Oracle invents time machine - optimizer now faster than light.

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Tue, 23 Apr 2002 01:58:37 -0800
Message-ID: <F001.0044C2CB.20020423015837@fatcity.com>

Look carefully at the following (genuine) extract from a 9.0.1.3 trace file, and examine the TIM= entries:

PARSING IN CURSOR #2 len=210 dep=1 uid=0 oct=3 lid=0 tim=1019495629365212 hv=787810128 ad='6e0a278' select /*+ rule */ bucket_cnt, row_cnt, cache_cnt, null_cnt, timestamp#, sample_size, minimum, maximum, distcnt, lowval, hival, density, col#, spare1, spare2, avgcln from hist_head$ where obj#=:1 and intcol#=:2
END OF STMT
PARSE
#2:c=0,e=492,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=3,tim=1019495629365100

Note how Oracle has managed to finish parsing the statement 112 microseconds before it started.

Now that's how to pass a benchmark !

Jonathan Lewis
http://www.jlcomp.demon.co.uk

Author of:
Practical Oracle 8i: Building Efficient Databases

Next Seminar - Australia - July/August
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Author: Jonathan Lewis
  INET: jonathan_at_jlcomp.demon.co.uk

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