On 7/22/2011 8:23 AM, Pierre GOSSE wrote:
I've read that in a thread title " Weird optimize performance degradation", where Erick Erickson
states that "Older versions of Lucene would search faster on an optimized index, but this is no longer
necessary.", and more recently in a thread you initiated a month ago "Question about
optimization".
I'll also be very interested if anyone had a more precise idea/datas of
benefits and tradeoff of optimize vs merge ...
My most recent testing has been with Solr 3.2.0. I have noticed some
speedup after optimizing an index, but the gain is not
earth-shattering. My index consists of 7 shards. One of them is small,
and receives all new documents every two minutes. The others are large,
and aside from deletes, are mostly static. Once a day, the oldest data
is distributed from the small shard to its proper place in the other six
shards.
The small shard is optimized once an hour, and usually takes less than a
minute. I optimize one large shard every day, so each one gets
optimized once every six days. That optimize takes 10-15 minutes. The
only reason that I optimize is to remove deleted documents, whatever
speedup I get is just icing on the cake. Deleted documents take up
space and continue to influence the relevance scoring of queries, so I
want to remove them.
Thanks,
Shawn
