Re: vacuum confusion

I've just noticed that the v8 docs are MUCH better in explaining this 
than the 7.4.6 docs that I'm using (since I'm using 7.4.6 in production).

Perhaps if the same texts


play=# VACUUM;
WARNING:  some databases have not been vacuumed in 1613770184 transactions
HINT:  Better vacuum them within 533713463 transactions, or you may have 
a wraparound failure.
VACUUM


and warning


To be sure of safety against transaction wraparound, it is necessary to 
vacuum every table, including system catalogs, in every database at 
least once every billion transactions. We have seen data loss situations 
caused by people deciding that they only needed to vacuum their active 
user tables, rather than issuing database-wide vacuum commands. That 
will appear to work fine ... for a while.


were added to the 7.4.x docs that would help others too.

Thanks

John Sidney-Woollett

Richard Huxton wrote:

> John Sidney-Woollett wrote:
> 
>> Ah.., no we're not vacuuming template0 or 1.
>>
>> I didn't realise that the transaction ID would be stored here - I 
>> assumed that they'd be in our database.
>>
>> Do I need to need to (plain) vacuum, or vacuum full these template0 
>> and template1? And is this something that can be done once a week 
>> rather than every night (like our main database)?
> 
> 
> Ah! Found the section of the manuals - see "Routine Database Maintenance 
> Tasks" for details.
> 
> AFAIK it's a simple vacuum and once a week is more than enough. The 
> manual recommends once every 500million transactions, though you can 
> leave it longer.
> 
> -- 
>   Richard Huxton
>   Archonet Ltd
> 
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