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Merge the latest trunk changes into the threads branch.

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FossilOrigin-Name: 39ac79cffe716f88af0871bdd206231b6a6511ff
This commit is contained in:
drh
2014-04-04 18:37:36 +00:00
parent 8daefc2af0 853546d047
commit 85462ed939
6 changed files with 322 additions and 85 deletions
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3
src/pager.c
View File

@@ -1624,12 +1624,11 @@ static int writeMasterJournal(Pager *pPager, const char *zMaster){
if( !zMaster
|| pPager->journalMode==PAGER_JOURNALMODE_MEMORY
|| pPager->journalMode==PAGER_JOURNALMODE_OFF
|| !isOpen(pPager->jfd)
){
return SQLITE_OK;
}
pPager->setMaster = 1;
assert( isOpen(pPager->jfd) );
assert( pPager->journalHdr <= pPager->journalOff );
/* Calculate the length in bytes and the checksum of zMaster */

231
src/where.c
View File

@@ -3711,6 +3711,124 @@ static void whereInfoFree(sqlite3 *db, WhereInfo *pWInfo){
}
}
/*
** Return TRUE if the set of WHERE clause terms used by pA is a proper
** subset of the WHERE clause terms used by pB.
*/
static int whereLoopProperSubset(const WhereLoop *pA, const WhereLoop *pB){
int i, j;
assert( pA->nLTerm<pB->nLTerm ); /* Checked by calling function */
for(j=0, i=pA->nLTerm-1; i>=0 && j>=0; i--){
for(j=pB->nLTerm-1; j>=0; j--){
if( pB->aLTerm[j]==pA->aLTerm[i] ) break;
}
}
return j>=0;
}
/*
** Try to adjust the cost of WhereLoop pTemplate upwards or downwards so
** that:
**
** (1) pTemplate costs less than any other WhereLoops that are a proper
** subset of pTemplate
**
** (2) pTemplate costs more than any other WhereLoops for which pTemplate
** is a proper subset.
**
** To say "WhereLoop X is a proper subset of Y" means that X uses fewer
** WHERE clause terms than Y and that every WHERE clause term used by X is
** also used by Y.
*/
static void whereLoopAdjustCost(const WhereLoop *p, WhereLoop *pTemplate){
if( (pTemplate->wsFlags & WHERE_INDEXED)==0 ) return;
for(; p; p=p->pNextLoop){
if( p->iTab!=pTemplate->iTab ) continue;
if( (p->wsFlags & WHERE_INDEXED)==0 ) continue;
if( p->nLTerm<pTemplate->nLTerm
&& (p->rRun<pTemplate->rRun || (p->rRun==pTemplate->rRun &&
p->nOut<=pTemplate->nOut))
&& whereLoopProperSubset(p, pTemplate)
){
pTemplate->rRun = p->rRun;
pTemplate->nOut = p->nOut - 1;
}else
if( p->nLTerm>pTemplate->nLTerm
&& (p->rRun>pTemplate->rRun || (p->rRun==pTemplate->rRun &&
p->nOut>=pTemplate->nOut))
&& whereLoopProperSubset(pTemplate, p)
){
pTemplate->rRun = p->rRun;
pTemplate->nOut = p->nOut + 1;
