On Mon, Jul 11, 2016 at 11:01 PM, Binand Sethumadhavan <binand@gmail.com> wrote:
We have a postgresql 9.2 instance pair (master+slave) supporting our online application. We have a postgresql 9.5 instance which contains a dump of the above database.
The primary purpose of the dump database is to facilitate analysis. It is updated from the slave by way of a perl script and psql. Master has archival policies etc. in place but dump contains complete historic data.
My problem is that when the dump job runs, queries pause or when heavy analysis queries run, dump process pauses. This creates significant problems. One particular use-case has a production application picking analyzed data from the dump database and running a campaign based on that.
It is basically a hack to implement data warehouse, ETL, datamarts, analysis & reporting and campaign management via a set of perl/shell/sql scripts. It used to work fine, but now with analysis workloads increasing it is creating problems.
I'd like to know where to go next; because at the moment I'm out of ideas. I do not have the budget for a paid solution.
Basically, I'm looking for suggestions on architecture and implementation of such a system. If there are any web references please mention them too.
We use a tool that I've been working on called mimeo to do logical (per-table) replication to move data to a data warehouse system like you have. Mimeo has several replication methods available, the most commonly used being trigger based replication (DML replay). Some other replication methods that can be more efficient are available as well, but only work in specific situations.
There's another extension in the works called pglogical, which uses the newer logical WAL streaming method available in 9.4. It's much more efficient, but not quite as flexible and also requires all systems involved be on the same version.
