The Speed of memcached
peter.alberer at wu-wien.ac.at
Wed Oct 12 13:09:35 PDT 2005
hm, no i cannot set that option from tcl for the socket as far as i know
do you mean i should try to use it or not?
i have not seen that perl or phyton clients use TCP_NODELAY...
>If you rolled your own client, are you doing TCP_NODELAY? That tends to
>be the first thing to bite people.
>On Wed, 12 Oct 2005, Peter Alberer wrote:
>>i have created a simple tcl-based client api to memcached for use in the
>>aolserver webserver. after the completion of the client api, my first
>>that the memcached server is quite slow when saving values, compared to
>>my database (postgresql 8.0). i would like to mention, that i only open
>>the communication sockets once for all the
>>operations and cache it in the api.
>>i created a test-loop that saves 100 different keys (test1-100) with the
>>same value (value length is about 1000 characters) to 2 different
>>memcached servers (50 each),
>>rereads all of the values and deletes all of them afterwards. (no multi
>>get, just 100 single get commands)
>>Here are the results measured in ms:
>>Memcache SET: Processed 100 items in 4060 ms
>>Memcache GET: Processed 100 items in 438 ms
>>Memcache DELETE: Processed 100 items in 82 ms
>>The set command is quite slow, compared to the get and delete command.
>>are the numbers i am getting here reasonable? interestingly,
>>the VERY FIRST set command completes in 0-1 ms, but ALL of the
>>subsequent ones take 40-41ms. this is something i can even see when i
>>set keys via telnet. the first set command returns STORED immediately,
>>but after that a very small delay is visible for every set command.
>>changing the length of the value
>>does not affect the 40ms for storing the value, just the get operation
>>have others measured the performance of the different memcached operations?
>>i would be very glad to hear about your observations!
>>ps: the system where the memcached daemon is running is a power5-redhat
>>AS4 server. kernel=2.6.9-11.EL
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