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Re: Strange error message in logs

From: Brian Tingle <brian.tingle(at)not-real.ucop.edu>
Date: Wed Mar 26 2003 - 23:22:34 GMT
At 02:44 PM 3/19/2003 -0800, Bill Moseley wrote:
>On Wed, 19 Mar 2003, Brian Tingle wrote:
> > Just testing it out as a single user things look normal and work fine, but
> > when I crank up concurrent users, I get messages like these in the logs.
> >
> >
> > Warning: Failed to uncompress Property. zlib uncompress returned:
> > -5.  uncompressed size: 30578 buf_len: -4265104
> >
> > err: Ran out of memory (could not allocate 4294967169 more bytes)!
>
> > Anything to worry about?
>
>Probably.
>
>The zlib errors: -3 is Z_DATA_ERROR and -5 is Z_BUF_ERROR.
>
>Are you using Apache Bench?  And if so just changing -c causes the
>problem?

yes, using ab it never happens at -c1; but if I set -c10 and do a new 
search or clear CGI::Cache's cache it happens every time.  ~10 to 15 
messages, randomly flipping between the -3 error the -5 error and the 
memory error.

>I don't know why changing conncurent users would make a
>difference.

One of the error that pops up is
"err: Ran out of memory (could not allocate 4294967169 more bytes)!"
Is that coming from SWISH?

Could it be a memory thing? the index file is 27M * 10 requests coming in 
at once (all before CGI::Cache has cached anything).  The prop file is 9M 
-- I think it only has 2 properties in it.

Humm, it looks like when I do ab -n10 -c10 with a clear cache that only one 
of the first 10 queries really works.

with -n10 and -c10, when I look at the access log, I get something like
code    bytes   sec
200     29339   12
200     29339   0
200     29339   0
200     29339   0
200     29339   0
200     29339   0
200     29339   0
200     29339   0
200     29339   0
200     29339   0
200     8192    17
200     8192    17
200     8192    17
200     8192    17
200     8192    17
200     8192    18
200     8192    18
200     8192    19

Does the library try to lock the property file?

>Are you requesting the same data or by using more concurrent
>users are you just requesting different records.
Same search query.


>I'd suspect a potential problem with a single record than with the load,
>but that's just a guess at this point.  Can you reproduce that error if
>you use SWISH::API and search for "not notawordinyourdocs" and then loop
>through all the results and fetch all properties?

It happens with any query ... so I don't suspect an individual record.


>By the way, what kind of requests per second are you seeing with using the
>library?

I'm using CGI::Cache too, so its hard to say.





>--
>Bill Moseley moseley@hank.org

-- Brian Tingle
    Development Programmer, California Digital Library
    (510)987-0443
Received on Wed Mar 26 23:23:27 2003