Performance before and after optimization

Ruby Apps Ferret
1

I have an index with a few hundred thousand records. The index is
generally very fast, with sub 100ms responses. However if I start
adding records, it gets extremely slow, up to over 2 seconds per
query. This is true even if I am not currently indexing until I
optimize the
index.

In order to work around this, I index in bulk and immediately
optimize. This is not ideal for the performance of my site.

Unfortunately, contrary to what Dave Balmain seems to say here:
OSDIR ,
the index seems to be locked for reading during optimization.

So I have two questions:

  1. Why does the performance degrade so badly after adding just a few
    records, unless I optimize the index? Can I avoid this?

  2. Can I keep a second index so that it doesn’t get locked during
    optimization and then switch to the optimized index? Perhaps the index
    is not really locked and it is just using all the CPU? (I am using a
    single CPU server)?

Thanks for any help.

-Alex

2

On Sat, Nov 03, 2007 at 08:49:17PM +0800, Alex Neth wrote:
[…]

  1. Can I keep a second index so that it doesn’t get locked during
    optimization and then switch to the optimized index? Perhaps the index
    is not really locked and it is just using all the CPU? (I am using a
    single CPU server)?

If you’re already indexing in batches, keeping a second read-only index
for
searching is a good idea. rsync is useful to keep the search-index up to
date in this case.

To check if CPU usage is a problem, try lowering the optimizing process’
priority and see how it goes.

Jens

–
Jens Krämer
http://www.jkraemer.net/ - Blog
http://www.omdb.org/ - The new free film database