5 ms·

Please go on.

• throwaway894345 5y ago
  > PostgreSQL uses the term cluster to refer to a “cluster” of databases, as opposed to the usual notion of a group of servers or VMs working in a co-ordinated fashion. https://www.opsdash.com/blog/postgresql-cluster.html https://www.opsdash.com/blog/postgresql-cluster.html Note that the "databases" above are logical databases, not database hosts.
  • pcthrowaway 5y ago
    So according to this usage, one database instance with a few databases would be a cluster?
    • throwaway894345 5y ago
      I'm not an expert, but as far as I can tell, even a single database instance with a single database (or maybe no databases at all?) could constitute a "cluster".
  • snthpy 5y ago
    Thank you for this. I didn't realise this and for the past few years have been thinking that I seem to be the only one that runs only a single database host as everyone else seems to have "clusters". I never realised this just means multiple databases.
• pdpi 5y ago
  A Postgres cluster is, roughly speaking, a server instance. That is, if you run two copies of postgres on the same box (One on the default 5432 port, another on, say, 6543) and have each of those copies manage its own independent config, data, etc, then those instances are what Postgres calls a cluster.
• munk-a 5y ago
  Clustering is, besides all the other definitions you're seeing here, a table property. A clustered table is a table that has, on disk, been aligned with a certain index[1] - each table can only be clustered to a single index and it essentially means that row retrieval for that specific index is much more efficient, it basically gets you one covering index for free. 1. https://www.postgresql.org/docs/current/sql-cluster.html https://www.postgresql.org/docs/current/sql-cluster.html