On Fri, 2022-05-13 at 13:31 +0100, Simon Riggs wrote: > The first was a discussion about a data structure needed by BDR about > 4 years ago. In the absence of a pluggable checkpoint, the solution > was forced to use a normal table, which wasn't very satisfactory.
I'm interested to hear more about this case. Are you developing it into a full table AM? In my experience with columnar, there's still a long tail of things I wish I had in the backend to better support complete table AMs. > The second was a more recent conversation with Mike Stonebraker, at > the end of 2021.. He was very keen to remove the buffer manager > entirely, which requires that we have a new smgr, which then needs > new > code to allow it to be written to disk at checkpoint time, which then > requires some kind of pluggable code at checkpoint time. (Mike was > also keen to remove WAL, but that's another story entirely!). I'm guessing that would be more of an experimental/ambitious project, and based on modified postgres anyway. > The last use case was unlogged indexes, which need to be read from > disk at startup or rebuilt after crash, which requires RmgrStartup to > work both with and without InRedo=true. That sounds like a core feature, in which case we can just refactor that for v16. It might be a nice cleanup for unlogged tables, too. I don't think your 002-v2 patch is particularly risky, but any reluctance at all probably pushes it to v16 given that it's so late in the cycle. Regards, Jeff Davis