On 3/4/26 23:19, Fujii Masao wrote:
On Thu, Mar 5, 2026 at 12:41 AM Fujii Masao <[email protected]> wrote:
My earlier comment was based on my misunderstanding. I thought that only
32-bit transaction IDs were allowed for recovery_target_xid, and therefore
values larger than 2^32 should be rejected.
However, recovery_target_xid currently accepts both 32-bit XIDs and 64-bit
full transaction IDs (epoch + 32-bit XID). When a 64-bit value is specified,
only the 32-bit XID portion is used as the recovery target.
Given this behavior, your change seems to make sense.
I'm tempted to clarify this behavior by adding something like
the following text to the description of recovery_target_xid
in config.sgml...:
-------------------------------
The value can be specified as either a 32-bit transaction ID or a 64-bit
transaction ID (consisting of an epoch and a 32-bit ID), such as the value
returned by pg_current_xact_id(). When a 64-bit transaction ID is provided,
only its 32-bit transaction ID portion is used as the recovery target.
For example, the values 4294968296 (epoch 1) and 8589935592 (epoch 2)
both refer to the same 32-bit transaction ID, 1000.
The effective transaction ID (the 32-bit portion) must be greater than
or equal to 3.
-------------------------------
+1. I added this to the v3 patch.
Regards,
-David
