Re: Newly created replication slot may be invalidated by checkpoint
Alexander Korotkov <aekorotkov@gmail.com>
From: Alexander Korotkov <aekorotkov@gmail.com>
To: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>,
Vitaly Davydov <v.davydov@postgrespro.ru>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>, "suyu.cmj" <mengjuan.cmj@alibaba-inc.com>, tomas <tomas@vondra.me>, michael <michael@paquier.xyz>, "bharath.rupireddyforpostgres" <bharath.rupireddyforpostgres@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>
Date: 2025-12-18T12:11:24Z
Lists: pgsql-hackers
On Thu, Dec 11, 2025 at 9:29 AM Zhijie Hou (Fujitsu) <houzj.fnst@fujitsu.com> wrote: > On Thursday, December 11, 2025 3:09 PM Zhijie Hou (Fujitsu) <houzj.fnst@fujitsu.com> wrote: > > I reviewed that approach, and I think the main distinction lies in whether to > > use a new LWLock to serialize the process or rely on an existing lock. > > Introducing a new LWLock in back branches would alter the size of > > MainLWLockArray and affect > > NUM_INDIVIDUAL_LWLOCKS/LWTRANCHE_FIRST_USER_DEFINED. > > Although this may not directly impact user applications since users typically > > use standard APIs like RequestNamedLWLockTranche and > > LWLockNewTrancheId to add private LWLocks, it still has a slight risk. > > Additionally, using an existing lock could keep code similarity with the HEAD, > > which can be helpful for future bug fixes and analysis. > > BTW, I searched the git history and can only find 2 old commits that adds lwlock > On stable branches, but both of are fixing serious problems such as > data corruption / loss issues. I understand that that was done due to more serious reasons than ours. As I get, it run smoothly. At least, I can't remember we have been reported with any issues regarding to this change. Can we assume this is kind of "tested" and add new LWLock to both master and back branches? I think this would be good in terms of clarity and minimal possible divergence of back branches. ------ Regards, Alexander Korotkov Supabase