(An intermittent series on PostgreSQL parameters whose default settings you should change.)

Here’s my preferred logging configuration:

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log_destination = 'csvlog'
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logging_collector = on
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log_directory = '/var/log/postgresql'
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log_filename = 'postgresql-%Y%m%d-%H%M%S.log'
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log_rotation_size = 1GB
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log_rotation_age = 1d
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log_min_duration_statement = 250ms
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log_checkpoints = on
 

(An intermittent series on PostgreSQL parameters whose default settings you should change.)

By default archive_mode is set to off, and thus archive_command is ignored. Even if you are not going to be using WAL archiving, you should change these. You can use settings such as:

archive_mode = on
archive_command = '/bin/true'

It requires

(An intermittent series on PostgreSQL parameters whose default settings you should change.)

Introduced in PostgreSQL 9.5, wal_compression is off by default, but you should probably turn it on.

First, what does it do? The documentation helpfully explains:

When this parameter is on, the PostgreSQL server compresses a full page image written to WAL when full_page_writes is

Ultimately, a PostgreSQL database is just files, and those files have to be stored somewhere. Absent tablespaces, they are all stored in a single directory structure, traditionally called PGDATA. While smaller instllations can just use the defaults associated with the packaging, larger databases are often installed on their own volume with its own mountpoint.

Two rules to keep in

The slides from my talk at Nordic PGDay, Why PostgreSQL is Terrible, are now available.

So many types of replication, so little time! What kind of PostgreSQL replication should you use?

I want a standby server to take over if the primary fails.

Use streaming replication.

I want to do read-only queries for load balancing.

Use streaming replication, but be aware that the replica receiving the queries may fall

One of the essentials of any database system is that a transaction is either in progress, committed, or rolled back. But consider what happens if…

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BEGIN;
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UPDATE table SET money=money+100000;
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COMMIT;
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-- And you get an error that the server has disconnected

Did that transaction commit, or didn’t it? You

We recently were asked by a client to look at a strange replication situation. Replication had simply stopped from a primary to a streaming replication secondary. Everything looked fine:

• The secondary was connected to the primary, as we could see in pg_stat_replication.
• The secondary was not receiving any queries, so delays in applying incoming page changes

The slides for “Humans do not have a primary key” as presented at PGConf EU are available here. Three links from the presentation are:

• Personal names around the world
• Kudzu and the California Marriage Amendment
• General Data Protection Regulations in the EU

I’ll be presenting “Humans do not have a primary key” at PGOpen SV today. Two links from the presentation are:

• Personal names around the world
• Kudzu and the California Marriage Amendment