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fixed slow query on normalized table; still 10x slower than current .map files

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Joey Hess 2014-03-13 09:38:20 -04:00
parent 66b8b9c094
commit 3e86d35e84
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7
doc/design/caching_database.mdwn
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@ -67,6 +67,7 @@ CachedKey
AssociatedFiles AssociatedFiles
keyId CachedKeyId Eq keyId CachedKeyId Eq
associatedFile FilePath associatedFile FilePath
KeyIdIndex keyId associatedFile
deriving Show deriving Show
CachedMetaField CachedMetaField
@ -86,6 +87,12 @@ LastFscked
With this, running 1000 joins to get the associated files of 1000 With this, running 1000 joins to get the associated files of 1000
Keys took 5.6s with warm cache. (When done in the same `runSqlite` call.) Ouch! Keys took 5.6s with warm cache. (When done in the same `runSqlite` call.) Ouch!
Update: This performance was fixed by adding `KeyIdOutdex keyId associatedFile`,
which adds a uniqueness constraint on the tuple of key and associatedFile.
With this, 1000 queries takes 0.406s. Note that persistent is probably not
actually doing a join at the SQL level, so this could be sped up using
eg, esquelito.
Compare the above with 1000 calls to `associatedFiles`, which is approximately Compare the above with 1000 calls to `associatedFiles`, which is approximately
as fast as just opening and reading 1000 files, so will take well under as fast as just opening and reading 1000 files, so will take well under
0.05s with a **cold** cache. 0.05s with a **cold** cache.