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From Erick Erickson <>
Subject Re: NRT and commit behavior
Date Thu, 01 Sep 2011 12:38:07 GMT
Hmm, I'm guessing a bit here, but using an invalid query
doesn't sound very safe, but I suppose it *might* be OK.

What does "invalid" mean? Syntax error? not safe.

search that returns 0 results? I don't know, but I'd guess
that filling your caches, which is the point of warming
queries, might be short circuited if the query returns
0 results but I don't know for sure.

But the fact that "invalid queries return quicker" does not
inspire confidence since the *point* of warming queries
is to spend the time up front so your users don't have to

So here's a test. Comment out your warming queries.
Restart your server and fire the warming query from
the browser with&debugQuery=on and look at the
QTime parameter.

Now fire the same form of the query (as in the same
sort, facet, grouping, etc, but presumably a valid
term). See the QTime.

Now fire the same form of the query with a *different*
value in the query. That is, it should search on different
terms but with the same sort, facet, etc. to avoid
getting your data straight from the queryResultCache.

My guess is that the last query will return much more quickly
than the second query. Which would indicate that the first
form isn't doing you any good.

But a test is worth a thousand opinions.


On Wed, Aug 31, 2011 at 11:04 AM, Tirthankar Chatterjee
<> wrote:
> Also noticed that "waitSearcher" parameter value is not  honored inside commit. It is
always defaulted to true which makes it slow during indexing.
> What we are trying to do is use an invalid query (which wont return any results) as a
warming query. This way the commit returns faster. Are we doing something wrong here?
> Thanks,
> Tirthankar
> -----Original Message-----
> From: Jonathan Rochkind []
> Sent: Monday, July 18, 2011 11:38 AM
> To:;
> Subject: Re: NRT and commit behavior
> In practice, in my experience at least, a very 'expensive' commit can still slow down
searches significantly, I think just due to CPU (or
> i/o?) starvation. Not sure anything can be done about that.  That's my experience in
Solr 1.4.1, but since searches have always been async with commits, it probably is the same
situation even in more recent versions, I'd guess.
> On 7/18/2011 11:07 AM, Yonik Seeley wrote:
>> On Mon, Jul 18, 2011 at 10:53 AM, Nicholas Chase<>  wrote:
>>> Very glad to hear that NRT is finally here!  But my question is this:
>>> will things still come to a standstill during a commit?
>> New updates can now proceed in parallel with a commit, and searches
>> have always been completely asynchronous w.r.t. commits.
>> -Yonik
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