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Overview
| Comment: | Evaluate WHERE clause terms that reference only the index before evaluating terms that require the table, and thereby avoid seeking the table row if index terms are false. This is called the "push-down" optimization in the MySQL world, we are told. Do not confuse with WHERE-clause push-down. |
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| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
d7bb79ed3a40419d143fbe35c310e51f |
| User & Date: | drh 2017-04-29 15:27:04.896 |
| Original Comment: | Evaluate WHERE clause terms that reference only the index before evaluating terms that require the table, and thereby avoid seeking the table row if index terms are false. This is called the "push-down" optimization in the MySQL world, we are told. |
References
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2017-07-10
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| 17:00 | When multiple constraints need to be evaluated for a row, do any constraints that involve correlated subqueries last. Hence, the priority is index-covered constraints first, correlated subquery constraints last, and all others in the middle. This is a follow-on and improvement to the push-down optimization of check-in [d7bb79ed]. (check-in: c4cb90487f user: drh tags: trunk) | |
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2015-06-02
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| 18:09 | For FROM-clause subqueries that cannot be flattened, try to push relevant WHERE clause terms of the outer query down into the subquery in order to help the subquery run faster and/or use less memory. Call this the "WHERE-clause push-down optimization". Do not confuse this with the completely different MySQL push-down optimization. (check-in: 6df18e949d user: drh tags: trunk) | |
Context
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2017-04-29
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| 20:53 | Automatically transfer terms from the HAVING clause to the WHERE clause of an aggregate query in cases where the result of evaluating the term depends only one one or more of the GROUP BY expressions (and on no other inputs). (check-in: 5375a3ce56 user: dan tags: having-where-optimization) | |
| 18:02 | Improvements to opcode documentation in the bytecode engine. No changes to code. (check-in: e54c9f8db5 user: drh tags: trunk) | |
| 15:27 | Evaluate WHERE clause terms that reference only the index before evaluating terms that require the table, and thereby avoid seeking the table row if index terms are false. This is called the "push-down" optimization in the MySQL world, we are told. Do not confuse with WHERE-clause push-down. (check-in: d7bb79ed3a user: drh tags: trunk) | |
| 14:56 | Minor size and performance improvements to the push-down optimization. (Closed-Leaf check-in: 91dfb61a1a user: drh tags: pushdown-optimization) | |
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2017-04-26
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| 17:21 | Add new test file cachespill.test. (check-in: 2d0b64316d user: dan tags: trunk) | |
Changes
Changes to src/wherecode.c.
Added test/pushdown.test.