Re: PATCH: logical_work_mem and logical streaming of large in-progress transactions
Amit Kapila <amit.kapila16@gmail.com>
Commits
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the thread's linked commits as JSON, with link sources.
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 Sun, Aug 30, 2020 at 2:43 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Sat, Aug 29, 2020 at 5:18 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
>
> > One more comment for which I haven't done anything yet.
> > +static void
> > +set_schema_sent_in_streamed_txn(RelationSyncEntry *entry, TransactionId xid)
> > +{
> > + MemoryContext oldctx;
> > +
> > + oldctx = MemoryContextSwitchTo(CacheMemoryContext);
> > +
> > + entry->streamed_txns = lappend_int(entry->streamed_txns, xid);
>
> > Is it a good idea to append xid with lappend_int? Won't we need
> > something equivalent for uint32? If so, I think we have a couple of
> > options (a) use lcons method and accordingly append the pointer to
> > xid, I think we need to allocate memory for xid if we want to use this
> > idea or (b) use an array instead. What do you think?
>
> BTW, OID is internally mapped to uint32, but using lappend_oid might
> not look good. So maybe we can provide an option for lappend_uint32?
> Using an array is also not a bad idea. Providing lappend_uint32
> option looks more appealing to me.
>
I thought about this again and I feel it might be okay to use it for
our case as after storing it in T_IntList, we primarily fetch it for
comparison with TrasnactionId (uint32), so this shouldn't create any
problem. I feel we can just discuss this in a separate thread and
check the opinion of others, what do you think?
Another comment:
+cleanup_rel_sync_cache(TransactionId xid, bool is_commit)
+{
+ HASH_SEQ_STATUS hash_seq;
+ RelationSyncEntry *entry;
+
+ Assert(RelationSyncCache != NULL);
+
+ hash_seq_init(&hash_seq, RelationSyncCache);
+ while ((entry = hash_seq_search(&hash_seq)) != NULL)
+ {
+ if (is_commit)
+ entry->schema_sent = true;
How is it correct to set 'entry->schema_sent' for all the entries in
RelationSyncCache? Consider a case where due to invalidation in an
unrelated transaction we have set the flag schema_sent for a
particular relation 'r1' as 'false' and that transaction is executed
before the current streamed transaction for which we are performing
commit and called this function. It will set the flag for unrelated
entry in this case 'r1' which doesn't seem correct to me. Or, if this
is correct, it would be a good idea to write some comments about it.
--
With Regards,
Amit Kapila.