Re: A few questions to real pgsql gurus
От | Shridhar Daithankar |
---|---|
Тема | Re: A few questions to real pgsql gurus |
Дата | |
Msg-id | 3E5A2623.21332.37F7E1@localhost обсуждение исходный текст |
Ответ на | A few questions to real pgsql gurus ("mike McGire" <mmcgire@hotmail.com>) |
Список | pgsql-general |
On 24 Feb 2003 at 5:53, mike McGire wrote: > Hi > > We are working on a project and our client wants to use PostgreSQL as the > backend, since it will be a very mission critical 24x7 live environment, I > have to know a few things about postgresql before we can consider it. > > 1) Backups : Going through the documents I can see that there are no > incremental backups available in postgres yet, I may have overlooked it, > therefore, I would like to know: > > a) Am I right on the incremental backup ? Not exactly. There are replication solutions which would sync a WAL file between two hosts. That is good enough incremental backup in 16MB chunks. However it is all or none solution. You can not backup a single database this way. Your entire installation will be backed up. Google/list archives for links. > b) what would be the performance impact of taking frequent backups > ( Lets say every 2-3 hours ). Depends upon data size if you are going to use pg_dump. most important aspect I can see is backup process chewing disk bandwidth which can be a eral choker if you are working on data parallely and your database is quite large. > c) Is it possible to restore tables selectively from a backup. If you dump them selectively, yes. Afterall it is just ascii dump of insert statements. > d) Can we do a point in time restore from the backups. Depends. If you have WAL files safe and postgresql data is safe, yes. But that is not true PITR for many guys. > > 2) Failover : > > a) is it possible to create a cluster of 2 (primary & secondary) > databases. I believe so. But no links handy. > b) is it possible to configure an auto-failover to the secondary > database in case primary dies. If you have heartbeat service installed and using async replication, like I mentioned above, you should have a database which is current till latest WAL segment. Otherwise you have to user a sync. replication which is costly in performance I believe... > c) how reliable the replication is in postgresql, can a) & b) be > implemented using replication. It works for many guys. A beta/pilot at your own site is recommended. > 3) Functions & triggers : Our project would be heavily dependent on > functions and triggers : > > a) I see postgresql supports many procedural languages, so what > should be the preferred language to be used for functions/ > procedures ( i.e. is PL/PGSQL as fast as C is etc ). Writng triggers in C would be fast for performance but may not be as fast for development. Rule of thumb is PL/PgSQL is usually good enough.. HTH Bye Shridhar -- design, v.: What you regret not doing later on.
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