Comments for Flying Bug

Comment on Symfony and Godaddy by Hang

Hang — Wed, 03 Mar 2010 05:17:17 +0000

Geeze … I’ve been away from symfony for quite some time.

Seriously, I don’t know the answer, and I don’t have time to dig into it now, wish you luck to get answer from somewhere else.

Comment on Symfony and Godaddy by Tiago Carvalho

Tiago Carvalho — Wed, 03 Mar 2010 02:05:45 +0000

Hi!

Thanks a lot for your tips! It all worked for me except for one thing.. I can access my site through the dev interface (both frontend_dev.php and backend_dev.php). But I can’t access it via the production environment… It just keeps returning me a non-symfony “404 page not found” page… I guess it must have to be something in .htaccess.. A

Any ideas?

Thanks in advance!

Comment on Cassandra’s read performance by Hang

Hang — Sun, 31 Jan 2010 22:49:06 +0000

I take my works back – “login” is not a just key-value lookup, as it needs to go through buddies in the buddy list, and do table look up again, I’m using same application logic for both Cassandra and MySQL.

However, denormalization is a problem for this case, if I store buddy’s information within a user record, it means every time a user changes his/her profile, I have to go though all users that having him/her in buddy list to update, this will be something like twitter – I may trigger hundreds or even thousands of updates for a simple change.

Maybe this kind of application may not be suitable for Cassandra, those pure key-value pair data stores may do better.

Comment on Cassandra’s read performance by Hang

Hang — Sun, 31 Jan 2010 22:42:31 +0000

I will try out those configurations.

I don’t think denormalization is a concern here, as “login” application is just a key-value lookup, that is, looking for the user based on user name, verify password, that’s all.

Comment on Cassandra’s read performance by Jonathan Ellis

Jonathan Ellis — Fri, 29 Jan 2010 22:23:18 +0000

With 0.5 you should increase KeysCachedFraction to 0.2 or even more, depending on how many rows you have and how “hot” they are. The default of 0.01 is too conservative for many cases.

Also, try to denormalize as much as possible; Cassandra will not perform well if you just try to port a MySQL schema to it straight across.

Let us know on irc or the mailing list if you have any other questions!

Comment on Cassandra’s read performance by Flying Bug » Playing with the performance again

Flying Bug » Playing with the performance again — Thu, 21 Jan 2010 20:55:54 +0000

[...] believe previous test was using a data set that is too small – it has only 100K records and volume is about 120M [...]

Comment on Cassandra’s read performance by Hang

Hang — Wed, 20 Jan 2010 07:54:11 +0000

I think I need to check out CouchDB and/or MongoDB for online feature (replication and cluster are two major concerns), and will check if Cassandara can work as offline processing (log processing?).

Comment on Cassandra’s read performance by Hang

Hang — Wed, 20 Jan 2010 07:29:53 +0000

Same box running un-tuned mysql give me 10X throughput for login operation – 128 concurrent clients, overall QPS is about 2,800, latency is about 45ms.

It seems Cassandra is more like a solution for scalability, whenever data volume is not that big, mysql would be a better solution in term of speed.

Comment on Cassandra’s read performance by Hang

Hang — Tue, 19 Jan 2010 22:41:36 +0000

Did a quick test and it seems 2-nodes (ReplicationFactor=2) cluster is getting 10% performance lost compare with single node cluster, and it seems the performance lost is growing along with number of concurrent clients growth.

Now, weird thing – with ReplicationFactor=1, the performance went down another 8~10%. It seems I have to read codes to see how Cassandra deals with multiple replica as the behavior looks inconsistent.

Comment on Adding new nodes to Cassandra cluster by Hang

Hang — Tue, 19 Jan 2010 05:23:18 +0000

BTW, it seems things like Cassandra are trying to solve the problem of data growth, it is not pure high performance oriented solution, so in real world I may still need things like memcached.