Hi, One of our customers had a very bad issue while trying to reassign objects from user A to user B. He had a lot of them, and the backend got very hungry for memory. It finally all went down when the linux kernel decided to kill the backend (-9 of course).
I attach three shell scripts showing the issue. create.sh creates a database and two users. Then it imports a million Large Objects in this new database. There's no drop.sh as it is a simple "dropdb foodb". session1_monitor.sh will start logging memory usage in the server log file every second. So it needs v14, but our customer is in v11. While this script runs, you can start session2_reindex.sh. This script will only run a reassign from one user to another. Here is what I get in the server log file: $ grep "Grand total" 14.log LOG: Grand total: 15560832 bytes... LOG: Grand total: 68710528 bytes... LOG: Grand total: 119976064 bytes.. LOG: Grand total: 171626624 bytes... LOG: Grand total: 224211072 bytes... LOG: Grand total: 276615296 bytes... LOG: Grand total: 325611648 bytes... LOG: Grand total: 378196096 bytes... LOG: Grand total: 429838464 bytes... LOG: Grand total: 481104000 bytes... IOW, it's asking for at least 481MB to reassign 1 million empty LO. It strikes me as odd. FWIW, the biggest memory context is this one: LOG: level: 2; PortalContext: 479963904 total in 58590 blocks; 2662328 free (32567 chunks); 477301576 used: <unnamed> Memory is released at the end of the reassignment. So it's definitely not leaked forever, but only during the operation, which looks like a missing pfree (or something related). I've tried to find something like that in the code somewhere, but to no avail. I'm pretty sure I missed something, which is the reason for this email :) Thanks. Regards. PS : we've found a workaround to make it work for our customer (executing all the required ALTER LARGE OBJECT ... OWNER TO ...), but I'm still amazed by this weird behaviour. -- Guillaume.
create.sh
Description: application/shellscript
session2_reindex.sh
Description: application/shellscript
session1_monitor.sh
Description: application/shellscript
