Thanks for your reply. These patches look good to me!
> The only readily-reachable error case in BeginInternalSubTransaction
> is this specific one about IsInParallelMode, which was added later
> than the original design and evidently with not a lot of thought or
> testing. The comment for it speculates about whether we could get
> rid of it, so I wonder if our thoughts about this ought to go in that
> direction.
IMHO, there are other error reports in the function BeginInternalSubTransaction(), like
```
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory"),
errdetail("Failed on request of size %zu in memory context \"%s\".",
size, context->name)));
```
we cannot avoid this crash by just getting rid of IsInParallelMode().
And in my test, the server won't crash in the plperl test.
With regards,
Hao Zhang
I wrote:
> The only readily-reachable error case in BeginInternalSubTransaction
> is this specific one about IsInParallelMode, which was added later
> than the original design and evidently with not a lot of thought or
> testing. The comment for it speculates about whether we could get
> rid of it, so I wonder if our thoughts about this ought to go in that
> direction.
After thinking a bit more I wonder why we need that error check at all.
Why isn't it sufficient to rely on GetNewTransactionId()'s check that
throws an error if a parallelized subtransaction tries to obtain an XID?
I don't see why we'd need to "synchronize transaction state" about
anything that never acquires an XID.
regards, tom lane