On 2016-01-04 02:59, Mark Zealey wrote: > shutdown all unlogged tables will be truncated. Obviously with 9.5 we can now > alter tables to be logged/unlogged after insert but this will still write all > the inserts into the WAL. I haven't tried, but won't converting an unlogged table into a logged table write all the inserts at once instead of once per insert? Or are you wanting to do more bulk insert into that table later? > I can understand the requirement to truncate tables > with active IO at the point of unclean shutdown where you may get corrupted > data; but I'm interested to find out how easy it would be to not perform the > truncate for historical unlogged tables. Are you trying to avoid running a CHECKPOINT? Are you afraid the activity on the other tables will create too much I/O? > If the last data modification > statement was run more than eg 30 seconds or 1 minute before an unclean > shutdown (or the data was otherwise flushed to disk and there was no IO since > then) can we not assume that the data is not corrupted and hence not truncate > the unlogged tables? I have to admit that I have been surprised by this, it feels like unlogged tables are never written properly unless you do an explicit CHECKSUM. -- http://yves.zioup.com gpg: 4096R/32B0F416 -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
