I've been hacking a bit in neighboring thread. And come across one interesting thing. There was a patch on this CF on enabling checksums for SLRU. The thing is CLOG is not protected with checksums right now. But the bad thing about it is that there's no reserved place for checksums in SLRU. And this conversion from page without checksum to page with checksum is quite impossible online.
If we commit online checksums before SLRU checksums, we will need very neat hacks if we decide to protect SLRU eventually.
What do you think about this problem?
One would be adjusted to work with the other, yes. It makes no sense to now allow online enabling once SLRU protection is in there, and it doesn't make sense for either of these patches to be blocking the other one for commit, though it would of course be best to get both included.
Makes no sense to *not* allow it, of course. Meaning yes, that should be handled.
We don' t need to convert from "page format with no support for checksums" (pre-11) to "page format with support for checksums" (11+) online.
We do need to convert from "page format with support for checksums but no checksums enabled" (11+) to "checksums enabled" online.
