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Diffstat (limited to 'src/wherecode.c')
| -rw-r--r-- | src/wherecode.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/wherecode.c b/src/wherecode.c index 47ce36ce3..1f9c84f00 100644 --- a/src/wherecode.c +++ b/src/wherecode.c @@ -2474,6 +2474,12 @@ Bitmask sqlite3WhereCodeOneLoopStart( ** iLoop==3: Code all remaining expressions. ** ** An effort is made to skip unnecessary iterations of the loop. + ** + ** This optimization of causing simple query restrictions to occur before + ** more complex one is call the "push-down" optimization in MySQL. Here + ** in SQLite, the name is "MySQL push-down", since there is also another + ** totally unrelated optimization called "WHERE-clause push-down". + ** Sometimes the qualifier is omitted, resulting in an ambiguity, so beware. */ iLoop = (pIdx ? 1 : 2); do{ |