By "cold" do you mean immediately following a server restart?  Is each "cold" 
run a new Java process?  If so, you probably have some class-loader activity in 
your measurement.  A fair bit of the difference is probably an authentication 
round-trip.  Might also be some penalty for DNS resolution.  Just a few 
thoughts.

Can you provide some more information and/or source code to clarify how you're 
running the test?

What OS/JDK versions are you running?  Are client and server on the same 
machine?

Sam Neth
Lead Engineer
MarkLogic Corporation

On Apr 14, 2011, at 12:52 PM, Mike Sokolov wrote:

I'm working on optimizing some queries on one of our MarkLogic sites
using cq's profiling feature and also looking at query times in our
logs, and they seem oddly out of sync.

The times in our logs are based on wrapping calls to XCC
Session.submitRequest() between calls to Java
System.currentTimeMillis(), so presumably they include some network time
and serialization/deserialization that may be different from what's
shown in cq.

However, the difference is much larger for cold queries (first time run)
then it is for warmed queries, which seems odd since you would expect
that kind of difference (packaging and transmission) to be the same for
warm and cold queries.

A typical set of numbers might be:

cold, cq: 110 ms
warm, cq 10 ms
cold, xcc: 440 ms
warm, xcc: 14 ms

This result is consistent across many queries: it's the rule, so far as
I can tell.

We're using a slightly older XCC (version 4.1.3, I think, and the server
version is 4.1.6). I do plan to upgrade, but this was so odd that I
wanted to make sure I wasn't overlooking something known that could
cause this kind of discrepancy.  Any ideas?

--
Michael Sokolov
Engineering Director
www.ifactory.com<http://www.ifactory.com>

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