Re: Understanding WAL - large amount of activity from removing data

2022-11-21 Thread Andres Freund
Hi, On 2022-11-20 19:02:12 -0700, David G. Johnston wrote: > Both of these are written to the WAL, and a record is always written > to the WAL as a self-contained unit, so the old record is full sized > in the newly written WAL. That's not really true. Normally the update record just logs the

Re: Understanding WAL - large amount of activity from removing data

2022-11-20 Thread David G. Johnston
On Sun, Nov 20, 2022 at 6:24 PM Isaac Morland wrote: > What I'm finding is that the UPDATE is taking over an hour for 5000 > records, and tons of WAL is being generated, several files per minute. > Selecting the non-PDF columns from the entire table takes a few > milliseconds, and the only thing

Understanding WAL - large amount of activity from removing data

2022-11-20 Thread Isaac Morland
I'm encountering some surprising (to me) behaviour related to WAL, and I'm wondering if anybody can point me at an article that might help me understand what is happening, or give a brief explanation. I'm trying to make a slimmed down version of my database for testing purposes. As part of this,