Horton

Re: logical replication worker accesses catalogs in error context callback

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Cc: Zhihong Yu <zyu@yugabyte.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Andres Freund <andres@anarazel.de>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Peter Eisentraut <peter_e@gmx.net>, Petr Jelinek <petr@2ndquadrant.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: 2021-02-04T12:12:47Z
Lists: pgsql-hackers 
On Thu, Feb 4, 2021 at 5:38 PM Bharath Rupireddy
<bharath.rupireddyforpostgres@gmail.com> wrote:
>
> On Thu, Feb 4, 2021 at 4:00 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > > > About 0001, have we tried to reproduce the actual bug here which means
> > > > when the error_callback is called we should face some problem? I feel
> > > > with the correct testcase we should hit the Assert
> > > > (Assert(IsTransactionState());) in SearchCatCacheInternal because
> > > > there we expect the transaction to be in a valid state. I understand
> > > > that the transaction is in a broken state at that time but having a
> > > > testcase to hit the actual bug makes it easy to test the fix.
> > >
> > > I have not tried hitting the Assert(IsTransactionState() in
> > > SearchCatCacheInternal. To do that, I need to figure out hitting
> > > "incorrect binary data format in logical replication column" error in
> > > either slot_modify_data or slot_store_data so that we will enter the
> > > error callback slot_store_error_callback and then IsTransactionState()
> > > should return false i.e. txn shouldn't be in TRANS_INPROGRESS.
> > >
> >
> > Even, if you hit that via debugger it will be sufficient or you can
> > write another elog/ereport there to achieve the same. The exact test
> > case to hit that error is not mandatory.
>
> Thanks Amit. I verified it with gdb. I attached gdb to the logical
> replication worker. In slot_store_data's for loop, I intentionally set
> CurrentTransactionState->state = TRANS_DEFAULT,
>

What happens if you don't change CurrentTransactionState->state?

-- 
With Regards,
Amit Kapila.

Commits

  1. Avoid doing catalog lookups in postgres_fdw's conversion_error_callback.

  2. Don't try to print data type names in slot_store_error_callback().

  3. logical replication: fix OID type mapping mechanism

  4. Improve sys/catcache performance.

  5. Logical replication