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Overview
| Comment: | Fix comment typos in the where.c module. No code changes. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
1e0b77cf0edf3d26f76d83aa5466e9ec |
| User & Date: | drh 2013-08-30 17:50:35 |
Context
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2013-08-30
| ||
| 19:59 | Fix comment typo in analyze.c. No changes to code. (check-in: dbc31750 user: mistachkin tags: trunk) | |
| 17:50 | Fix comment typos in the where.c module. No code changes. (check-in: 1e0b77cf user: drh tags: trunk) | |
| 17:35 | If the cost of two whereLoop objects is the same in every way except that one has fewer expected output rows than the other, then choose the one with fewer output rows. (check-in: 79e458ef user: drh tags: trunk) | |
Changes
Changes to src/where.c.
181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 .... 4168 4169 4170 4171 4172 4173 4174 4175 4176 4177 4178 4179 4180 4181 4182 .... 4193 4194 4195 4196 4197 4198 4199 4200 4201 4202 4203 4204 4205 4206 4207 |
static int whereLoopResize(sqlite3*, WhereLoop*, int); /* ** Each instance of this object holds a sequence of WhereLoop objects ** that implement some or all of a query plan. ** ** Think of each WhereLoop object as a node in a graph with arcs ** showing dependences and costs for travelling between nodes. (That is ** not a completely accurate description because WhereLoop costs are a ** vector, not a scalar, and because dependences are many-to-one, not ** one-to-one as are graph nodes. But it is a useful visualization aid.) ** Then a WherePath object is a path through the graph that visits some ** or all of the WhereLoop objects once. ** ** The "solver" works by creating the N best WherePath objects of length ** 1. Then using those as a basis to compute the N best WherePath objects ** of length 2. And so forth until the length of WherePaths equals the ................................................................................ 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) dependences (2) setup-cost, (3) run-cost, and ** (4) number of output rows. */ assert( p->rSetup==pTemplate->rSetup ); if( p->nLTerm<pTemplate->nLTerm && (p->wsFlags & WHERE_INDEXED)!=0 && (pTemplate->wsFlags & WHERE_INDEXED)!=0 && p->u.btree.pIndex==pTemplate->u.btree.pIndex && p->prereq==pTemplate->prereq ................................................................................ } if( (p->prereq & pTemplate->prereq)==pTemplate->prereq && p->rRun>=pTemplate->rRun && p->nOut>=pTemplate->nOut && ALWAYS(p->rSetup>=pTemplate->rSetup) /* See SETUP-INVARIANT above */ ){ /* Overwrite an existing WhereLoop with a better one: one that is ** better at one of (1) dependences, (2) setup-cost, (3) run-cost ** or (4) number of output rows, and is no worse in any of those ** categories. */ pNext = p->pNextLoop; break; } } |
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181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 .... 4168 4169 4170 4171 4172 4173 4174 4175 4176 4177 4178 4179 4180 4181 4182 .... 4193 4194 4195 4196 4197 4198 4199 4200 4201 4202 4203 4204 4205 4206 4207 |
static int whereLoopResize(sqlite3*, WhereLoop*, int); /* ** Each instance of this object holds a sequence of WhereLoop objects ** that implement some or all of a query plan. ** ** Think of each WhereLoop object as a node in a graph with arcs ** showing dependencies and costs for travelling between nodes. (That is ** not a completely accurate description because WhereLoop costs are a ** vector, not a scalar, and because dependencies are many-to-one, not ** one-to-one as are graph nodes. But it is a useful visualization aid.) ** Then a WherePath object is a path through the graph that visits some ** or all of the WhereLoop objects once. ** ** The "solver" works by creating the N best WherePath objects of length ** 1. Then using those as a basis to compute the N best WherePath objects ** of length 2. And so forth until the length of WherePaths equals the ................................................................................ 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->nLTerm<pTemplate->nLTerm && (p->wsFlags & WHERE_INDEXED)!=0 && (pTemplate->wsFlags & WHERE_INDEXED)!=0 && p->u.btree.pIndex==pTemplate->u.btree.pIndex && p->prereq==pTemplate->prereq ................................................................................ } if( (p->prereq & pTemplate->prereq)==pTemplate->prereq && p->rRun>=pTemplate->rRun && p->nOut>=pTemplate->nOut && ALWAYS(p->rSetup>=pTemplate->rSetup) /* See SETUP-INVARIANT above */ ){ /* 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. */ pNext = p->pNextLoop; break; } } |