Add macros for ReorderBufferTXN toptxn - Mailing list pgsql-hackers

From Peter Smith
Subject Add macros for ReorderBufferTXN toptxn
Date
Msg-id CAHut+PuCznOyTqBQwjRUu-ibG-=KHyCv-0FTcWQtZUdR88umfg@mail.gmail.com
Whole thread Raw
Responses Re: Add macros for ReorderBufferTXN toptxn
Re: Add macros for ReorderBufferTXN toptxn
List pgsql-hackers
Hi,

During a recent code review, I was confused multiple times by the
toptxn member of ReorderBufferTXN, which is defined only for
sub-transactions.

e.g. txn->toptxn member == NULL means the txn is a top level txn.
e.g. txn->toptxn member != NULL means the txn is not a top level txn

It makes sense if you squint and read it slowly enough, but IMO it's
too easy to accidentally misinterpret the meaning when reading code
that uses this member.

~

Such code can be made easier to read just by introducing some simple macros:

#define isa_toptxn(rbtxn) (rbtxn->toptxn == NULL)
#define isa_subtxn(rbtxn) (rbtxn->toptxn != NULL)
#define get_toptxn(rbtxn) (isa_subtxn(rbtxn) ? rbtxn->toptxn : rbtxn)

~

PSA a small patch that does this.

(Tests OK using make check-world)

Thoughts?

------
Kind Regards,
Peter Smith.
Fujitsu Australia

Attachment

pgsql-hackers by date:

Previous
From: Melanie Plageman
Date:
Subject: Re: Sub-millisecond [autovacuum_]vacuum_cost_delay broken
Next
From: Juan José Santamaría Flecha
Date:
Subject: Re: pg_dump/pg_restore: Fix stdin/stdout handling of custom format on Win32