> On 19/01/2023 01:23 CET Ian Lawrence Barwick <barwick@xxxxxxxxx> wrote: > > 2023年1月19日(木) 8:50 Erik Wienhold <ewie@xxxxxxxxx>: > > > > > On 19/01/2023 00:09 CET Hilbert, Karin <ioh1@xxxxxxx> wrote: > > > > > > I manage some PostgreSQL clusters on Linux. We have a Primary & two Standby > > > servers & for Production, there is also a DR server. We use repmgr for our HA > > > solution & the Standbys are cloned from the Primary using the repmgr standby > > > clone command. > > > > > > My manager asked for a report of all the user databases & their sizes for each > > > server in the cluster. I used the psql "\l+" command & then extracted the > > > database name & the size from the output. I expected the databases to be the > > > same size on the Standbys as on the Primary, but I found that some of the > > > databases were smaller on the Standby servers than on the Primary. > > > > > > For example, the output on the Primary for one of the user databases showed > > > as: 8997 kB, but on the Standbys, it was 8849 kB. > > > > The standbys could be missing some indexes because schema changes are not > > replicated and must be applied manually. > > This is incorrect; with streaming replication all changes applied on the primary > are applied on the standby. Thanks. I was thinking about logical replication. > (...) > > Could also be different page sizes. But that's a compilation option. What does > > SHOW block_size say on those systems? > > It is impossible to start a standby using binaries built with a > different block size to > the primary. Makes sense for streaming replication. -- Erik
