RE: Slow catchup of 2PC (twophase) transactions on replica in LR

Dear Hou, Peter,

Thanks for giving comments! PSA new version.
Almost comments were addressed.
What's new:
0001 - IsTwoPhaseTransactionGidForSubid() was updated per comment from Hou-san [1].
          Some nitpicks were accepted.
0002 - An argument in CheckAlterSubOption() was renamed to " slot_needs_update "
          Some nitpicks were accepted.
0003 - Some nitpicks were accepted.

Below part contains the reason why I rejected some comments.

> CommonChecksForFailoverAndTwophase:
> nitpick - added Assert for the generic-looking "option" parameter name

The style looks strange for me, using multiple strcmp() is more straightforward.
Added like that.

> 1c.
> If the error checks can be moved to be done up-front, then all the 'needs_update'
> can be combined. Avoiding multiple checks to 'needs_update' will make this function simpler.

This style was needed to preserve error condition for failover option. Not changed.

[1]:
https://www.postgresql.org/message-id/OS3PR01MB571834FBD3E6D3804484038F94A32%40OS3PR01MB5718.jpnprd01.prod.outlook.com

Best regards,
Hayato Kuroda
FUJITSU LIMITED