}
}
}
/*
** Search the list of WhereLoops in *ppPrev looking for one that can be
** supplanted by pTemplate.
**
** Return NULL if the WhereLoop list contains an entry that can supplant
** pTemplate, in other words if pTemplate does not belong on the list.
**
** If pX is a WhereLoop that pTemplate can supplant, then return the
** link that points to pX.
**
** If pTemplate cannot supplant any existing element of the list but needs
** to be added to the list, then return a pointer to the tail of the list.
*/
static WhereLoop **whereLoopFindLesser(
WhereLoop **ppPrev,
const WhereLoop *pTemplate
){
WhereLoop *p;
for(p=(*ppPrev); p; ppPrev=&p->pNextLoop, p=*ppPrev){
if( p->iTab!=pTemplate->iTab || p->iSortIdx!=pTemplate->iSortIdx ){
/* If either the iTab or iSortIdx values for two WhereLoop are different
** then those WhereLoops need to be considered separately. Neither is
** a candidate to replace the other. */
continue;
}
/* In the current implementation, the rSetup value is either zero
** or the cost of building an automatic index (NlogN) and the NlogN
** is the same for compatible WhereLoops. */
assert( p->rSetup==0 || pTemplate->rSetup==0
|| p->rSetup==pTemplate->rSetup );
/* whereLoopAddBtree() always generates and inserts the automatic index
** case first. Hence compatible candidate WhereLoops never have a larger
** rSetup. Call this SETUP-INVARIANT */
assert( p->rSetup>=pTemplate->rSetup );
/* If existing WhereLoop p is better than pTemplate, pTemplate can be
** discarded. WhereLoop p is better if:
** (1) p has no more dependencies than pTemplate, and
** (2) p has an equal or lower cost than pTemplate
*/
if( (p->prereq & pTemplate->prereq)==p->prereq /* (1) */
&& p->rSetup<=pTemplate->rSetup /* (2a) */
&& p->rRun<=pTemplate->rRun /* (2b) */
&& p->nOut<=pTemplate->nOut /* (2c) */
){
return 0; /* Discard pTemplate */
}
/* If pTemplate is always better than p, then cause p to be overwritten
** with pTemplate. pTemplate is better than p if:
** (1) pTemplate has no more dependences than p, and
** (2) pTemplate has an equal or lower cost than p.
*/
if( (p->prereq & pTemplate->prereq)==pTemplate->prereq /* (1) */
&& p->rRun>=pTemplate->rRun /* (2a) */
&& p->nOut>=pTemplate->nOut /* (2b) */
){
assert( p->rSetup>=pTemplate->rSetup ); /* SETUP-INVARIANT above */
break; /* Cause p to be overwritten by pTemplate */
}
}
return ppPrev;
}
/*
** Insert or replace a WhereLoop entry using the template supplied.
**
@@ -3720,25 +3838,23 @@ static void whereInfoFree(sqlite3 *db, WhereInfo *pWInfo){
** fewer dependencies than the template. Otherwise a new WhereLoop is
** added based on the template.
**
** If pBuilder->pOrSet is not NULL then we only care about only the
** If pBuilder->pOrSet is not NULL then we care about only the
** prerequisites and rRun and nOut costs of the N best loops. That
** information is gathered in the pBuilder->pOrSet object. This special
** processing mode is used only for OR clause processing.
**
** When accumulating multiple loops (when pBuilder->pOrSet is NULL) we
** still might overwrite similar loops with the new template if the
** template is better. Loops may be overwritten if the following
** new template is better. Loops may be overwritten if the following
** conditions are met:
**
** (1) They have the same iTab.
** (2) They have the same iSortIdx.
** (3) The template has same or fewer dependencies than the current loop
** (4) The template has the same or lower cost than the current loop
** (5) The template uses more terms of the same index but has no additional
** dependencies
*/
static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){
WhereLoop **ppPrev, *p, *pNext = 0;
WhereLoop **ppPrev, *p;
WhereInfo *pWInfo = pBuilder->pWInfo;
sqlite3 *db = pWInfo->pParse->db;
@@ -3761,64 +3877,23 @@ static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){
return SQLITE_OK;
