Re: PATCH: logical_work_mem and logical streaming of large in-progress transactions
Amit Kapila <amit.kapila16@gmail.com>
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API reference →
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Tighten the concurrent abort check during decoding.
- 2ce353fc1902 14.0 landed
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Improve hash_create()'s API for some added robustness.
- b3817f5f7746 14.0 landed
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Use HASH_BLOBS for xidhash.
- a1b8aa1e4eec 14.0 landed
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Fix initialization of RelationSyncEntry for streaming transactions.
- 69bd60672af6 14.0 landed
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Remove unused function declaration in logicalproto.h.
- ddd5f6d2609b 14.0 landed
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Add additional tests to test streaming of in-progress transactions.
- 58b5ae9d62bd 14.0 landed
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Fix inline marking introduced in commit 464824323e.
- ac15b499f7f9 14.0 landed
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Add support for streaming to built-in logical replication.
- 464824323e57 14.0 landed
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Fix the SharedFileSetUnregister API.
- 4ab77697f67a 14.0 landed
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Fix comment in procarray.c
- 77c7267c37f7 14.0 cited
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Suppress compiler warning in non-cassert builds.
- e942af7b8261 14.0 cited
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Extend the BufFile interface.
- 808e13b282ef 14.0 landed
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Mark a few logical decoding related variables with PGDLLIMPORT.
- b48cac3b10a0 14.0 landed
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Implement streaming mode in ReorderBuffer.
- 7259736a6e5b 14.0 landed
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Extend the logical decoding output plugin API with stream methods.
- 45fdc9738b36 14.0 landed
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WAL Log invalidations at command end with wal_level=logical.
- c55040ccd017 14.0 landed
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Immediately WAL-log subtransaction and top-level XID association.
- 0bead9af484c 14.0 landed
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Allow logical replication to transfer data in binary format.
- 9de77b545313 14.0 cited
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Only superuser can set sslcert/sslkey in postgres_fdw user mappings
- cebf9d6e6ee1 13.0 cited
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Track statistics for spilling of changes from ReorderBuffer.
- 9290ad198b15 13.0 landed
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Add logical_decoding_work_mem to limit ReorderBuffer memory usage.
- cec2edfa7859 13.0 landed
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logical decoding: process ASSIGNMENT during snapshot build
- bac2fae05c77 13.0 cited
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Emit invalidations to standby for transactions without xid.
- c6ff84b06a68 9.6.0 cited
On Wed, May 27, 2020 at 8:22 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Tue, May 26, 2020 at 7:45 AM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> >
> >
> > Okay, sending again.
>
> While reviewing/testing I have found a couple of problems in 0005 and
> 0006 which I have fixed in the attached version.
>
I haven't reviewed the new fixes yet but I have some comments on
0008-Add-support-for-streaming-to-built-in-replicatio.patch.
1.
I think the temporary files (and or handles) used for storing the
information of changes and subxacts are getting leaked in the patch.
At some places, it is taken care to close the file but cases like
apply_handle_stream_commit where if any error occurred in
apply_dispatch(), the file might not get closed. The other place is
in apply_handle_stream_abort() where if there is an error in ftruncate
the file won't be closed. Now, the bigger problem is with changes
related file which is opened in apply_handle_stream_start and closed
in apply_handle_stream_stop and if there is any error in-between, we
won't close it.
OTOH, I think the worker will exit on an error so it might not matter
but then why we are at few other places we are closing it before the
error? I think on error these temporary files should be removed
instead of relying on them to get removed next time when we receive
changes for the same transaction which I feel is what we do in other
cases where we use temporary files like for sorts or hashjoins.
Also, what if the changes file size overflows "OS file size limit"?
If we agree that the above are problems then do you think we should
explore using BufFile interface (see storage/file/buffile.c) to avoid
all such problems?
2.
apply_handle_stream_abort()
{
..
+ /* discard the subxacts added later */
+ nsubxacts = subidx;
+
+ /* write the updated subxact list */
+ subxact_info_write(MyLogicalRepWorker->subid, xid);
..
}
Here, if subxacts becomes zero, then also subxact_info_write will
create a new file and write checksum. I think subxact_info_write
should have a check for nsubxacts > 0 before writing to the file.
3.
apply_handle_stream_commit(StringInfo s)
{
..
+ /*
+ * send feedback to upstream
+ *
+ * XXX Probably should send a valid LSN. But which one?
+ */
+ send_feedback(InvalidXLogRecPtr, false, false);
..
}
Why do we need to send the feedback at this stage after applying each
message? If we see a non-streamed case, we never send_feedback after
each message. So, following that, I don't see the need to send it here
but if you see any specific reason then do let me know? And if we
have to send feedback, then we need to decide the appropriate values
as well.
--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com