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seen Jul 20 '10 at 4:44

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awarded  Popular Question
Jul
19
comment MySQL master-master-replication as master for master-slave-replication
Thanks for reply. Sure, this would be less to administrate, but we want to have very small administration expanse when one of the slave servers has to be removed or some new servers have to be added to the slave pool.
Jul
19
asked MySQL master-master-replication as master for master-slave-replication
Jul
14
comment MySQL problem with many concurrent connections
I'm using Debian Lenny. The following additional settings were made: echo 131072 > /proc/sys/net/nf_conntrack_max echo 131072 > /proc/sys/net/netfilter/nf_conntrack_max echo 3 > /proc/sys/net/netfilter/nf_conntrack_tcp_timeout_time_wait echo 1 > /proc/sys/net/ipv4/tcp_tw_recycle echo 1 > /proc/sys/net/ipv4/tcp_tw_reuse But remember, all interprocess communication is made via sockets, so these settings doesn't affect this.
Jul
14
comment MySQL problem with many concurrent connections
Thanks for your replies. For me it looks like it's a problem with concurrent thread creating by MySQL. Because when 1500 persistent connections are established no more error occurs and these connections can be used by 1500 scripts at one time, so I don't believe in a problem with parallel access to socket or a TCP problem. To sum up - ulimit=32768, max_connections=2000, php_fastcgi_children=1500 - execution of 1500 concurrent requests with non-persistent connections always fails with this "Resource temporarily unavailable" (only a small portion of request is handled) - when adding random delay
Jul
14
comment MySQL problem with many concurrent connections
I don't think so, because the problem is already the connection to MySQL and not a query. At this point it doesn't have to do something with InnoDB (IMHO).
Jul
14
awarded  Student
Jul
12
comment MySQL problem with many concurrent connections
I wrote, that the "resource temporarily unavailable" error occurs every time, already when using only some hundred non-persistent connections. Now, I've added usleep(rand(500000,1500000)); before mysql connect call in my php script, so that this script sleeps for a random time (0.5-1.5 seconds) before connecting to mysql. And tadaaa, the problem doesn't occur with non-persistent connection. So could it possibly be, that MySQL has a problem with massive concurrent thread creation?
Jul
12
asked MySQL problem with many concurrent connections