2> over to <table>
** close cursors
** foreach index on <table>
** open a write cursor on the <table> index
** open a read cursor on the corresponding <table2> index
** transfer all records from the read to the write cursors
** close cursors
** end foreach
**
** The 3rd template is for when the second template does not apply
** and the SELECT clause does not read from <table> at any time.
** The generated code follows this template:
**
** X <- A
** goto B
** A: setup for the SELECT
** loop over the rows in the SELECT
** load values into registers R..R+n
** yield X
** end loop
** cleanup after the SELECT
** end-coroutine X
** B: open write cursor to <table> and its indices
** C: yield X, at 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 an intermediate table to store the results of
** the select. The template is like this:
**
** 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
** end co-routine R
** B: open temp table
** L: yield X, at 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 */
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 */
Upsert *pUpsert /* ON CONFLICT clauses for upsert, or NULL */
){
sqlite3 *db; /* The main database structure */
Table *pTab; /* The table to insert into. aka TABLE */
int i, j; /* 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 iDataCur = 0; /* VDBE cursor that is the main data repository */
int iIdxCur = 0; /* First index cursor */
int ipkColumn = -1; /* Column that is the INTEGER PRIMARY KEY */
int endOfLoop; /* Label for the end of the insertion loop */
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 */
SelectDest dest; /* Destination for SELECT on rhs of INSERT */
int iDb; /* Index of database holding TABLE */
u8 useTempTable = 0; /* Store SELECT results in intermediate table */
u8 appendFlag = 0; /* True if the insert is likely to be an append */
u8 withoutRowid; /* 0 for normal table. 1 for WITHOUT ROWID table */
u8 bIdListInOrder; /* True if IDLIST is in table order */
if( j==pTab->iPKey ){
ipkColumn = i; assert( !withoutRowid );
}
break;
}
}
if( j>=pTab->nCol ){
if( sqlite3IsRowid(pColumn->a[i].zName) && !withoutRowid ){
ipkColumn = i;
bIdListInOrder = 0;
}else{
sqlite3ErrorMsg(pParse, "table %S has no column named %s",
pTabList, 0, pColumn->a[i].zName);
pParse->checkSchema = 1;
goto insert_cleanup;
}
}
}
}
/* 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 or from a multi-row VALUES clause.
** Generate a co-routine to run the SELECT. */
int regYield; /* Register holding co-routine entry-point */
int addrTop; /* Top of the co-routine */
int rc; /* Result code */
regYield = ++pParse->nMem;
addrTop = sqlite3VdbeCurrentAddr(v) + 1;
sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, addrTop);
sqlite3SelectDestInit(&dest, SRT_Coroutine, regYield);
dest.iSdst = bIdListInOrder ? regData : 0;
dest.nSdst = pTab->nCol;
rc = sqlite3Select(pParse, pSelect, &dest);
regFromSelect = dest.iSdst;
if( rc || db->mallocFailed || pParse->nErr ) goto insert_cleanup;
sqlite3VdbeEndCoroutine(v, regYield);
sqlite3VdbeJumpHere(v, addrTop - 1); /* label B: */
assert( pSelect->pEList );
nColumn = pSelect->pEList->nExpr;
/* 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 output 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( pTrigger || readsTable(pParse, 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, goto M at EOF
** insert row from R..R+n into temp table
** goto L
** M: ...
*/
int regRec; /* Register to hold packed record */
int regTempRowid; /* Register to hold temp table ROWID */
int addrL; /* Label "L" */
srcTab = pParse->nTab++;
regRec = sqlite3GetTempReg(pParse);
regTempRowid = sqlite3GetTempReg(pParse);
sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
addrL = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm); VdbeCoverage(v);
sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regTempRowid);
sqlite3VdbeGoto(v, addrL);
sqlite3VdbeJumpHere(v, addrL);
sqlite3ReleaseTempReg(pParse, regRec);
sqlite3ReleaseTempReg(pParse, regTempRowid);
}
}else{
/* This is the case if the data for the INSERT is coming from a
** single-row VALUES clause
*/
NameContext sNC;
memset(&sNC, 0, sizeof(sNC));
sNC.pParse = pParse;
srcTab = -1;
assert( useTempTable==0 );
if( pList ){
nColumn = pList->nExpr;
if( sqlite3ResolveExprListNames(&sNC, pList) ){
goto insert_cleanup;
}
}else{
nColumn = 0;
