Subversion And The Entropy Pool

I ran into an interesting little subversion problem earlier. I was trying to commit a change, and the commit just seemed to hang indefinitely. I couldn’t sent an interrupt, and eventually resorted to killing the process. I tried all sorts of command line options in case there was an authentication problem - with no luck. I then thought I had made a mistake when switching my working copy to a different branch. I checked the logs on the server to find nothing pertinent; it seemed as though svn didn’t get as far as taking to the server. At a loss, I thought there was nothing for it but to run the command with strace. Bingo!

Fixing MySQL Multi-Master Replication

I’ve had some exposure to database replication through PostgreSQL/Slony. I’m reasonably familiar with master/slave replication but in the last few days I’ve had to get my hands dirty and grok multi-master replication with MySQL, specifically with two MySQL servers in master<->master mode. Although conceptually it’s not a significant leap from simple master/slave replication the added layer of replication in both directions made my brain melt a little bit at first. Now that I’ve got my head around as much as I need to, I’m writing this as a gentle reminder should replication screw up again!

Display PostgreSQL Query Results Vertically

Those who are familiar with MySQL may be used to terminating a query with \G to have the client output the query results vertically with each column/value pair a line at a time. There is in a equivalent in PostgreSQL too. The psql client uses \x to toggle vertical output, and \g to send the current buffer to the server for processing. To get the same effect in psql as \G in MySQL, just end your query with \x\g\x.