Horton

Re: Switching XLog source from archive to streaming when primary available

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Cc: Japin Li <japinli@hotmail.com>, Ian Lawrence Barwick <barwick@gmail.com>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, Cary Huang <cary.huang@highgo.ca>, SATYANARAYANA NARLAPURAM <satyanarlapuram@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2024-03-05T19:52:12Z
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. Add basic TAP tests for the low-level backup method, take two

  2. Add a failover option to subscriptions.

  3. Make all Perl warnings fatal

  4. Add PostgreSQL::Test::Cluster::advance_wal

  5. Rename wal_keep_segments to wal_keep_size.

On Tue, Mar 05, 2024 at 11:38:37PM +0530, Bharath Rupireddy wrote:
> On Tue, Mar 5, 2024 at 7:34 AM Nathan Bossart <nathandbossart@gmail.com> wrote:
>> Is there any way to simplify this?  For
>> example, would it be possible to make an enum that tracks the
>> streaming_replication_retry_interval state?
> 
> I guess the way it is right now looks simple IMHO. If the suggestion
> is to have an enum like below; it looks overkill for just two states.
> 
> typedef enum
> {
>     CAN_SWITCH_SOURCE,
>     SWITCH_SOURCE
> } XLogSourceSwitchState;

I was thinking of something more like

	typedef enum
	{
		NO_FORCE_SWITCH_TO_STREAMING,		/* no switch necessary */
		FORCE_SWITCH_TO_STREAMING_PENDING,	/* exhausting pg_wal */
		FORCE_SWITCH_TO_STREAMING,			/* switch to streaming now */
	} WALSourceSwitchState;

At least, that illustrates my mental model of the process here.  IMHO
that's easier to follow than two similarly-named bool variables.

-- 
Nathan Bossart
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