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Lines 4048-4053
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| 4048 |
int bestJ = -1; /* The value of j */ |
4048 |
int bestJ = -1; /* The value of j */ |
| 4049 |
Bitmask m; /* Bitmask value for j or bestJ */ |
4049 |
Bitmask m; /* Bitmask value for j or bestJ */ |
| 4050 |
int isOptimal; /* Iterator for optimal/non-optimal search */ |
4050 |
int isOptimal; /* Iterator for optimal/non-optimal search */ |
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|
4051 |
int nUnconstrained; /* Number tables without INDEXED BY */ |
| 4052 |
Bitmask notIndexed; /* Mask of tables that cannot use an index */ |
| 4051 |
|
4053 |
|
| 4052 |
memset(&bestPlan, 0, sizeof(bestPlan)); |
4054 |
memset(&bestPlan, 0, sizeof(bestPlan)); |
| 4053 |
bestPlan.rCost = SQLITE_BIG_DBL; |
4055 |
bestPlan.rCost = SQLITE_BIG_DBL; |
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Lines 4089-4094
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| 4089 |
** algorithm may choose to use t2 for the outer loop, which is a much |
4091 |
** algorithm may choose to use t2 for the outer loop, which is a much |
| 4090 |
** costlier approach. |
4092 |
** costlier approach. |
| 4091 |
*/ |
4093 |
*/ |
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|
4094 |
nUnconstrained = 0; |
| 4095 |
notIndexed = 0; |
| 4092 |
for(isOptimal=(iFrom<nTabList-1); isOptimal>=0; isOptimal--){ |
4096 |
for(isOptimal=(iFrom<nTabList-1); isOptimal>=0; isOptimal--){ |
| 4093 |
Bitmask mask; /* Mask of tables not yet ready */ |
4097 |
Bitmask mask; /* Mask of tables not yet ready */ |
| 4094 |
for(j=iFrom, pTabItem=&pTabList->a[j]; j<nTabList; j++, pTabItem++){ |
4098 |
for(j=iFrom, pTabItem=&pTabList->a[j]; j<nTabList; j++, pTabItem++){ |
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Lines 4105-4110
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| 4105 |
} |
4109 |
} |
| 4106 |
mask = (isOptimal ? m : notReady); |
4110 |
mask = (isOptimal ? m : notReady); |
| 4107 |
pOrderBy = ((i==0 && ppOrderBy )?*ppOrderBy:0); |
4111 |
pOrderBy = ((i==0 && ppOrderBy )?*ppOrderBy:0); |
|
|
4112 |
if( pTabItem->pIndex==0 ) nUnconstrained++; |
| 4108 |
|
4113 |
|
| 4109 |
assert( pTabItem->pTab ); |
4114 |
assert( pTabItem->pTab ); |
| 4110 |
#ifndef SQLITE_OMIT_VIRTUALTABLE |
4115 |
#ifndef SQLITE_OMIT_VIRTUALTABLE |
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Lines 4118-4126
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| 4118 |
} |
4123 |
} |
| 4119 |
assert( isOptimal || (sCost.used¬Ready)==0 ); |
4124 |
assert( isOptimal || (sCost.used¬Ready)==0 ); |
| 4120 |
|
4125 |
|
| 4121 |
if( (sCost.used¬Ready)==0 |
4126 |
/* If an INDEXED BY clause is present, then the plan must use that |
| 4122 |
&& (bestJ<0 || sCost.rCost<bestPlan.rCost |
4127 |
** index if it uses any index at all */ |
| 4123 |
|| (sCost.rCost<=bestPlan.rCost && sCost.nRow<bestPlan.nRow)) |
4128 |
assert( pTabItem->pIndex==0 |
|
|
4129 |
|| (sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)==0 |
| 4130 |
|| sCost.plan.u.pIdx==pTabItem->pIndex ); |
| 4131 |
|
| 4132 |
if( isOptimal && (sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)==0 ){ |
| 4133 |
notIndexed |= m; |
| 4134 |
} |
| 4135 |
|
| 4136 |
/* Conditions under which this table becomes the best so far: |
| 4137 |
** |
| 4138 |
** (1) The table must not depend on other tables that have not |
| 4139 |
** yet run. |
| 4140 |
** |
| 4141 |
** (2) A full-table-scan plan cannot supercede another plan unless |
| 4142 |
** it is an "optimal" plan as defined above. |
| 4143 |
** |
| 4144 |
** (3) All tables have an INDEXED BY clause or this table lacks an |
| 4145 |
** INDEXED BY clause or this table uses the specific |
| 4146 |
** index specified by its INDEXED BY clause. This rule ensures |
| 4147 |
** that a best-so-far is always selected even if an impossible |
| 4148 |
** combination of INDEXED BY clauses are given. The error |
| 4149 |
** will be detected and relayed back to the application later. |
| 4150 |
** The NEVER() comes about because rule (2) above prevents |
| 4151 |
** An indexable full-table-scan from reaching rule (3). |
| 4152 |
** |
| 4153 |
** (4) The plan cost must be lower than prior plans or else the |
| 4154 |
** cost must be the same and the number of rows must be lower. |
| 4155 |
*/ |
| 4156 |
if( (sCost.used¬Ready)==0 /* (1) */ |
| 4157 |
&& (bestJ<0 || (notIndexed&m)!=0 /* (2) */ |
| 4158 |
|| (sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)!=0) |
| 4159 |
&& (nUnconstrained==0 || pTabItem->pIndex==0 /* (3) */ |
| 4160 |
|| NEVER((sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)!=0)) |
| 4161 |
&& (bestJ<0 || sCost.rCost<bestPlan.rCost /* (4) */ |
| 4162 |
|| (sCost.rCost<=bestPlan.rCost && sCost.nRow<bestPlan.nRow)) |
| 4124 |
){ |
4163 |
){ |
| 4125 |
WHERETRACE(("... best so far with cost=%g and nRow=%g\n", |
4164 |
WHERETRACE(("... best so far with cost=%g and nRow=%g\n", |
| 4126 |
sCost.rCost, sCost.nRow)); |
4165 |
sCost.rCost, sCost.nRow)); |
