Re: Cleanup: Duplicated, misplaced comment in HeapScanDescData

Hi,

On 2022-11-21 12:34:12 +0100, Matthias van de Meent wrote:
> On Mon, 21 Nov 2022 at 12:12, Matthias van de Meent
> <boekewurm+postgres@gmail.com> wrote:
> >
> > Hi,
> >
> > I noticed that the comment on/beneath rs_numblocks in HeapScanDescData
> > is duplicated above rs_strategy. I don't know if there should have
> > been a different comment above rs_strategy, but the current one is
> > definitely out of place, so I propose to remove it as per attached.
> >
> > The comment was duplicated in c2fe139c20 with the update to the table
> > scan APIs, which was first seen in PostgreSQL 11.
> 
> I made a mistake in determining this version number; it was PostgreSQL
> 12 where this commit was first included. Attached is the same patch
> with the description updated accordingly.

I guess that happened because of the odd placement of the comment from
before the change:

     bool        rs_temp_snap;   /* unregister snapshot at scan end? */
-
-    /* state set up at initscan time */
-    BlockNumber rs_nblocks;     /* total number of blocks in rel */
-    BlockNumber rs_startblock;  /* block # to start at */
-    BlockNumber rs_numblocks;   /* max number of blocks to scan */
-    /* rs_numblocks is usually InvalidBlockNumber, meaning "scan whole rel" */
-    BufferAccessStrategy rs_strategy;   /* access strategy for reads */
     bool        rs_syncscan;    /* report location to syncscan logic? */

We rarely put comments document a struct member after it.

I'm inclined to additionally move the "legitimate" copy of the comment
to before rs_numblocks, rather than after it.

Greetings,

Andres Freund