On Apr 14, 2010, at 7:10 AM, Heikki Linnakangas wrote:
> Rusty Conover wrote: >> It seems like this is a race condition cause by the system catalog cache not >> being locked properly. I've included a perl script below that causes the >> crash on my box consistently. >> >> The script forks two different types of processes: >> >> #1 - begin transaction, create a few temp tables and analyze them in a >> transaction, commit (running in database foobar_1) >> #2 - begin transaction, truncate table, insert records into table from >> select in a transaction, commit (running in database foobar_2) >> >> I setup the process to have 10 instances of task #1 and 1 instance of task >> #2. >> >> Running this script causes the crash of postgres within seconds on my box. > > Thanks, that script crashes on my laptop too, with assertions enabled. > > According to the comments above RelationClearRelation(), if it's called > with 'rebuild=true', the caller should hold a lock on the relation, i.e > refcnt > 0. That's not the case in RelationFlushRelation() when it > rebuilds a new relcache entry. > > Attached patch should fix that, by incrementing the reference count > while the entry is rebuilt. It also adds an Assertion in > RelationClearRelation() to check that the refcnt is indeed > 0. > Comments? Hi Heikki, This patch allows my machine to run the script without crashing, so its working for me as well. Many thanks, Rusty -- Rusty Conover rcono...@infogears.com InfoGears Inc / GearBuyer.com / FootwearBuyer.com http://www.infogears.com http://www.gearbuyer.com http://www.footwearbuyer.com
