> An SQLite user has brought to our attention a performance issue in SQLite
> that seems to be associated with malloc(). If you have insights or
> corroborating experience with this issue please let me know.
We recently had a malloc/free slowdown issue after
changing to VS2008 in combination with XP.
Not sure if it applies in your case but for us
this helps:
--
if( _get_sbh_threshold() < 512 )
{
_set_sbh_threshold(512);
}
---
I'm unable to run your sqlite3.exe: MSVCR100.dll no found.
Anyway, maybe the above helps.
KInd regards
Marcus
>
> SQLite supports a "zero-malloc option" (see
> http://www.sqlite.org/malloc.html#memsys5 for details) which uses its own
> internal memory allocator rather than system malloc(). Earlier today, we
> patched the command-line shell to allow the zero-malloc option to be
> turned
> on. If you do:
>
> sqlite3 DATABASE
>
> then the regular system memory allocator is used, but if you say:
>
> sqlite3 -heap 100M DATABASE
>
> then the MEMSYS5 memory allocator will be used with a pool of 100MB of
> memory to work with. (You can adjust the size of your memory pool for
> whatever you need.)
>
> There are win32 and win64 builds of this updated command-line shell
> compiled
> using vs2010 here:
>
> http://www.sqlite.org/draft/download.html
>
> For certain full-text search queries against a large database, we are
> seeing
> speeds which are 3x faster when using "-heap 300M" (the memsys5 memory
> allocator) versus omitting the -heap option and thus using system
> malloc().
> This is on windows7. Similar results are seen with both gcc and vs2010
> builds.
>
> If you have any large queries that you can run on windows using the
> command-line shell, I would appreciate you timing those queries using the
> new shells from the download page, both with "-heap 300M" and without it,
> and letting me know about any performance differences you see.
>
> I also observe that compiling for 64-bit using vs2010 (not an option with
> my
> ancient version 2.95.3 gcc cross-compiler) that the queries are an
> additional 2x faster. I was surprised at the dramatic performance
> increase
> in going from 32-bit to 64-bit. Is such a speed-up typical?
>
> The use of "-heap 300M" seems to not make any performance difference on
> Linux.
>
> Any insights into why this is, what we are doing wrong, or what we can do
> to
> improve the performance of malloc() on windows will be appreciated.
>
> --
> D. Richard Hipp
> d...@sqlite.org
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>
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