By Franck Pachot . In a recent tweet I wanted to highlight the importance of knowing what you measure with pgbench, because looking at “Transactions per second” without knowing if you are in shared buffer cache hits, or filesystem cache hit, or storage cache hit, or physical read… is just meaningless: When you run the #postgres builtin pgbench, you should…
PostgreSQL, like all other database engines, modifies the table and index blocks in shared buffers. People think that the main goal of buffered reads is to act as a cache to avoid reading from disk. But that’s not the main reason as this is not mandatory. For example PostgreSQL expects that the filesystem cache is used. The primary goal of…
By Franck Pachot . Having a database in the cloud is very nice. You add storage with a few clicks. You don’t have to think about the storage type (DAS, SAN, NAS), size of disks, stripe size, SSD, etc. But do you have the performance you expect? I’ve tested I/O in the Cloud that just opened for Europe, so that…
