tech

higher TCP ICW – real world tests

by .pQd
this post inspired me to check how much performance can we gain by just upgrading to more recent kernel on the internet-facing proxy servers at work.

extracting single database from a [large] mysqldump

by .pQd
extracting the whole database: sed -n '/^-- Current Database: `databaseName`/,/^-- Current Database: `/p' /path/to/the/fill/dump.sql > output.sql single table: sed -n '/^CREATE TABLE `tableName`/,/^\-\- Table structure for table /p' /path/to/the/fill/dump.sql > output.sql [via this blog]

switching reverse proxy from apache2 to nginx

by .pQd
i’ve been planning for a while to move away from apache2 as a reverse proxy in front of java appservs and start using nginx. i had two reasons: nginx can handle much better large number of concurrent connections [something we can make use of if we start using long-poll/comet], nginx gives more control over buffering ... Read More

new sphinx, new connector/j headaches

by .pQd
sphinx 2.0.3 is out; and as new drama of getting mysql’s connector/j begins. i did not figure out [yet] any way of making both work using the latest 5.1.18 connector, but at least i’ve managed to convince one that i use now [ 5.1.15 ] to work with sphinx. what works: mysql-connector-java-5.1.13-bin.jar but.. only if ... Read More

excluding some mysql queries from the slow query log

by .pQd
i keep close eye on the mysql-slow.log log of queries that take more than 1s to execute. but at the same time i know about few house-keeping queries that are executed few times per day that by design take longer to execute [eg table checksums]. i don’t want those queries to ‘pollute’ the slow query ... Read More

java7, XMLEncoder problems

by .pQd
for the last few days i’ve been looking into java7… it surely seems faster. but also some of my old code broke when run under it.

ghettovcb hangs while removing the snapshot

by .pQd
i’ve upgraded few vmware esxi 4.1 servers with the latest patches and… obviously something got broken. i use ghettoVCB script to take weekly snapshots of the vms. scripts hanged last night on all servers.

ilo

by .pQd
i take care of one HP server with ILO remote access card. but recently i started having problems with using web applet to connect to it.

kindle 3g

by .pQd
few months ago i bought kindle 3g. below what’s good and what’s bad about it.

mysql 5.1 – turning on/off query logging on the fly

by .pQd
i dont run query logging – more to avoid running out of the disk space on /var/log than for the performance reasons. but from time to time it’s good to be able to turn logging on to see what’s going on. in 5.1 and later versions it’s possible without restarting the mysqld.

innodb_stats_sample_pages to save a day

by .pQd
i’ve run into nasty instability in mysql’s query execution plan joining few tables with 10s of millions of rows. mysql 5.1’s innodb_stats_sample_pages seem to solve the problem.