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Overview
| Comment: | 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. |
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| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
6df18e949d3676290785143993513ea1 |
| User & Date: | drh 2015-06-02 18:09:18.284 |
| Original Comment: | 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. |
References
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2022-10-14
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| 19:30 | Fix a problem with using the push-down optimization on compound SELECTs where component SELECTs use different collation sequences. dbsqlfuzz 11516f050100243e5a845f5a2b48a90ed2efaf2e. This problem appears to go all the way back to the beginning of the push-down optimization in check-in 6df18e949d367629 in SQLite 3.8.11. (check-in: ed14863dd7 user: dan tags: trunk) | |
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2017-07-17
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| 19:37 | 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. This is a cherry-pick of [6df18e949d36] with bug fixes. (check-in: cd6ac07848 user: drh tags: branch-3.8.9) | |
| 19:07 | 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. Cherry-pick from [6df18e949d36]. Still need to backport bug fixes associated with that check-in. (check-in: 043d6ce8ad user: drh tags: push-down-backport) | |
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2017-04-29
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| 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) | |
Context
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2017-07-17
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| 19:07 | 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. Cherry-pick from [6df18e949d36]. Still need to backport bug fixes associated with that check-in. (check-in: 043d6ce8ad user: drh tags: push-down-backport) | |
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2015-06-02
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| 19:36 | Always check for cell overflow before returning a slot from the pageFindSlot routine in btree.c. (check-in: 9f035c45a4 user: drh tags: trunk) | |
| 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) | |
| 17:25 | Add test cases for type affinity rules. (check-in: 9678646d9a user: drh tags: trunk) | |
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2015-06-01
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| 20:28 | For FROM-clause subqueries that cannot be flattened, try to push WHERE clause terms of the outer query down into the subquery in order to help the subquery run faster and/or use less memory. (Closed-Leaf check-in: 297fae7551 user: drh tags: subquery-opt) | |
Changes
Changes to src/select.c.