https://bugs.kde.org/show_bug.cgi?id=216895 Summary: Improve performance and reduce space with some sqlite3
pragma's
Product: digikam
Version: unspecified
Platform: Debian testing
OS/Version: Linux
Status: UNCONFIRMED
Severity: normal
Priority: NOR
Component: general
AssignedTo:
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ReportedBy:
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Version: 1.0.0beta6 (using KDE 4.3.2)
OS: Linux
Installed from: Debian testing/unstable Packages
You have an awesome program that I enjoy using. Just a couple of things you can
do to make it better. The default setup of sqlite uses a 1kb page size. This
can lead to a lot of wasted space in the large tuples that digikam uses.
Increasing the pagesize to 4kb reduces the total database size by a third. I
used 4kb because it matches the normal intel page size and larger page sizes
have marginal benefit (<1% space savings). I also suspect this page size comes
with some performance benefits.
For existing databases (and recent versions of sqlite3):
'pragma page_size = 4096 ; vacuum;'
When creating a new database:
'pragma page_size = 4096;' before the first table.
Also, in order to run in limited environments, sqlite only lets itself use a
default of at most of 2000 pages worth of data for caching or internal sorts. I
propose increasing this to 8k-16k pages (32-64mb). Modern machines have a lot
of RAM. I've not benchmarked if there is any speed improvement, but I cannot
see how giving sqlite a few more megabytes of memory can hurt.
Can be run on any existing or new database:
'pragma default_cache_size=16000;'
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