memcached udp datagram size and noreply option support

Tomash Brechko tomash.brechko at
Sat May 3 16:11:26 UTC 2008

On Sat, May 03, 2008 at 08:25:35 -0700, Dongni Chen wrote:
> I am currently running memcached 1.2.4 and want to use "Set" with
> "noreply" option. But seems it doesn't support. Shall I move to
> 1.2.5 to get this feature?

Yes, noreply is supported starting with memcached 1.2.5.

> I am also use udp mode, and found out even for a data size that is
> about 1.9k, I am getting 2 datagrams. I used memcached -vv, and it
> says when in udp mode, the sendbuf is 268435456.

Maximum Transfer Unit (MTU) is still limited to some smaller value,
likely 1500 bytes.  Though it's possible to increase it up to 64KB,
doing so will likely have strong negative effect on your network.  In
other words, better to leave it as is, and deal with multiple packets,
or switch back to TCP.  If you are trying to save on TCP connection
establishing, it would be better to think about ways to cache and
reuse the connection.

   Tomash Brechko

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