pgsql: Introduce transaction_timeout

Introduce transaction_timeout

This commit adds timeout that is expected to be used as a prevention
of long-running queries. Any session within the transaction will be
terminated after spanning longer than this timeout.

However, this timeout is not applied to prepared transactions.
Only transactions with user connections are affected.

Discussion: https://postgr.es/m/CAAhFRxiQsRs2Eq5kCo9nXE3HTugsAAJdSQSmxncivebAxdmBjQ%40mail.gmail.com
Author: Andrey Borodin <amborodin(at)acm(dot)org>
Author: Japin Li <japinli(at)hotmail(dot)com>
Author: Junwang Zhao <zhjwpku(at)gmail(dot)com>
Reviewed-by: Nikolay Samokhvalov <samokhvalov(at)gmail(dot)com>
Reviewed-by: Andres Freund <andres(at)anarazel(dot)de>
Reviewed-by: Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com>
Reviewed-by: bt23nguyent <bt23nguyent(at)oss(dot)nttdata(dot)com>
Reviewed-by: Yuhang Qiu <iamqyh(at)gmail(dot)com>

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/51efe38cb92f4b15b68811bcce9ab878fbc71ea5

Modified Files
--------------
doc/src/sgml/config.sgml | 36 ++++++++++++
src/backend/access/transam/xact.c | 4 ++
src/backend/postmaster/autovacuum.c | 2 +
src/backend/storage/lmgr/proc.c | 1 +
src/backend/tcop/postgres.c | 46 +++++++++++++++-
src/backend/utils/errcodes.txt | 1 +
src/backend/utils/init/globals.c | 1 +
src/backend/utils/init/postinit.c | 10 ++++
src/backend/utils/misc/guc_tables.c | 11 ++++
src/backend/utils/misc/postgresql.conf.sample | 1 +
src/bin/pg_dump/pg_backup_archiver.c | 1 +
src/bin/pg_dump/pg_dump.c | 2 +
src/bin/pg_rewind/libpq_source.c | 1 +
src/include/miscadmin.h | 1 +
src/include/storage/proc.h | 1 +
src/include/utils/guc_hooks.h | 1 +
src/include/utils/timeout.h | 1 +
src/test/isolation/Makefile | 3 +
src/test/isolation/expected/timeouts-long.out | 69 +++++++++++++++++++++++
src/test/isolation/expected/timeouts.out | 79 ++++++++++++++++++++++++++-
src/test/isolation/isolation_schedule | 1 +
src/test/isolation/specs/timeouts-long.spec | 35 ++++++++++++
src/test/isolation/specs/timeouts.spec | 40 +++++++++++++-
23 files changed, 343 insertions(+), 5 deletions(-)