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

[tahoe-lafs]

#1870: leasedb: performance regression
-------------------------+-------------------------------------------------
     Reporter:           |      Owner:  daira
  davidsarah             |     Status:  assigned
         Type:  defect   |  Milestone:  1.11.0
     Priority:  normal   |    Version:  1.9.2
    Component:  code-    |   Keywords:  leasedb performance regression
  storage                |  sqlite
   Resolution:           |
Launchpad Bug:           |
-------------------------+-------------------------------------------------
Description changed by daira:

Old description:

> The [https://github.com/davidsarah/tahoe-lafs/commits/1818-leasedb
> 1818-leasedb] branch has a performance regression that shows up when
> running the test suite -- in fact, the test suite is not able to pass at
> the moment purely due to timeouts.
>
> Since the regression does ''not'' show up when using {{{make tmpfstest}}}
> (which uses a memory-based tmpfs filesystem rather than disk), my
> tentative conclusion is that it is due to the latency of leasedb database
> syncs. There are currently many redundant syncs due to every SQL
> query/update being in a separate transaction, and due to there being more
> SQL queries and updates than necessary per storage API request. We could
> also use a more relaxed consistency mode, if that is safe.

New description:

 The [https://github.com/davidsarah/tahoe-lafs/commits/1818-leasedb
 1818-leasedb] branch has a performance regression that shows up when
 running the test suite ~~-- in fact, the test suite is not able to pass at
 the moment purely due to timeouts~~.

 Since the regression does ''not'' show up when using {{{make tmpfstest}}}
 (which uses a memory-based tmpfs filesystem rather than disk), my
 tentative conclusion is that it is due to the latency of leasedb database
 syncs. There are currently many redundant syncs due to every SQL
 query/update being in a separate transaction, and due to there being more
 SQL queries and updates than necessary per storage API request. We could
 also use a more relaxed consistency mode, if that is safe.

--

-- 
Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/1870#comment:14>
tahoe-lafs <https://tahoe-lafs.org>
secure decentralized storage