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15 check-ins using file src/select.c version 3c78ea0e70
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2022-08-09
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| 20:22 | Fix a rounding error caused by scalar->logarithm->scalar conversion when using stat4 data to estimate some range scans. (check-in: 68d86f2b20 user: drh tags: branch-3.28) | |
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2020-10-22
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| 18:58 | Minor tweaks to query planning weights so that when STAT4 is enabled and functioning, a full table scan is more likely to be selected if that seems like the fastest solution. Only do this when STAT4 info is available because an error has a large potential downside. (check-in: 263293f1e6 user: drh tags: branch-3.28) | |
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2020-10-02
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| 13:57 | Import further corner-case fixes for the in-scan-vs-index or OP_SeekScan optimization from trunk. (check-in: c144d6404f user: drh tags: branch-3.28) | |
| 12:11 | For the OP_SeekScan optimization, the OP_IdxGT does not necessarily come right after the OP_SeekGE. So use the P2 operand of OP_SeekScan to point to the first instruction after OP_IdxGT. Problem found by dbsqlfuzz. (check-in: ec37744c6e user: drh tags: branch-3.28) | |
| 02:07 | Disable the OP_SeekScan opcode of the in-scan-vs-index optimization when in PRAGMA reverse_unordered_selects mode, as the OP_SeekScan only works with forwards scans. Thanks to OSSFuzz for pointing out the problem to us. (check-in: 9a1cdf7e9c user: drh tags: branch-3.28) | |
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2020-09-30
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| 18:22 | Improved query optimization for multi-column indexes where the second or later columns are constrained by an IN operator and the earlier index columns limit the search to a small number of rows. Use the new OP_SeekScan opcode which does scanning of the relevant range of the index but gives up and falls back to doing a seek if the number of rows scanned grows to large, in order to guard against pathological cases where the estimated number of rows to be scanned is far too small. (check-in: f07ac3fb38 user: drh tags: branch-3.28) | |
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2020-09-01
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| 02:02 | Improvements to the IN-early-out optimization so that it works more efficiently when there are two or more indexed IN clauses on a single table. (check-in: 49b7631e86 user: drh tags: branch-3.28) | |
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2020-08-31
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| 19:19 | An attempt to improve the performance of the IN-early-out optimization (see check-in [09fffbdf9f2f6ce3]) by avoiding unnecessary calls to the b-tree search algorithm in OP_IfNoHope when the index key is at hand and the same answer can be obtained by doing a quick key comparison. Update: Experiment did not work out. (Closed-Leaf check-in: 8301da31d0 user: drh tags: branch-3.28-in-early-out-fail) | |
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2020-08-17
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| 21:03 | When doing an UPDATE or DELETE using a multi-column index where only a few of the earlier columns of the index are useful for the index lookup, postpone doing the main table seek until after all WHERE clause constraints have been evaluated, in case those constraints can be covered by unused later terms of the index, thus avoiding unnecessary main table seeks. (check-in: 0ecda43371 user: dan tags: branch-3.28) | |
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2020-05-06
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| 18:46 | Provide the SQLITE_DEFAULT_LEGACY_ALTER_TABLE compile-time option. (check-in: b2325a6e1c user: drh tags: branch-3.28) | |
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2020-01-17
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| 15:33 | More restrictions on changes to shadow tables when in defensive mode. (check-in: b302b260ca user: drh tags: branch-3.28) | |
| 15:24 | Validate the type, name, and tbl_name fields of the sqlite_master table when loading the schema, unless writable_schema is engaged. (check-in: 3d13fbf248 user: drh tags: branch-3.28) | |
| 14:56 | Do not allow shadow tables to be dropped in defensive mode. (check-in: ad1f760f16 user: drh tags: branch-3.28) | |
| 14:30 | Import the 3.31.0-beta FTS3/4 code directly into the 3.28 branch, thus providing 3.28 with all the latest 3.31 fixes. FTS3 has not been enhanced to use any core functionality that was not already available in 3.23, so no modifications were made to FTS3 sources for this import. (check-in: be4269c624 user: drh tags: branch-3.28) | |
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2019-07-18
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| 20:55 | Fix a problem where self-joins on views that are aggregate queries may return the wrong result. Cherrypick of [74ef97bf51dd531a]. (check-in: 2f0a564f6e user: mistachkin tags: branch-3.28) | |