Re: Problem Observed in behavior of Create Index Concurrently and Hot Update

BTW, I was thinking that the DROP INDEX CONCURRENTLY logic needed to be:

1. Unset indisvalid, commit, wait out all reading transactions.

2. Unset indisready, commit, wait out all writing transactions.

3. Unset indislive, commit (with parent table relcache flush),
wait out all reading-or-writing transactions.

4. Drop the index.

However, I wonder whether we couldn't combine steps 2 and 3, ie once
there are no readers of the index go directly to the "dead" state.
I don't see a need for a period where the index isn't being inserted
into but is still used for HOT-safety decisions.
        regards, tom lane