Re: BUG #15074: psql client never returns when creating index (long running operation)

On Mon, Feb 19, 2018 at 08:26:48AM +0000, PG Bug reporting form wrote:
> When creating an index on a table containing approx. 100M records the psql
> client never returns when the index is eventually created on the server.
> This happens both in a psql client (9.6.6) on mac osx and using the libpq
> client via the ruby pg gem when using active records migrations.

Are you sure that the process got stuck? Perhaps it was spending a lot
of time processing and you did not wait for it to finish.

> When running the command directly op the postgres database server using the
> psql client it works as expected.
>
> The logs from the server:
> 2018-02-16 16:11:05 CET:82.161.205.254(59584):REDACTED(at)REDACTED_DB:[23141]:
> LOG: duration: 999618.165 ms
> 2018-02-16 16:11:05 CET:82.161.205.254(59584):REDACTED(at)REDACTED_DB:[23141]:
> LOG: could not receive data from client: Connection reset by peer
>
> The psql client just hangs, when trying to cancel the query client side
> (ctrl-c) the server logs says:
> 2018-02-16 16:13:53 CET:82.161.205.254(59961):[unknown](at)[unknown]:[25738]:
> LOG: PID 23141 in cancel request did not match any process

How is defined your schema? It could be possible that a
CHECK_FOR_INTERRUPTS() added in the code paths where the type of the
index you are creating is involved could help in making the system more
responsive to cancel requests.
--
Michael