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Add the OP_Undef and OP_IsUndef opcodes. With these, use the first register

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in the result register range as the flag to indicate EOF on an INSERT from
a SELECT, rather than allocating a separate boolean register for that task.

FossilOrigin-Name: 6fb7448550f28a3c93053e125faeaf11de1011d0
This commit is contained in:
drh
2014-02-07 13:20:31 +00:00
parent 21a919f630
commit a5750cfe01
7 changed files with 65 additions and 53 deletions
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45
src/insert.c
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@@ -349,17 +349,13 @@ void sqlite3AutoincrementEnd(Parse *pParse){
** co-routine. Run the co-routine to its next breakpoint
** by calling "OP_Yield $X" where $X is pDest->iSDParm.
**
** pDest->iSDParm+1 The register holding the "completed" flag for the
** co-routine. This register is 0 if the previous Yield
** generated a new result row, or 1 if the subquery
** has completed. If the Yield is called again
** after this register becomes 1, then the VDBE will
** halt with an SQLITE_INTERNAL error.
**
** pDest->iSdst First result register.
**
** pDest->nSdst Number of result registers.
**
** At EOF the first result register will be marked as "undefined" so that
** the caller can know when to stop reading results.
**
** This routine handles all of the register allocation and fills in the
** pDest structure appropriately.
**
@@ -370,7 +366,6 @@ void sqlite3AutoincrementEnd(Parse *pParse){
** reg[pDest->iSdst+pDest->nSdst-1]:
**
** X <- A
** EOF <- 0
** goto B
** A: setup for the SELECT
** loop rows in the SELECT
@@ -378,7 +373,7 @@ void sqlite3AutoincrementEnd(Parse *pParse){
** yield X
** end loop
** cleanup after the SELECT
** EOF <- 1
** R <- undefined (signals EOF)
** yield X
** halt-error
** B:
@@ -387,7 +382,7 @@ void sqlite3AutoincrementEnd(Parse *pParse){
**
** [ Co-routine generated by this subroutine, shown above ]
** S: yield X
** if EOF goto E
** if R==undefined goto E
** if skip this row, goto C
** if terminate loop, goto E
** deal with this row
@@ -396,28 +391,24 @@ void sqlite3AutoincrementEnd(Parse *pParse){
*/
int sqlite3CodeCoroutine(Parse *pParse, Select *pSelect, SelectDest *pDest){
int regYield; /* Register holding co-routine entry-point */
int regEof; /* Register holding co-routine completion flag */
int addrTop; /* Top of the co-routine */
int j1; /* Jump instruction */
int rc; /* Result code */
Vdbe *v; /* VDBE under construction */
regYield = ++pParse->nMem;
regEof = ++pParse->nMem;
v = sqlite3GetVdbe(pParse);
addrTop = sqlite3VdbeCurrentAddr(v);
sqlite3VdbeAddOp2(v, OP_Integer, addrTop+2, regYield); /* X <- A */
sqlite3VdbeAddOp2(v, OP_Integer, addrTop+1, regYield); /* X <- A */
VdbeComment((v, "Co-routine entry point"));
sqlite3VdbeAddOp2(v, OP_Integer, 0, regEof); /* EOF <- 0 */
VdbeComment((v, "Co-routine completion flag"));
sqlite3SelectDestInit(pDest, SRT_Coroutine, regYield);
j1 = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
rc = sqlite3Select(pParse, pSelect, pDest);
assert( pParse->nErr==0 || rc );
if( pParse->db->mallocFailed && rc==SQLITE_OK ) rc = SQLITE_NOMEM;
if( rc ) return rc;
sqlite3VdbeAddOp2(v, OP_Integer, 1, regEof); /* EOF <- 1 */
sqlite3VdbeAddOp1(v, OP_Yield, regYield); /* yield X */
sqlite3VdbeAddOp1(v, OP_Undef, pDest->iSdst); /* Signal EOF */
sqlite3VdbeAddOp1(v, OP_Yield, regYield); /* yield X */
sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_INTERNAL, OE_Abort);
VdbeComment((v, "End of coroutine"));
sqlite3VdbeJumpHere(v, j1); /* label B: */
@@ -488,7 +479,6 @@ static int xferOptimization(
** and the SELECT clause does not read from <table> at any time.
** The generated code follows this template:
**
** EOF <- 0
** X <- A
** goto B
** A: setup for the SELECT
@@ -497,12 +487,12 @@ static int xferOptimization(
** yield X
** end loop
** cleanup after the SELECT
** EOF <- 1
** R <- undefined (signals EOF)
** yield X
** goto A
** B: open write cursor to <table> and its indices
** C: yield X
** if EOF goto D
** if R=undefined goto D
** insert the select result into <table> from R..R+n
** goto C
** D: cleanup
@@ -513,7 +503,6 @@ static int xferOptimization(
** 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
@@ -522,12 +511,12 @@ static int xferOptimization(
** yield X
** end loop
** cleanup after the SELECT
** EOF <- 1
** R <- undefined (signals EOF)
** yield X
** halt-error
** B: open temp table
** L: yield X
** if EOF goto M
** if R=undefined goto M
** insert row from R..R+n into temp table
** goto L
** M: open write cursor to <table> and its indices
@@ -576,7 +565,6 @@ void sqlite3Insert(
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 regEof = 0; /* Register recording end of SELECT data */
int *aRegIdx = 0; /* One register allocated to each index */
#ifndef SQLITE_OMIT_TRIGGER
@@ -689,7 +677,6 @@ void sqlite3Insert(
int rc = sqlite3CodeCoroutine(pParse, pSelect, &dest);
if( rc ) goto insert_cleanup;
regEof = dest.iSDParm + 1;
regFromSelect = dest.iSdst;
assert( pSelect->pEList );
nColumn = pSelect->pEList->nExpr;
@@ -715,7 +702,7 @@ void sqlite3Insert(
**
** B: open temp table
** L: yield X
** if EOF goto M
** if R=undefined goto M
** insert row from R..R+n into temp table
** goto L
** M: ...
@@ -730,7 +717,7 @@ void sqlite3Insert(
regTempRowid = sqlite3GetTempReg(pParse);
sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
addrTop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
addrIf = sqlite3VdbeAddOp1(v, OP_If, regEof);
addrIf = sqlite3VdbeAddOp1(v, OP_IsUndef, regFromSelect);
sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regTempRowid);
@@ -860,13 +847,13 @@ void sqlite3Insert(
** following pseudocode (template 3):
**
** C: yield X
** if EOF goto D
** if R=undefined goto D
** insert the select result into <table> from R..R+n
** goto C
** D: ...
*/
addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
addrInsTop = sqlite3VdbeAddOp1(v, OP_If, regEof);
addrInsTop = sqlite3VdbeAddOp1(v, OP_IsUndef, dest.iSdst);
}
/* Allocate registers for holding the rowid of the new row,