Re: Improve warnings around CREATE INDEX CONCURRENTLY

Excerpts from Greg Smith's message of mié may 25 17:04:03 -0400 2011:

> Sure. Simon's command string idea might work better, and doing some
> extra lock decoration as you suggested in the above thread would be
> another level of improvement. We should pick up redesign later on the
> main list. You can at least count me in as someone who wants to see
> this improved now.

Great

> Back to the doc patch I submitted...is that a useful step toward making
> this issue visible enough to users for now to help?

Sure, why not? I thought I could choose my bikeshed color while I was
here, how about

+ second and third transaction. All active transactions at the time the
+ second table scan starts, not just ones that already involve the table,
+ have the potential to block the concurrent index creation until they
+ finish. When checking for transactions that
+ could still use the original index, concurrent index creation advances
+ through potentially interfering older transactions one at a time,
+ obtaining shared locks on their virtual transaction identifiers to wait for
+ them to complete.

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