Re: Deprecating Hash Indexes

On Monday, October 15, 2012 07:03:35 PM Simon Riggs wrote:
> On 15 October 2012 15:19, Andres Freund said...
> 
> > I vote for at least logging a wal record when a hash index is modified
> > which uses incomplete actions to set 'indisready = false' in case its
> > replayed. That should only use a rather minor amount of code and should
> > help users to find problems faster.
> 
> Good idea, though might be harder than it first appears.

> How do we issue just one of those per checkpoint, to minimise WAL?

I was thinking per checkpoint, per backend in order to not add any new locks.

> How do we make that change with a physical update WAL? Non-transactional
> update? During recovery?

Thats why I suggested using the incomplete actions/cleanup stuff, so we can do 
the change when replay finished. Thats not enough for HS though... Can we get 
away with putting a if (RecoveryInProgress()) ereport(...) in there?

Greetings,

Andres
-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
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