Timeline for How do redundant indexes impact query performance?
Current License: CC BY-SA 3.0
6 events
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| Dec 1, 2011 at 17:11 | comment | added | Remus Rusanu | @JNK: Yes, it will, I don't argue that. I'm saying that IX_1 and IX_2 are not redundant, as in the OP. They are two different indices with different role/purpose. | |
| Dec 1, 2011 at 16:08 | comment | added | JNK |
Specific example: IX_1 ON (id, lastname, firstname); IX_2 ON (id). IX_1 contains everything in IX_2, but if all you wanted to filter on was id would IX_2 not be quicker?
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| Dec 1, 2011 at 16:04 | comment | added | Remus Rusanu | @JNK: I would argue that in your example the two indices are not redundant. | |
| Dec 1, 2011 at 14:17 | comment | added | JNK | Can't there be a benefit to using a narrower index as well. As in a scenario where I have a wide covering index, and a narrow index on just one of the key fields - if the table is large enough would it not be quicker to use the narrower index on queries that only need that specific key? | |
| Dec 1, 2011 at 5:23 | vote | accept | Yaqub Ahmad | ||
| Dec 1, 2011 at 4:53 | history | answered | Remus Rusanu | CC BY-SA 3.0 |