Define variables in the approprieate scope
I've noticed that two variables in RelationCopyStorage() are defined in a
scope higher than necessary. Please see the patch.
--
Antonin Houska
Web: https://www.cybertec-postgresql.com
Attachments:
variable_scope.patchtext/x-diffDownload
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index fddfbf1d8c..14d170823f 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -336,15 +336,11 @@ void
RelationCopyStorage(SMgrRelation src, SMgrRelation dst,
ForkNumber forkNum, char relpersistence)
{
- PGAlignedBlock buf;
- Page page;
bool use_wal;
bool copying_initfork;
BlockNumber nblocks;
BlockNumber blkno;
- page = (Page) buf.data;
-
/*
* The init fork for an unlogged relation in many respects has to be
* treated the same as normal relation, changes need to be WAL logged and
@@ -364,6 +360,9 @@ RelationCopyStorage(SMgrRelation src, SMgrRelation dst,
for (blkno = 0; blkno < nblocks; blkno++)
{
+ PGAlignedBlock buf;
+ Page page = (Page) buf.data;
+
/* If we got a cancel signal during the copy of the data, quit */
CHECK_FOR_INTERRUPTS();
On Tue, Feb 25, 2020 at 09:35:52AM +0100, Antonin Houska wrote:
I've noticed that two variables in RelationCopyStorage() are defined in a
scope higher than necessary. Please see the patch.
It seems cleaner to me to allocate the variables once before the loop
starts, rather than for each loop iteration.
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EnterpriseDB https://enterprisedb.com
+ As you are, so once was I. As I am, so you will be. +
+ Ancient Roman grave inscription +
On 2020-Mar-18, Bruce Momjian wrote:
On Tue, Feb 25, 2020 at 09:35:52AM +0100, Antonin Houska wrote:
I've noticed that two variables in RelationCopyStorage() are defined in a
scope higher than necessary. Please see the patch.It seems cleaner to me to allocate the variables once before the loop
starts, rather than for each loop iteration.
If we're talking about personal preference, my own is what Antonin
shows. However, since disagreement has been expressed, I think we
should only change it if the generated code turns out better.
--
�lvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
On Mon, Mar 23, 2020 at 01:00:24PM -0300, Alvaro Herrera wrote:
On 2020-Mar-18, Bruce Momjian wrote:
On Tue, Feb 25, 2020 at 09:35:52AM +0100, Antonin Houska wrote:
I've noticed that two variables in RelationCopyStorage() are defined in a
scope higher than necessary. Please see the patch.It seems cleaner to me to allocate the variables once before the loop
starts, rather than for each loop iteration.If we're talking about personal preference, my own is what Antonin
shows. However, since disagreement has been expressed, I think we
should only change it if the generated code turns out better.
I am fine with either usage, frankly. I was just pointing out what
might be the benefit of the current coding.
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EnterpriseDB https://enterprisedb.com
+ As you are, so once was I. As I am, so you will be. +
+ Ancient Roman grave inscription +
On Mon, Mar 23, 2020 at 08:50:55PM -0400, Bruce Momjian wrote:
On Mon, Mar 23, 2020 at 01:00:24PM -0300, Alvaro Herrera wrote:
If we're talking about personal preference, my own is what Antonin
shows. However, since disagreement has been expressed, I think we
should only change it if the generated code turns out better.I am fine with either usage, frankly. I was just pointing out what
might be the benefit of the current coding.
Personal opinion here. I tend to prefer putting variable declarations
into the inner portions because it makes it easier to reason about the
code, though I agree that this concept does not need to be applied all
the time.
--
Michael
Michael Paquier <michael@paquier.xyz> writes:
On Mon, Mar 23, 2020 at 08:50:55PM -0400, Bruce Momjian wrote:
I am fine with either usage, frankly. I was just pointing out what
might be the benefit of the current coding.
Personal opinion here. I tend to prefer putting variable declarations
into the inner portions because it makes it easier to reason about the
code, though I agree that this concept does not need to be applied all
the time.
My vote is to not make this sort of change until there's another
reason to touch the code in question. All changes create hazards for
back-patching, and I don't think this change is worth it on its own.
But if there are going to be diffs in the immediate vicinity anyway,
then sure.
(I'm feeling a bit sensitized to this, perhaps, because of recent
unpleasant experience with back-patching b4570d33a. That didn't touch
very much code, and the functions in question seemed like fairly stagnant
backwaters of the code base, so it should not have been painful to
back-patch ... but it was, because of assorted often-cosmetic changes
in said code.)
regards, tom lane