}
}
/* If there is no IDLIST term but the table has an integer primary
** key, the set the ipkColumn variable to the integer primary key
** column index in the original table definition.
*/
if( pColumn==0 && nColumn>0 ){
ipkColumn = pTab->iPKey;
}
/* Make sure the number of columns in the source data matches the number
** of columns to be inserted into the table.
*/
for(i=0; i<pTab->nCol; i++){
nHidden += (IsHiddenColumn(&pTab->aCol[i]) ? 1 : 0);
}
if( pColumn==0 && nColumn && nColumn!=(pTab->nCol-nHidden) ){
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->pNext==0 );
nCol = p->pEList->nExpr;
pKeyInfo = sqlite3KeyInfoAlloc(db, nCol, 1);
if( !pKeyInfo ){
rc = SQLITE_NOMEM_BKPT;
goto multi_select_end;
}
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*)sqlite3KeyInfoRef(pKeyInfo),
P4_KEYINFO);
pLoop->addrOpenEphm[i] = -1;
}
}
sqlite3KeyInfoUnref(pKeyInfo);
}
multi_select_end:
pDest->iSdst = dest.iSdst;
pDest->nSdst = dest.nSdst;
sqlite3SelectDelete(db, pDelete);
return rc;
}
#endif /* SQLITE_OMIT_COMPOUND_SELECT */
/*
** Error message for when two or more terms of a compound select have different
** size result sets.
*/
SQLITE_PRIVATE void sqlite3SelectWrongNumTermsError(Parse *pParse, Select *p){
if( p->selFlags & SF_Values ){
sqlite3ErrorMsg(pParse, "all VALUES must have the same number of terms");
}else{
sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
" do not have the same number of result columns", selectOpName(p->op));
}
}
/*
** Code an output subroutine for a coroutine implementation of a
** SELECT statment.
**
** The data to be output is contained in pIn->iSdst. There are
** pIn->nSdst 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 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 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 addr1, addr2;
addr1 = sqlite3VdbeAddOp1(v, OP_IfNot, regPrev); VdbeCoverage(v);
addr2 = sqlite3VdbeAddOp4(v, OP_Compare, pIn->iSdst, regPrev+1, pIn->nSdst,
(char*)sqlite3KeyInfoRef(pKeyInfo), P4_KEYINFO);
sqlite3VdbeAddOp3(v, OP_Jump, addr2+2, iContinue, addr2+2); VdbeCoverage(v);
sqlite3VdbeJumpHere(v, addr1);
sqlite3VdbeAddOp3(v, OP_Copy, pIn->iSdst, regPrev+1, pIn->nSdst-1);
sqlite3VdbeAddOp2(v, OP_Integer, 1, regPrev);
}
if( pParse->db->mallocFailed ) return 0;
/* Suppress the first OFFSET entries if there is an OFFSET clause
*/
codeOffset(v, p->iOffset, iContinue);
assert( pDest->eDest!=SRT_Exists );
assert( pDest->eDest!=SRT_Table );
switch( pDest->eDest ){
/* Store the result as data using a unique key.
*/
case SRT_EphemTab: {
int r1 = sqlite3GetTempReg(pParse);
assert( pIn->nSdst==1 || pParse->nErr>0 ); testcase( pIn->nSdst!=1 );
sqlite3ExprCodeMove(pParse, pIn->iSdst, pDest->iSDParm, 1);
/* The LIMIT clause will jump out of the loop for us */
break;
}
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
/* The results are stored in a sequence of registers
** starting at pDest->iSdst. Then the co-routine yields.
*/
case SRT_Coroutine: {
if( pDest->iSdst==0 ){
pDest->iSdst = sqlite3GetTempRange(pParse, pIn->nSdst);
pDest->nSdst = pIn->nSdst;
}
sqlite3ExprCodeMove(pParse, pIn->iSdst, pDest->iSdst, pIn->nSdst);
sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
break;
}
/* If none of the above, then the result destination must be
** SRT_Output. This routine is never called with any other
** destination other than the ones handled above or SRT_Output.
**
** For SRT_Output, results are stored in a sequence of registers.
** Then the OP_ResultRow opcode is used to cause sqlite3_step() to
** return the next row of result.
*/
default: {
assert( pDest->eDest==SRT_Output );
sqlite3VdbeAddOp2(v, OP_ResultRow, pIn->iSdst, pIn->nSdst);
break;
}
}
/* Jump to the end of the loop if the LIMIT is reached.