}
/* Search for an existing WhereLoop to overwrite, or which takes
** priority over pTemplate.
/* Look for an existing WhereLoop to replace with pTemplate
*/
for(ppPrev=&pWInfo->pLoops, p=*ppPrev; p; ppPrev=&p->pNextLoop, p=*ppPrev){
if( p->iTab!=pTemplate->iTab || p->iSortIdx!=pTemplate->iSortIdx ){
/* If either the iTab or iSortIdx values for two WhereLoop are different
** then those WhereLoops need to be considered separately. Neither is
** a candidate to replace the other. */
continue;
}
/* In the current implementation, the rSetup value is either zero
** or the cost of building an automatic index (NlogN) and the NlogN
** is the same for compatible WhereLoops. */
assert( p->rSetup==0 || pTemplate->rSetup==0
|| p->rSetup==pTemplate->rSetup );
whereLoopAdjustCost(pWInfo->pLoops, pTemplate);
ppPrev = whereLoopFindLesser(&pWInfo->pLoops, pTemplate);
/* whereLoopAddBtree() always generates and inserts the automatic index
** case first. Hence compatible candidate WhereLoops never have a larger
** rSetup. Call this SETUP-INVARIANT */
assert( p->rSetup>=pTemplate->rSetup );
if( (p->prereq & pTemplate->prereq)==p->prereq
&& p->rSetup<=pTemplate->rSetup
&& p->rRun<=pTemplate->rRun
&& p->nOut<=pTemplate->nOut
){
/* This branch taken when p is equal or better than pTemplate in
** all of (1) dependencies (2) setup-cost, (3) run-cost, and
** (4) number of output rows. */
assert( p->rSetup==pTemplate->rSetup );
if( p->prereq==pTemplate->prereq
&& p->nLTerm<pTemplate->nLTerm
&& (p->wsFlags & pTemplate->wsFlags & WHERE_INDEXED)!=0
&& (p->u.btree.pIndex==pTemplate->u.btree.pIndex
|| pTemplate->rRun+p->nLTerm<=p->rRun+pTemplate->nLTerm)
){
/* Overwrite an existing WhereLoop with an similar one that uses
** more terms of the index */
pNext = p->pNextLoop;
break;
}else{
/* pTemplate is not helpful.
** Return without changing or adding anything */
goto whereLoopInsert_noop;
}
}
if( (p->prereq & pTemplate->prereq)==pTemplate->prereq
&& p->rRun>=pTemplate->rRun
&& p->nOut>=pTemplate->nOut
){
/* Overwrite an existing WhereLoop with a better one: one that is
** better at one of (1) dependencies, (2) setup-cost, (3) run-cost
** or (4) number of output rows, and is no worse in any of those
** categories. */
assert( p->rSetup>=pTemplate->rSetup ); /* SETUP-INVARIANT above */
pNext = p->pNextLoop;
break;
if( ppPrev==0 ){
/* There already exists a WhereLoop on the list that is better
** than pTemplate, so just ignore pTemplate */
#if WHERETRACE_ENABLED /* 0x8 */
if( sqlite3WhereTrace & 0x8 ){
sqlite3DebugPrintf("ins-noop: ");
whereLoopPrint(pTemplate, pBuilder->pWC);
}
#endif
return SQLITE_OK;
}else{
p = *ppPrev;
}
/* If we reach this point it means that either p[] should be overwritten
@@ -3836,13 +3911,33 @@ static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){
}
#endif
if( p==0 ){
p = sqlite3DbMallocRaw(db, sizeof(WhereLoop));
/* Allocate a new WhereLoop to add to the end of the list */
*ppPrev = p = sqlite3DbMallocRaw(db, sizeof(WhereLoop));
if( p==0 ) return SQLITE_NOMEM;
whereLoopInit(p);
p->pNextLoop = 0;
}else{
/* We will be overwriting WhereLoop p[]. But before we do, first
** go through the rest of the list and delete any other entries besides
** p[] that are also supplated by pTemplate */
WhereLoop **ppTail = &p->pNextLoop;
WhereLoop *pToDel;
while( *ppTail ){
ppTail = whereLoopFindLesser(ppTail, pTemplate);
if( NEVER(ppTail==0) ) break;
pToDel = *ppTail;
if( pToDel==0 ) break;
*ppTail = pToDel->pNextLoop;
#if WHERETRACE_ENABLED /* 0x8 */
if( sqlite3WhereTrace & 0x8 ){
sqlite3DebugPrintf("ins-del: ");
whereLoopPrint(pToDel, pBuilder->pWC);
}
#endif
whereLoopDelete(db, pToDel);
}
}
whereLoopXfer(db, p, pTemplate);
p->pNextLoop = pNext;
*ppPrev = p;
if( (p->wsFlags & WHERE_VIRTUALTABLE)==0 ){
Index *pIndex = p->u.btree.pIndex;
if( pIndex && pIndex->tnum==0 ){
@@ -3850,16 +3945,6 @@ static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){
}
}
return SQLITE_OK;
/* Jump here if the insert is a no-op */
whereLoopInsert_noop:
#if WHERETRACE_ENABLED /* 0x8 */
if( sqlite3WhereTrace & 0x8 ){
sqlite3DebugPrintf("ins-noop: ");
whereLoopPrint(pTemplate, pBuilder->pWC);
}
#endif
return SQLITE_OK;
}
/*