ITAGAKI Takahiro <itagaki.takahiro@oss.ntt.co.jp> writes:
> Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> Can we do REINDEX
>>> holding only shared lock on the index?
>>
>> No. When you commit the reindex, the old copy of the index will
>> instantaneously disappear; it will not do for someone to be actively
>> scanning that copy.
> Hmm... Is it ok if the index will *not* instantaneously disappear?
It's not impossible but I really question whether it'd be worth the
complexity. There was something very closely related just yesterday
about whether DROP INDEX has to take exclusive lock ...
regards, tom lane