Thread: _bt_delitems_delete() should use XLogRegisterBufData(), not XLogRegisterData()

The RelationNeedsWAL() code block within _bt_delitems_delete() has had
the following comment for many years now:

/*
 * We need the target-offsets array whether or not we store the whole
 * buffer, to allow us to find the latestRemovedXid on a standby
 * server.
 */
XLogRegisterData((char *) itemnos, nitems * sizeof(OffsetNumber));

However, we don't actually need to do it that way these days. We won't
go on to determine a latestRemovedXid on a standby as of commit
558a9165e08 (that happens on the primary instead), so the comment
seems wrong.

Rather than just changing the comment, I propose that we tweak the
behavior of _bt_delitems_delete() to match its sibling function
_bt_delitems_vacuum(). That is, it should use XLogRegisterBufData(),
not XLogRegisterData(). This is cleaner, and ought to be a minor win.

Attached patch shows what I have in mind. The new comment block has
been copied from _bt_delitems_vacuum().

--
Peter Geoghegan

On Wed, Jan 1, 2020 at 1:00 PM Peter Geoghegan <pg@bowt.ie> wrote:
> Attached patch shows what I have in mind. The new comment block has
> been copied from _bt_delitems_vacuum().

I also think that the WAL record and function signature of
_bt_delitems_delete() should be brought closer to
_bt_delitems_vacuum(). Attached patch does it that way.

I intend to commit this in the next day or two, barring any objections.

-- 
Peter Geoghegan