*/
if( p->iLimit ){
sqlite3VdbeAddOp2(v, OP_DecrJumpZero, p->iLimit, iBreak); VdbeCoverage(v);
}
/* 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 regAddrB; /* Address register for select-B coroutine */
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 = 0; /* Address of the output-B subroutine */
int addrEofA; /* Address of the select-A-exhausted subroutine */
int addrEofA_noB; /* Alternate addrEofA if B is uninitialized */
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 addr1; /* Jump instructions that get retargetted */
int op; /* One of TK_ALL, TK_UNION, TK_EXCEPT, TK_INTERSECT */
KeyInfo *pKeyDup = 0; /* 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 */
assert( p->pOrderBy!=0 );
assert( pKeyDup==0 ); /* "Managed" code needs this. Ticket #3382. */
db = pParse->db;
v = pParse->pVdbe;
assert( v!=0 ); /* Already thrown the error if VDBE alloc failed */
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 );
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++){
struct ExprList_item *pItem;
for(j=0, pItem=pOrderBy->a; j<nOrderBy; j++, pItem++){
assert( pItem->u.x.iOrderByCol>0 );
if( pItem->u.x.iOrderByCol==i ) break;
}
if( j==nOrderBy ){
Expr *pNew = sqlite3Expr(db, TK_INTEGER, 0);
if( pNew==0 ) return SQLITE_NOMEM_BKPT;
pNew->flags |= EP_IntValue;
pNew->u.iValue = i;
/* Reattach the ORDER BY clause to the query.
*/
p->pOrderBy = pOrderBy;
pPrior->pOrderBy = sqlite3ExprListDup(pParse->db, pOrderBy, 0);
/* 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 || db->mallocFailed );
regPrev = pParse->nMem+1;
pParse->nMem += nExpr+1;
sqlite3VdbeAddOp2(v, OP_Integer, 0, regPrev);
pKeyDup = sqlite3KeyInfoAlloc(db, nExpr, 1);
if( pKeyDup ){
assert( sqlite3KeyInfoIsWriteable(pKeyDup) );
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->pNext = 0;
sqlite3ResolveOrderGroupBy(pParse, p, p->pOrderBy, "ORDER");
if( pPrior->pPrior==0 ){
sqlite3ResolveOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, "ORDER");
}
/* 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;
regAddrA = ++pParse->nMem;
regAddrB = ++pParse->nMem;
regOutA = ++pParse->nMem;
regOutB = ++pParse->nMem;
sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB);
ExplainQueryPlan((pParse, 1, "MERGE (%s)", selectOpName(p->op)));
/* Generate a coroutine to evaluate the SELECT statement to the
** left of the compound operator - the "A" select.
*/
addrSelectA = sqlite3VdbeCurrentAddr(v) + 1;
addr1 = sqlite3VdbeAddOp3(v, OP_InitCoroutine, regAddrA, 0, addrSelectA);
VdbeComment((v, "left SELECT"));
pPrior->iLimit = regLimitA;
ExplainQueryPlan((pParse, 1, "LEFT"));
sqlite3Select(pParse, pPrior, &destA);
sqlite3VdbeEndCoroutine(v, regAddrA);
sqlite3VdbeJumpHere(v, addr1);
/* Generate a coroutine to evaluate the SELECT statement on
** the right - the "B" select
*/
addrSelectB = sqlite3VdbeCurrentAddr(v) + 1;
addr1 = sqlite3VdbeAddOp3(v, OP_InitCoroutine, regAddrB, 0, addrSelectB);
VdbeComment((v, "right SELECT"));
savedLimit = p->iLimit;
savedOffset = p->iOffset;
p->iLimit = regLimitB;
p->iOffset = 0;
ExplainQueryPlan((pParse, 1, "RIGHT"));
sqlite3Select(pParse, p, &destB);
p->iLimit = savedLimit;
p->iOffset = savedOffset;
sqlite3VdbeEndCoroutine(v, regAddrB);
/* 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, 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, labelEnd);
}
sqlite3KeyInfoUnref(pKeyDup);
/* Generate a subroutine to run when the results from select A
** are exhausted and only data in select B remains.
*/
if( op==TK_EXCEPT || op==TK_INTERSECT ){
addrEofA_noB = addrEofA = labelEnd;
}else{
VdbeNoopComment((v, "eof-A subroutine"));
addrEofA = sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
addrEofA_noB = sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, labelEnd);
VdbeCoverage(v);
sqlite3VdbeGoto(v, addrEofA);
p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow);
}
/* 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;
if( p->nSelectRow > pPrior->nSelectRow ) p->nSelectRow = pPrior->nSelectRow;
}else{
VdbeNoopComment((v, "eof-B subroutine"));
addrEofB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, labelEnd); VdbeCoverage(v);
sqlite3VdbeGoto(v, addrEofB);
}
( run in 0.791 second using v1.01-cache-2.11-cpan-39bf76dae61 )