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Overview
| Comment: | Remove an unused variable. Fix code that occurs before a variable declaration. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: | 01dc032b5bbd9c9ebb1965f176ca5d73 |
| User & Date: | drh 2012-10-09 01:39:25 |
Context
|
2012-10-09
| ||
| 09:26 | Bring some comments up to date in the query planner, and especially the ORDER BY optimizer. Also add testcase() macros. check-in: bb5c0f1c user: drh tags: trunk | |
| 01:39 | Remove an unused variable. Fix code that occurs before a variable declaration. check-in: 01dc032b user: drh tags: trunk | |
| 01:23 | Replace an always-false conditional with an assert(). check-in: 981b9943 user: drh tags: trunk | |
Changes
Changes to src/where.c.
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/* Loop over all indices looking for the best one to use
*/
for(; pProbe; pIdx=pProbe=pProbe->pNext){
const tRowcnt * const aiRowEst = pProbe->aiRowEst;
WhereCost pc; /* Cost of using pProbe */
double log10N = (double)1; /* base-10 logarithm of nRow (inexact) */
int bRev = 2; /* 0=forward scan. 1=reverse. 2=undecided */
WHERETRACE((
" %s(%s):\n",
pSrc->pTab->zName, (pIdx ? pIdx->zName : "ipk")
));
/* The following variables are populated based on the properties of
** index being evaluated. They are then used to determine the expected
** cost and number of rows returned.
**
** pc.plan.nEq:
** Number of equality terms that can be implemented using the index.
................................................................................
int nPriorSat; /* ORDER BY terms satisfied by outer loops */
int nOrderBy; /* Number of ORDER BY terms */
WhereTerm *pTerm; /* A single term of the WHERE clause */
#ifdef SQLITE_ENABLE_STAT3
WhereTerm *pFirstTerm = 0; /* First term matching the index */
#endif
memset(&pc, 0, sizeof(pc));
nOrderBy = p->pOrderBy ? p->pOrderBy->nExpr : 0;
if( p->i ){
nPriorSat = pc.plan.nOBSat = p->aLevel[p->i-1].plan.nOBSat;
bSort = nPriorSat<nOrderBy;
bDist = 0;
}else{
................................................................................
}
/* If there is an ORDER BY clause and the index being considered will
** naturally scan rows in the required order, set the appropriate flags
** in pc.plan.wsFlags. Otherwise, if there is an ORDER BY clause but
** the index will scan rows in a different order, set the bSort
** variable. */
assert( bRev>=0 && bRev<=2 );
if( bSort && (pSrc->jointype & JT_LEFT)==0 ){
int bRev = 2;
WHERETRACE((" --> before isSortingIndex: nPriorSat=%d\n",nPriorSat));
pc.plan.nOBSat = isSortingIndex(p, pProbe, iCur, &bRev);
WHERETRACE((" --> after isSortingIndex: bRev=%d nOBSat=%d\n",
bRev, pc.plan.nOBSat));
if( nPriorSat<pc.plan.nOBSat || (pc.plan.wsFlags & WHERE_UNIQUE)!=0 ){
|
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3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 .... 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 .... 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 |
/* Loop over all indices looking for the best one to use
*/
for(; pProbe; pIdx=pProbe=pProbe->pNext){
const tRowcnt * const aiRowEst = pProbe->aiRowEst;
WhereCost pc; /* Cost of using pProbe */
double log10N = (double)1; /* base-10 logarithm of nRow (inexact) */
/* The following variables are populated based on the properties of
** index being evaluated. They are then used to determine the expected
** cost and number of rows returned.
**
** pc.plan.nEq:
** Number of equality terms that can be implemented using the index.
................................................................................
int nPriorSat; /* ORDER BY terms satisfied by outer loops */
int nOrderBy; /* Number of ORDER BY terms */
WhereTerm *pTerm; /* A single term of the WHERE clause */
#ifdef SQLITE_ENABLE_STAT3
WhereTerm *pFirstTerm = 0; /* First term matching the index */
#endif
WHERETRACE((
" %s(%s):\n",
pSrc->pTab->zName, (pIdx ? pIdx->zName : "ipk")
));
memset(&pc, 0, sizeof(pc));
nOrderBy = p->pOrderBy ? p->pOrderBy->nExpr : 0;
if( p->i ){
nPriorSat = pc.plan.nOBSat = p->aLevel[p->i-1].plan.nOBSat;
bSort = nPriorSat<nOrderBy;
bDist = 0;
}else{
................................................................................
}
/* If there is an ORDER BY clause and the index being considered will
** naturally scan rows in the required order, set the appropriate flags
** in pc.plan.wsFlags. Otherwise, if there is an ORDER BY clause but
** the index will scan rows in a different order, set the bSort
** variable. */
if( bSort && (pSrc->jointype & JT_LEFT)==0 ){
int bRev = 2;
WHERETRACE((" --> before isSortingIndex: nPriorSat=%d\n",nPriorSat));
pc.plan.nOBSat = isSortingIndex(p, pProbe, iCur, &bRev);
WHERETRACE((" --> after isSortingIndex: bRev=%d nOBSat=%d\n",
bRev, pc.plan.nOBSat));
if( nPriorSat<pc.plan.nOBSat || (pc.plan.wsFlags & WHERE_UNIQUE)!=0 ){
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