[Xapian-discuss] Unexpected slowness

Olly Betts olly at survex.com
Wed Feb 7 02:22:21 GMT 2007


On Tue, Feb 06, 2007 at 05:40:12PM +0200, Daniel Andersson wrote:
> faster as in faster cpu, faster disks and faster memory
> but it only has 1 gb of ram
> it's running on megaraid with scsi-disks. from bonnie++:

It does seem odd that it's slower then.  I can't think of anything
obvious that would explain this.

Are you testing with the same databases, just copied across (rather than
rebuilt)?

Is the live machine the same architecture and running the same OS
version and compiler version as the Linux dev box?

> have tried searches on multiple occasions, both when the machine was  
> under load and when it was not. still slow..

One thought - do search times improve if you do more searches?  When
nothing is cached, a search will be slower as everything needed has
to be read from disk.  Subsequent searches will need many of the same
blocks so the first few searches will typically each be faster than the
one before.

If it's not that effect, then I guess you'll have to try eliminating
possibilities.  For example, if you run a query with the "quest"
utility (in xapian-core/examples) does that show the same slow
behaviour as when PHP and Apache are involved?

> $ ls -l sub_index_0/
> total 1750116
> -rw-r--r--    1 tt       users          10 Jan 23 15:10 meta

That's a quartz database (flint databases have a small file called
"iamflint" instead of a small file called "meta").

Cheers,
    Olly



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