Re: CREATE INDEX and HOT - revised design

As stated in later email, I think we should focus on the xid idea
because it is more flexible.

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Gregory Stark wrote:
> 
> "Bruce Momjian" <bruce@momjian.us> writes:
> 
> > We also add a boolean to pg_class to indicate no new HOT chains should be
> > created and set that to false once the new index is created.
> 
> Since we have all the index info in the relcache we could just skim through
> all the indexes when we build the relcache and decide then whether we're
> allowed to do HOT updates. That avoids problems if we crash while HOT updates
> are disabled.
> 
> I think we need to think harder about exactly what test we would perform
> against this xid to determine the two relevant tests, 
> 
> a) whether to prohibit HOT updates (because the index is "too new")
> 
> b) whether to ignore HOT update chains when we use the index (because it's
>    "too new" and any HOT update chains predate it).
> 
> I fear it may imply that we have to keep performing cold updates until the
> first vacuum after the xid expires.
> 
> -- 
>   Gregory Stark
>   EnterpriseDB          http://www.enterprisedb.com
> 
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--  Bruce Momjian  <bruce@momjian.us>          http://momjian.us EnterpriseDB
http://www.enterprisedb.com
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