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Factor out the code that generates a co-routine for evaluating the SELECT

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on the RHS of an INSERT statement so that the same code can potentially
be reused in other places.

FossilOrigin-Name: a93ee09cdc15987848bf9023e69892ce9a5f989e
This commit is contained in:
drh 2012-09-15 13:29:23 +00:00
parent 6ec6549158
commit 5f08526937
4 changed files with 105 additions and 52 deletions
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14
manifest
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@ -1,5 +1,5 @@
C Improved\salignment\sof\sfields\sin\sthe\sExpr\sobject\sgives\san\s8-byte\ssize\nreduction\son\s64-bit\smachines.
D 2012-09-13T19:59:09.165
C Factor\sout\sthe\scode\sthat\sgenerates\sa\sco-routine\sfor\sevaluating\sthe\sSELECT\non\sthe\sRHS\sof\san\sINSERT\sstatement\sso\sthat\sthe\ssame\scode\scan\spotentially\nbe\sreused\sin\sother\splaces.
D 2012-09-15T13:29:23.328
F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
F Makefile.in 5f4f26109f9d80829122e0e09f9cda008fa065fb
F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@ -138,7 +138,7 @@ F src/global.c 4cfdca5cb0edd33c4d021baec4ede958cb2c793b
F src/hash.c a4031441741932da9e7a65bee2b36b5d0e81c073
F src/hash.h 2894c932d84d9f892d4b4023a75e501f83050970
F src/hwtime.h d32741c8f4df852c7d959236615444e2b1063b08
F src/insert.c b090d0a9fb9ff2dbdeaf66aedccf98cd13b1af60
F src/insert.c 6e2aa7fbb5d4c5f34d412772751ed0aff0b9e87b
F src/journal.c 552839e54d1bf76fb8f7abe51868b66acacf6a0e
F src/legacy.c a199d7683d60cef73089e892409113e69c23a99f
F src/lempar.c 0ee69fca0be54cd93939df98d2aca4ca46f44416
@ -179,7 +179,7 @@ F src/shell.c 87953c5d9c73d9494db97d1607e2e2280418f261
F src/sqlite.h.in d1071b0fc6de9a0d11392bc01305803122c3ec61
F src/sqlite3.rc fea433eb0a59f4c9393c8e6d76a6e2596b1fe0c0
F src/sqlite3ext.h 6904f4aadf976f95241311fbffb00823075d9477
F src/sqliteInt.h 03ad3f925f07599cc39a7eebdb250c7f17fd57e6
F src/sqliteInt.h 0423f0a673e7365827584e86dfbab8c33cf32cf8
F src/sqliteLimit.h 164b0e6749d31e0daa1a4589a169d31c0dec7b3d
F src/status.c 35939e7e03abf1b7577ce311f48f682c40de3208
F src/table.c 2cd62736f845d82200acfa1287e33feb3c15d62e
@ -1013,7 +1013,7 @@ F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
F tool/win/sqlite.vsix 67d8a99aceb56384a81b3f30d6c71743146d2cc9
P 0ebe7cc57408d6d85910cc976fb8af4436d6e594
R b742c79022ff08cfe99db98bba004b78
P 6b252a0d1a78db7bf2d650bafc214ea4064eef9e
R df7cddb2132aa1a021f32020fc480477
U drh
Z 3cb58e8f20dd1433c3550c4182838eb5
Z c609d2d14d939fff56bf9fbc82b9e705

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@ -1 +1 @@
6b252a0d1a78db7bf2d650bafc214ea4064eef9e
a93ee09cdc15987848bf9023e69892ce9a5f989e

140
src/insert.c
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@ -320,6 +320,97 @@ void sqlite3AutoincrementEnd(Parse *pParse){
#endif /* SQLITE_OMIT_AUTOINCREMENT */
/*
** Generate code for a co-routine that will evaluate a subquery one
** row at a time.
**
** The pSelect parameter is the subquery that the co-routine will evaluation.
** Information about the location of co-routine and the registers it will use
** is returned by filling in the pDest object.
**
** Registers are allocated as follows:
**
** pDest->iSDParm The register holding the next entry-point of the
** 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.
**
** This routine handles all of the register allocation and fills in the
** pDest structure appropriately.
**
** Here is a schematic of the generated code assuming that X is the
** co-routine entry-point register reg[pDest->iSDParm], that EOF is the
** completed flag reg[pDest->iSDParm+1], and R and S are the range of
** registers that hold the result set, reg[pDest->iSdst] through
** reg[pDest->iSdst+pDest->nSdst-1]:
**
** X <- A
** EOF <- 0
** goto B
** A: setup for the SELECT
** loop rows in the SELECT
** load results into registers R..S
** yield X
** end loop
** cleanup after the SELECT
** EOF <- 1
** yield X
** halt-error
** B:
**
** To use this subroutine, the caller generates code as follows:
**
** [ Co-routine generated by this subroutine, shown above ]
** S: yield X
** if EOF goto E
** if skip this row, goto C
** if terminate loop, goto E
** deal with this row
** C: goto S
** E:
*/
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 */
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 */
sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_INTERNAL, OE_Abort);
VdbeComment((v, "End of coroutine"));
sqlite3VdbeJumpHere(v, j1); /* label B: */
return rc;
}
/* Forward declaration */
static int xferOptimization(
Parse *pParse, /* Parser context */
@ -568,51 +659,12 @@ void sqlite3Insert(
** 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.iSDParm);
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);
assert( pParse->nErr==0 || rc );
if( rc || NEVER(pParse->nErr) || db->mallocFailed ){
goto insert_cleanup;
}
sqlite3VdbeAddOp2(v, OP_Integer, 1, regEof); /* EOF <- 1 */
sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm); /* yield X */
sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_INTERNAL, OE_Abort);
VdbeComment((v, "End of SELECT coroutine"));
sqlite3VdbeJumpHere(v, j1); /* label B: */
/* Data is coming from a SELECT. Generate a co-routine to run that
** SELECT. */
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;

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src/sqliteInt.h
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@ -2780,6 +2780,7 @@ void sqlite3DeleteTable(sqlite3*, Table*);
# define sqlite3AutoincrementBegin(X)
# define sqlite3AutoincrementEnd(X)
#endif
int sqlite3CodeCoroutine(Parse*, Select*, SelectDest*);
void sqlite3Insert(Parse*, SrcList*, ExprList*, Select*, IdList*, int);
void *sqlite3ArrayAllocate(sqlite3*,void*,int,int*,int*);
IdList *sqlite3IdListAppend(sqlite3*, IdList*, Token*);