621 - WARNING - persist_presence_changes-99641 - [TXN OPERROR] {update_presence-34728b} could not serialize access due to concurrent update

[matrixbot]

This issue has been migrated from #16734.

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Description

The are some Warnings on Synapse 1.89

Steps to reproduce

I have this error on the log.

Homeserver

auto-host

Synapse Version

1.89

Installation Method

pip (from PyPI)

Database

PosgreeSQL 11

Workers

Single process

Platform

CentOS7 VM Python installation

Configuration

No response

Relevant log output

2023-11-23 11:42:50.459	cd11-comm.on-gofast.com
2023-11-23 12:42:40,592 - synapse.storage.txn - 621 - WARNING - persist_presence_changes-99641 - [TXN OPERROR] {update_presence-34728b} could not serialize access due to concurrent update

Anything else that would be useful to know?

No response

[pgiblock]

I am receiving similar warnings:

2024-02-23 22:10:19,620 - synapse.storage.txn - 737 - WARNING - GET-33579- [TXN OPERROR] {update_presence-d007} could not serialize access due to concurrent delete
 0/5
2024-02-23 22:10:19,911 - synapse.storage.txn - 737 - WARNING - GET-33605- [TXN OPERROR] {update_presence-d031} could not serialize access due to concurrent delete
 0/5
2024-02-23 22:10:21,065 - synapse.storage.txn - 737 - WARNING - GET-33727- [TXN OPERROR] {update_presence-d0f7} could not serialize access due to concurrent delete
 0/5
2024-02-23 22:10:21,642 - synapse.storage.txn - 737 - WARNING - GET-33787- [TXN OPERROR] {update_presence-d157} could not serialize access due to concurrent delete
 0/5
2024-02-23 22:10:22,506 - synapse.storage.txn - 737 - WARNING - GET-33877- [TXN OPERROR] {update_presence-d1f0} could not serialize access due to concurrent delete
 0/5
2024-02-23 22:10:23,067 - synapse.storage.txn - 737 - WARNING - GET-33946- [TXN OPERROR] {update_presence-d259} could not serialize access due to concurrent delete
 0/5
2024-02-23 22:10:24,507 - synapse.storage.txn - 737 - WARNING - GET-34086- [TXN OPERROR] {update_presence-d320} could not serialize access due to concurrent delete
 0/5
2024-02-23 22:10:24,804 - synapse.storage.txn - 737 - WARNING - GET-34112- [TXN OPERROR] {update_presence-d34a} could not serialize access due to concurrent delete
 0/5
2024-02-23 22:10:25,670 - synapse.storage.txn - 737 - WARNING - GET-34191- [TXN OPERROR] {update_presence-d3c8} could not serialize access due to concurrent delete
 0/5
2024-02-23 22:10:26,526 - synapse.storage.txn - 737 - WARNING - GET-34282- [TXN OPERROR] {update_presence-d464} could not serialize access due to concurrent delete
 0/5
2024-02-23 22:10:27,112 - synapse.storage.txn - 737 - WARNING - GET-34341- [TXN OPERROR] {update_presence-d4b4} could not serialize access due to concurrent delete
 0/5
2024-02-23 22:10:27,405 - synapse.storage.txn - 737 - WARNING - GET-34369- [TXN OPERROR] {update_presence-d4df} could not serialize access due to concurrent delete
 0/5
2024-02-23 22:10:28,278 - synapse.storage.txn - 737 - WARNING - GET-34447- [TXN OPERROR] {update_presence-d557} could not serialize access due to concurrent delete
 0/5
2024-02-23 22:10:28,865 - synapse.storage.txn - 737 - WARNING - GET-34504- [TXN OPERROR] {update_presence-d5ca} could not serialize access due to concurrent delete
 0/5
2024-02-23 22:10:29,433 - synapse.storage.txn - 737 - WARNING - GET-34567- [TXN OPERROR] {update_presence-d61b} could not serialize access due to concurrent delete

As you can see, the warning is occurring about once per second. I suppose it is only a "WARNING", but I fear there is something wrong considering the volume of messages and the fact in involves transactions (deletes at that). Any idea what is going on?