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Experimental opimizations to speed up FK constraint CASCADE and SET NULL action processing.

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FossilOrigin-Name: 35a20a5f22245c70faa51965951e8cc011defa93
This commit is contained in:
dan
2014-12-16 20:13:30 +00:00
parent 58cca03ce5
commit 0466883300
5 changed files with 150 additions and 32 deletions
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63
src/fkey.c
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@@ -437,7 +437,7 @@ static void fkLookupParent(
OE_Abort, 0, P4_STATIC, P5_ConstraintFK);
}else{
if( nIncr>0 && pFKey->isDeferred==0 ){
sqlite3ParseToplevel(pParse)->mayAbort = 1;
sqlite3MayAbort(pParse);
}
sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
}
@@ -509,6 +509,10 @@ static Expr *exprTableColumn(
** code for an SQL UPDATE operation, this function may be called twice -
** once to "delete" the old row and once to "insert" the new row.
**
** Parameter nIncr is passed -1 when inserting a row (as this may decrease
** the number of FK violations in the db) or +1 when deleting one (as this
** may increase the number of FK constraint problems).
**
** The code generated by this function scans through the rows in the child
** table that correspond to the parent table row being deleted or inserted.
** For each child row found, one of the following actions is taken:
@@ -629,9 +633,6 @@ static void fkScanChildren(
** each row found. Otherwise, for deferred constraints, increment the
** deferred constraint counter by nIncr for each row selected. */
pWInfo = sqlite3WhereBegin(pParse, pSrc, pWhere, 0, 0, 0, 0);
if( nIncr>0 && pFKey->isDeferred==0 ){
sqlite3ParseToplevel(pParse)->mayAbort = 1;
}
sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
if( pWInfo ){
sqlite3WhereEnd(pWInfo);
@@ -810,6 +811,24 @@ static int fkParentIsModified(
return 0;
}
/*
** Return true if the parser passed as the first argument is being
** used to code a trigger that is really a "SET NULL" action belonging
** to trigger pFKey.
*/
static int isSetNullAction(Parse *pParse, FKey *pFKey){
Parse *pTop = sqlite3ParseToplevel(pParse);
if( pTop->pTriggerPrg ){
Trigger *p = pTop->pTriggerPrg->pTrigger;
if( (p==pFKey->apTrigger[0] && pFKey->aAction[0]==OE_SetNull)
|| (p==pFKey->apTrigger[1] && pFKey->aAction[1]==OE_SetNull)
){
return 1;
}
}
return 0;
}
/*
** This function is called when inserting, deleting or updating a row of
** table pTab to generate VDBE code to perform foreign key constraint
@@ -862,7 +881,7 @@ void sqlite3FkCheck(
int *aiCol;
int iCol;
int i;
int isIgnore = 0;
int bIgnore = 0;
if( aChange
&& sqlite3_stricmp(pTab->zName, pFKey->zTo)!=0
@@ -921,7 +940,7 @@ void sqlite3FkCheck(
int rcauth;
char *zCol = pTo->aCol[pIdx ? pIdx->aiColumn[i] : pTo->iPKey].zName;
rcauth = sqlite3AuthReadCol(pParse, pTo->zName, zCol, iDb);
isIgnore = (rcauth==SQLITE_IGNORE);
bIgnore = (rcauth==SQLITE_IGNORE);
}
#endif
}
@@ -936,12 +955,18 @@ void sqlite3FkCheck(
/* A row is being removed from the child table. Search for the parent.
** If the parent does not exist, removing the child row resolves an
** outstanding foreign key constraint violation. */
fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regOld, -1,isIgnore);
fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regOld, -1, bIgnore);
}
if( regNew!=0 ){
if( regNew!=0 && !isSetNullAction(pParse, pFKey) ){
/* A row is being added to the child table. If a parent row cannot
** be found, adding the child row has violated the FK constraint. */
fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regNew, +1,isIgnore);
** be found, adding the child row has violated the FK constraint.
**
** If this operation is being performed as part of a trigger program
** that is actually a "SET NULL" action belonging to this very
** foreign key, then omit this scan altogether. As the child keys
** values are guaranteed to be NULL, it is not possible for adding
** this row to cause an FK violation. */
fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regNew, +1, bIgnore);
}
sqlite3DbFree(db, aiFree);
@@ -962,8 +987,8 @@ void sqlite3FkCheck(
&& !pParse->pToplevel && !pParse->isMultiWrite
){
assert( regOld==0 && regNew!=0 );
/* Inserting a single row into a parent table cannot cause an immediate
** foreign key violation. So do nothing in this case. */
/* Inserting a single row into a parent table cannot cause (or fix)
** an immediate foreign key violation. So do nothing in this case. */
continue;
}
@@ -987,13 +1012,15 @@ void sqlite3FkCheck(
fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regNew, -1);
}
if( regOld!=0 ){
/* If there is a RESTRICT action configured for the current operation
** on the parent table of this FK, then throw an exception
** immediately if the FK constraint is violated, even if this is a
** deferred trigger. That's what RESTRICT means. To defer checking
** the constraint, the FK should specify NO ACTION (represented
** using OE_None). NO ACTION is the default. */
int eAction = pFKey->aAction[aChange!=0];
fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regOld, 1);
/* If this is a deferred FK constraint, or a CASCADE or SET NULL
** action applies, do not set the may-abort flag on this statement.
** The flag may be set on this statement for some other reason, but
** not as a result of this FK constraint. */
if( !pFKey->isDeferred && eAction!=OE_Cascade && eAction!=OE_SetNull ){
sqlite3MayAbort(pParse);
}
}
pItem->zName = 0;
sqlite3SrcListDelete(db, pSrc);