Failing to allocate a memory segment of only 1MB seems suspicious. What are your hardware specs? You might want to look at your memory & parallel query settings in postgresql.conf--perhaps some of those are set too high relative to your server's memory. I wouldn't really expect queries to be slow on 99GB, by the way. That is not a large database. Partitioning is reasonable if you want to prune old data periodically, as then you can just drop old partitions. But unless your queries are regularly have to perform table scans, I wouldn't expect them to be slow. And if they are performing table scans, you'd need to investigate how to fix that--what indexes to add. Partitioning will get you incremental performance gains in such a case, while the right index will get you exponential gains.
