Re: POC: make mxidoff 64 bits

The biggest problem with compression, in my opinion, is that losing
even one byte causes the loss of the entire compressed block in the
worst case scenario. After all, we still don't have checksums for the
SLRU's, which is a shame by itself.

Again, I'm not against the idea of compression, but the risks need to
be considered.

As a software developer, I definitely want to implement compression and
save a few gigabytes. However, given my previous experience using
Postgres in real-world applications, reliability at the cost of several
gigabytes would not have caused me any trouble. Just saying.--