Re: Hot standby, slot ids and stuff - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: Hot standby, slot ids and stuff
Date
Msg-id 496662B0.5020208@enterprisedb.com
Whole thread Raw
In response to Re: Hot standby, slot ids and stuff  (Simon Riggs <simon@2ndQuadrant.com>)
Responses Re: Hot standby, slot ids and stuff  (Simon Riggs <simon@2ndQuadrant.com>)
List pgsql-hackers
Simon Riggs wrote:
> If you want to do things a different way you need to say what you want
> to do and what effects those changes will have. 

I want to reduce the coupling between the primary and the master. The 
less they need to communicate, the better. I want to get rid of slotid, 
and as many of the other extra information carried in WAL records that I 
can. I believe that will make the patch both simpler and more robust.

> Are there tradeoffs? If so what are they?

I don't think there's any big difference in user-visible behavior. 
RecordKnownAssignedTransactionId now needs to be called for every xlog 
record as opposed to just the first record where an xid appears, because 
I eliminated the hint flag in WAL to mark those records. And it needs to 
look up the recover proc by xid, instead of using the slot id. But I 
don't think that will have a significant impact on performance.

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com


pgsql-hackers by date:

Previous
From: Heikki Linnakangas
Date:
Subject: Re: Hot standby, slot ids and stuff
Next
From: Martijn van Oosterhout
Date:
Subject: Re: Significant oversight in that #include-removal script