A weird bit in pg_upgrade/exec.c
Hello!
I've came across a weird bit in pg_upgrade/exec.c
We have a function check_bin_dir() which goes like this (old_cluster and
new_cluster are global variables):
void check_bin_dir(ClusterInfo *cluster)
{
...
get_bin_version(&old_cluster);
get_bin_version(&new_cluster);
...
}
This function has two calls:
check_bin_dir(&old_cluster);
check_bin_dir(&new_cluster);
I'd like to substitute these last two lines with this:
get_bin_version(cluster);
Doing it would simplify the patch I'm writing, but I'm worried I might
break something that's been there for a long time and has been working
fine. Is there maybe a reason for it to be this way that I don't happen
to understand?
Also, there's the exact same situation with the get_bin_version()
function in the same file.
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a.akenteva@postgrespro.ru wrote:
This function has two calls:
check_bin_dir(&old_cluster);
check_bin_dir(&new_cluster);I'd like to substitute these last two lines with this:
get_bin_version(cluster);
Odd indeed. One would think that if a cluster variable is passed as
parameter, the global vars should not be used. +1 for fixing it, and
your proposal sounds as good as any.
Doing it would simplify the patch I'm writing, but I'm worried I might break
something that's been there for a long time and has been working fine.
I think odd coding this was introduced recently because of the
pg_resetxlog -> pg_resetwal renaming.
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a.akenteva@postgrespro.ru writes:
I've came across a weird bit in pg_upgrade/exec.c
We have a function check_bin_dir() which goes like this (old_cluster and
new_cluster are global variables):
void check_bin_dir(ClusterInfo *cluster)
{
...
get_bin_version(&old_cluster);
get_bin_version(&new_cluster);
...
}
This function has two calls:
check_bin_dir(&old_cluster);
check_bin_dir(&new_cluster);
I'd like to substitute these last two lines with this:
get_bin_version(cluster);
Yeah, the way it is now seems outright broken. It will try to do
get_bin_version on the new cluster before having done validate_exec
there, violating its own comment.
I think we should change this as a bug fix, independently of whatever
else you had in mind to do here.
regards, tom lane
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Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
I think odd coding this was introduced recently because of the
pg_resetxlog -> pg_resetwal renaming.
Dunno about that, but certainly somebody fat-fingered a refactoring
there. The 9.6 code looks quite different but doesn't seem to be
doing anything silly.
regards, tom lane
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Tom Lane <tgl@sss.pgh.pa.us> writes:
Yeah, the way it is now seems outright broken. It will try to do
get_bin_version on the new cluster before having done validate_exec
there, violating its own comment.I think we should change this as a bug fix, independently of whatever
else you had in mind to do here.
I see this bug is now fixed in pg_upgrade/exec.c => check_bin_dir().
There's another bit exactly like that in check_data_dir() though.
We use global variables instead of using the argument passed to the
function,
which makes the function not reusable. Sorry if I mentioned it too
vaguely
in the previous letter.
I attached a patch with the change that would fix it.
In pg_upgrade/exec.c => check_data_dir() I substituted these two lines
old_cluster.major_version = get_major_server_version(&old_cluster);
new_cluster.major_version = get_major_server_version(&new_cluster);
with this line:
cluster->major_version = get_major_server_version(cluster);
and changed the comment accordingly.
Attachments:
Fixed-exec-c.patchtext/x-diff; name=Fixed-exec-c.patchDownload
From 9b63a7fc5d1dce6d254aec0abe412f2c1cd5f889 Mon Sep 17 00:00:00 2001
From: Akenteva Anna <a.akenteva@postgrespro.ru>
Date: Thu, 16 Nov 2017 13:25:29 +0300
Subject: [PATCH] Fixed check_data_dir in pg_upgrade/exec.c
Changed using global variables (old_cluster and new_cluster) into
using the argument of the check_data_dir function.
---
src/bin/pg_upgrade/exec.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/src/bin/pg_upgrade/exec.c b/src/bin/pg_upgrade/exec.c
index 810a5a0..f5cd74f 100644
--- a/src/bin/pg_upgrade/exec.c
+++ b/src/bin/pg_upgrade/exec.c
@@ -331,9 +331,8 @@ check_data_dir(ClusterInfo *cluster)
{
const char *pg_data = cluster->pgdata;
- /* get old and new cluster versions */
- old_cluster.major_version = get_major_server_version(&old_cluster);
- new_cluster.major_version = get_major_server_version(&new_cluster);
+ /* get the cluster version */
+ cluster->major_version = get_major_server_version(cluster);
check_single_dir(pg_data, "");
check_single_dir(pg_data, "base");
--
2.7.4
a.akenteva@postgrespro.ru writes:
I see this bug is now fixed in pg_upgrade/exec.c => check_bin_dir().
There's another bit exactly like that in check_data_dir() though.
Oh, so there is ... and looking around, that seems to have been
copied-and-pasted out of check_cluster_versions(), without any
thought for the fact that those calls were thereby made redundant.
Fix pushed, thanks for noticing!
regards, tom lane