lucene-java-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Dinh <pcd...@gmail.com>
Subject Why Lucene takes longer time for the first query and less for subsequent ones
Date Tue, 17 Nov 2009 17:39:14 GMT
Hi all,

I made a list of 4 simple, singe term queries and do 4 searches via Lucene
and find that if the term is used for search in the first time, Lucene takes
quite a bit time to handle it.

- Query A
00:27:28,781  INFO LuceneSearchService:151 - Internal search took
328.21463ms
00:27:28,781  INFO SearchController:86 - Page rendered in 338.29553ms

- Query B
00:27:39,171  INFO LuceneSearchService:151 - Internal search took
480.30908ms
00:27:39,187  INFO SearchController:86 - Page rendered in 493.07327ms

- Query C
00:27:46,765  INFO LuceneSearchService:151 - Internal search took
189.33635ms
00:27:46,765  INFO SearchController:86 - Page rendered in 195.43823ms

- Query D
00:28:00,312  INFO LuceneSearchService:151 - Internal search took 330.3596ms
00:28:00,328  INFO SearchController:86 - Page rendered in 347.34747ms


It looks no good at the first glance because I have only 500 000 indexed
documents. However, when I searched them again I found that Lucene run much
faster.

- Query A
00:28:04,046  INFO LuceneSearchService:151 - Internal search took 3.90301ms
00:28:04,062  INFO SearchController:86 - Page rendered in 15.694173ms

- Query C
00:28:15,390  INFO LuceneSearchService:151 - Internal search took 1.425879ms
00:28:15,390  INFO SearchController:86 - Page rendered in 7.946541ms

- Query D
00:28:26,031  INFO LuceneSearchService:151 - Internal search took 1.849956ms
00:28:26,046  INFO SearchController:86 - Page rendered in 12.023037ms

- Query B
00:28:31,609  INFO LuceneSearchService:151 - Internal search took 1.668648ms
00:28:31,625  INFO SearchController:86 - Page rendered in 15.57237ms

Why does it happens? Does it mean that Lucene has an internal cache engine,
just like MySQL query result cache or Oracle query execution plan cache?

Thanks

Dinh

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message