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From: | graydon hoare |
Subject: | [Monotone-devel] Re: CVS sync works (for me) |
Date: | Mon, 21 Feb 2005 13:58:44 -0500 |
User-agent: | Mozilla Thunderbird 1.0 (X11/20041206) |
Nathaniel Smith wrote:
If sqlite is like other rdbms's, I'd think that we already have indices on {manifest,file}_deltas.id, because usually unique constraints generate implicit indicies. Could be wrong, though.
yes, all 'unique' constraints generate indices in sqlite, as do all 'primary key' modifiers.
still, I think the 'unique' constraints -- in cases where they're a unique combination of multiple fields -- may not result in optimal index performance. for example if we request "all the certs on revision X" a lot, it might go slower than necessary since it needs to check that sub-index position within each of the K cert names. afaik the sqlite query planner isn't very clever, so in some cases I'm sure it just reverts to linear scan. feel free to experiment.
-graydon
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