The easiest thing to do is to run your php script via php-cli and strace
the php-cli process as it runs, you'll then figure out what time is
being spent on.
K J wrote:
The default connection timeout in pecl/memcache is 1 second, and when
using Memcache::addServer() the connection isn't established until the
first command is sent (ie. the "get" in your example). Perhaps you
have
added several servers, one of which is unreachable, and thus the
client
will stall 1 second before flagging that server as down and trying the
next one. If you're using persistent connections, that server will
still
be flagged as down on subsequent requests and will be skipped
immediately.
Or as Marc said, the client might indeed be waiting for a DNS
response..
I've used IPs, not hostnames, so unless memcache is doing a reverse
DNS lookup, I doubt that's the cause.
As for servers, I do have 2 memcache servers, but they are both up and
running.
Any other ideas, or ways I can go about hunting this thing down?
On 10/27/07, *Mikael Johansson* <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>> wrote:
Hi,
The default connection timeout in pecl/memcache is 1 second, and when
using Memcache::addServer() the connection isn't established until
the
first command is sent (ie. the "get" in your example). Perhaps you
have
added several servers, one of which is unreachable, and thus the
client
will stall 1 second before flagging that server as down and trying
the
next one. If you're using persistent connections, that server will
still
be flagged as down on subsequent requests and will be skipped
immediately.
Or as Marc said, the client might indeed be waiting for a DNS
response..
//Mikael
K J wrote:
> The slowdown is almost certainly in your client library. The
server, on
> our systems, takes about 1.5 milliseconds to start up, and a
> fraction of
> a millisecond to answer the first request. But your client
might be
> doing a lot of work the first time it executes. You didn't
say what your
> client language and environment is, so it's kind of hard to
even take a
> useful guess.
>
>
> The app is running on PHP and is using the PHP memcache library:
> http://cn2.php.net/manual/en/ref.memcache.php
>
> I record the time it takes to render a page, and every page ends up
> taking 1 second or so. Most of that 1 second is due to the very
first
> memcache get request. It happens at every page that uses
memcache. The
> only time this problem goes away is when I run a load testing
tool and
> start having multiple users hit the system constantly.
>
>
>
>
> On 10/27/07, *Steven Grimm* <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>
> <mailto: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>>> wrote:
>
> K J wrote:
> > So it's normal to have Memcache's response time be 1
second, if the
> > system is relatively idle? This happens when I'm
basically the only
> > user on the system, logging in, checking pages, etc.
>
> The slowdown is almost certainly in your client library. The
server, on
> our systems, takes about 1.5 milliseconds to start up, and a
fraction of
> a millisecond to answer the first request. But your client
might be
> doing a lot of work the first time it executes. You didn't
say what your
> client language and environment is, so it's kind of hard to
even take a
> useful guess.
>
> -Steve
>
>
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