Re: Introduce XID age and inactive timeout based replication slot invalidation

shveta malik <shveta.malik@gmail.com>

From: shveta malik <shveta.malik@gmail.com>
To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Nathan Bossart <nathandbossart@gmail.com>, Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, shveta malik <shveta.malik@gmail.com>
Date: 2024-03-15T07:19:07Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →
  1. Add a test for commit ac0e33136a using the injection point.

  2. Invalidate inactive replication slots.

  3. Fix incorrect slot type in BuildTupleHashTableExt

  4. Allow synced slots to have their inactive_since.

  5. Change last_inactive_time to inactive_since in pg_replication_slots.

  6. Track last_inactive_time in pg_replication_slots.

  7. Track invalidation_reason in pg_replication_slots.

  8. Add option force_initdb to PostgreSQL::Test::Cluster:init()

  9. Add a failover option to subscriptions.

  10. Allow setting failover property in the replication command.

  11. Allow to enable failover property for replication slots via SQL API.

  12. Track conflict_reason in pg_replication_slots.

  13. Log messages for replication slot acquisition and release.

  14. Remove vacuum_defer_cleanup_age

  15. Fix corruption due to vacuum_defer_cleanup_age underflowing 64bit xids

  16. meson: Add initial version of meson based build system

On Thu, Mar 14, 2024 at 7:58 PM Bharath Rupireddy
<bharath.rupireddyforpostgres@gmail.com> wrote:
>
> While we wait to hear from others on this, I'm attaching the v9 patch
> set implementing the above idea (check 0001 patch). Please have a
> look. I'll come back to the other review comments soon.
>

patch002:

1)
I would like to understand the purpose of 'inactive_count'? Is it only
for users for monitoring purposes? We are not using it anywhere
internally.

I shutdown the instance 5 times and found that 'inactive_count' became
5 for all the slots created on that instance. Is this intentional? I
mean we can not really use them if the instance is down.  I felt it
should increment the inactive_count only if during the span of
instance, they were actually inactive i.e. no streaming or replication
happening through them.


2)
slot.c:
+ case RS_INVAL_XID_AGE:
+ {
+ if (TransactionIdIsNormal(s->data.xmin))
+ {
+                          ..........
+ }
+ if (TransactionIdIsNormal(s->data.catalog_xmin))
+ {
+                          ..........
+ }
+ }

Can we optimize this code? It has duplicate code for processing
s->data.catalog_xmin and s->data.xmin. Can we create a sub-function
for this purpose and call it twice here?

thanks
Shveta