[tahoe-lafs-trac-stream] [tahoe-lafs] #1870: leasedb: performance regression

[tahoe-lafs]

#1870: leasedb: performance regression
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     Reporter:           |      Owner:  daira
  davidsarah             |     Status:  new
         Type:  defect   |  Milestone:  1.11.0
     Priority:  normal   |    Version:  1.9.2
    Component:  code-    |   Keywords:  leasedb performance regression
  storage                |  sqlite
   Resolution:           |
Launchpad Bug:           |
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Comment (by daira):

 Aha, I believe these are Statement Journal Files (section 2.5 of
 [http://www.sqlite.org/tempfiles.html]).

 What's confusing is that "A statement journal is only created for an
 UPDATE or INSERT statement that might change multiple rows of a database
 [...]". `INSERT OR REPLACE INTO` queries by definition never affect
 multiple rows. The `UPDATE` statement in comment:27 cannot update multiple
 rows because the `WHERE` clause specifies exact values for `storage_index`
 and `shnum`, which together form the primary key, although I can see why
 sqlite might not "know" that in advance.

-- 
Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/1870#comment:30>
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