Historically, the checkpointer process use palloc() into AbsorbSyncRequests() function. Therefore, the checkpointer does not expect to receive a request larger than 1 GB.
Yeah. And the most unpleasant thing is it won't simply fail with an error or helpful message suggesting a workaround (reduce the amount of shared memory). Checkpointer will just "stuck".
AFAICS, we have a few options:
1. Leave it as it is, but fatal on allocation of the chunk more than 1G.
2. Use palloc_extended with MCXT_ALLOC_HUGEflag.
3. Do not use any allocation and use CheckpointerShmem->requestsdirectly in case of > 1G size of the required allocation.
Case (3) is not an option, in my opinion. So, we following (1) or (2). Personally, I'm for (2), PFA v0 patch.
