Re: Truncation of UNLOGGED tables upon restart.

From: Ravi Krishna <srkrishna1(at)aol(dot)com>
To: david(dot)g(dot)johnston(at)gmail(dot)com, pgsql-general(at)lists(dot)postgresql(dot)org
Subject: Re: Truncation of UNLOGGED tables upon restart.
Date: 2018-11-01 21:20:19
Message-ID: 1177060548.6477958.1541107219801@mail.yahoo.com
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> There is no such thing as a "read only" table in PostgreSQL.  All tables are read/write no matter that frequency of either event.  There is nothing > inherently special about "no writes for 4 days" and "no writes for 10 seconds" that would allow for a distinction to be made.  There could be write > in progress on the table just as it crashes Friday.

I am aware that unlogged tables have no entries in WAL, but I assumed (incorrectly) that PG will at least keep track whether any writes was done on a table since last checkpoint, and if none, it will find no reason to truncate it.

The use case I was thinking about is that if we have to load a large set of data every weekend and use it for reporting until next weekend, why not create those tables as unlogged.

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