On Wed, Nov 29, 2023 at 4:36 PM Abdul Qoyyuum <aqoyyuum@xxxxxxxxxxxxxxxxx> wrote:
Hi all,Knowing that it's a data corruption issue, the only way to fix this is to vacuum and reindex the database. What was suggested was the following:SET zero_damaged_pages = 0; # This is so that we can have the application to continue to runVACUUM FULL VERBOSE ANALYSE; # Do a full vacuum and analyse the problem if possible.REINDEX DATABASE "core"; # Then do a reindex and clean it up.
So first, to clear up some confusion on my part here:
This procedure doesn't make a lot of sense to me. But did it clear up the issue?
In any of these cases, it is extremely important to diagnose the system properly. If you have a fault in your storage device or RAID controller, for example, you are asking for more corruption and data loss later.
At first I thought maybe you mistyped something and then realized there were a few issues with the process so it actually didn't make sense.
First, zero_damaged_pages defaults to 0, and I can think of no reason to set it explicitly.
Secondly, a vacuum full has to reindex, so there is no reason to do a reindex following. Your whole procedure is limited to a vacuum full, when a reindex is the only part that could affect this. If it did work, reindexing is the only part that would have been helpful.
On to the question of what to do next....
We're on Postgresql 12. This has worked before it happened (almost exactly a year ago) and I think this needs a more permanent solution. I've looked at routine vacuuming and checked the autovacuum is set to on and the following configurations:core=> select name, setting from pg_settings where name like 'autovacuum%';
name | setting
-------------------------------------+-----------
autovacuum | on
autovacuum_analyze_scale_factor | 0.1
autovacuum_analyze_threshold | 50
autovacuum_freeze_max_age | 200000000
autovacuum_max_workers | 3
autovacuum_multixact_freeze_max_age | 400000000
autovacuum_naptime | 60
autovacuum_vacuum_cost_delay | 2
autovacuum_vacuum_cost_limit | -1
autovacuum_vacuum_scale_factor | 0.2
autovacuum_vacuum_threshold | 50
autovacuum_work_mem | -1
(12 rows)Can anyone advise if there's anything else we can do? We have no clue what causes the invalid page block and we are running a High Availability cluster set up but we are hoping that there may be a way to mitigate it.
If this is a server you run, the first things I would check are:
1. Is there a good-quality UPS that the server is plugged into? Are the batteries in good working order?
1. Is there a good-quality UPS that the server is plugged into? Are the batteries in good working order?
2. Is the server somewhere that may be sitting in a pocket of hot air?
Once you have ruled these out, the next things to check are CPU, memory, and storage health. Unfortunately checking these is harder but you can check SMART indications, and other diagnostic indicators.
Once you have ruled these out, the next things to check are CPU, memory, and storage health. Unfortunately checking these is harder but you can check SMART indications, and other diagnostic indicators.
However, once these errors start happening, you are in danger territory and need to find out why (and correct the underlying problem) before you get data loss.
Best Wishes,
Chris Travers
Efficito: Hosted Accounting and ERP. Robust and Flexible. No vendor lock-in.
