Horton

Re: Minimal logical decoding on standbys

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

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From: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>, Jeff Davis <pgsql@j-davis.com>, Thomas Munro <thomas.munro@gmail.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Ibrar Ahmed <ibrar.ahmad@gmail.com>, Amit Khandekar <amitdkhan.pg@gmail.com>, fabriziomello@gmail.com, tushar <tushar.ahuja@enterprisedb.com>, Rahila Syed <rahila.syed@2ndquadrant.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Melanie Plageman <melanieplageman@gmail.com>
Date: 2023-04-04T12:34:19Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Reduce the log level in 035_standby_logical_decoding.pl.

  2. 035_standby_logical_decoding: Add missing waits for replication

  3. For cascading replication, wake physical and logical walsenders separately

  4. Handle logical slot conflicts on standby

  5. Support invalidating replication slots due to horizon and wal_level

  6. Prevent use of invalidated logical slot in CreateDecodingContext()

  7. Replace replication slot's invalidated_at LSN with an enum

  8. Pass down table relation into more index relation functions

  9. Assert only valid flag bits are passed to visibilitymap_set()

  10. Remove unused _bt_delitems_delete() argument.

  11. Add xl_btree_delete optimization.

Hi,

On 4/4/23 1:43 PM, Amit Kapila wrote:
> On Tue, Apr 4, 2023 at 3:14 PM Drouvot, Bertrand
> <bertranddrouvot.pg@gmail.com> wrote:
>>
> 
> 
> +static inline bool
> +LogicalReplicationSlotXidsConflict(ReplicationSlot *s, TransactionId xid)
> +{
> + TransactionId slot_xmin;
> + TransactionId slot_catalog_xmin;
> +
> + slot_xmin = s->data.xmin;
> + slot_catalog_xmin = s->data.catalog_xmin;
> +
> + return (((TransactionIdIsValid(slot_xmin) &&
> TransactionIdPrecedesOrEquals(slot_xmin, xid)) ||
> 
> For logical slots, slot->data.xmin will always be an
> InvalidTransactionId. It will only be set/updated for physical slots.
> So, it is not clear to me why in this and other related functions, you
> are referring to and or invalidating it.
> 

I think you're right that invalidating/checking only on the catalog xmin is
enough for logical slot (I'm not sure how I ended up taking the xmin into account but
that seems useless indeed).

I'll submit a new version to deal with the catalog xmin only, thanks!

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com