Re: BUG #14279: Logical decoding misses a transaction completely

>>>>> "marko" == marko <marko(at)joh(dot)to> writes:

marko> The problem seems to be that ReorderBufferCommitChild()
marko> overwrites the main transaction's base_snapshot with a NULL
marko> because it thinks the subtransaction's base_snapshot_lsn=0 is
marko> older than the main transaction's actual snapshot

i.e. here in ReorderBufferCommitChild:

/*
* Pass the our base snapshot to the parent transaction if it doesn't have
* one, or ours is older. That can happen if there are no changes in the
* toplevel transaction but in one of the child transactions. This allows
* the parent to simply use it's base snapshot initially.
*/
if (txn->base_snapshot == NULL ||
txn->base_snapshot_lsn > subtxn->base_snapshot_lsn)
{

it's possible for subtxn to exist, but for subtxn->base_snapshot to be
NULL and base_snapshot_lsn to be 0, and obviously propagating this to
txn is wrong.

--
Andrew (irc:RhodiumToad)