From: Jonathan Corbet <corbet@lwn.net>
To: meta@public-inbox.org
Subject: SQLite, UPDATE, and LIMIT
Date: Thu, 22 Feb 2018 16:14:14 -0700 [thread overview]
Message-ID: <20180222161414.24d305f1@lwn.net> (raw)
So I'm messing with public-inbox a bit. I had to make the following
change before things would work on my Fedora system. (This is with
v1.0.0).
The symptom was errors out of SQLite; it wouldn't pass "make test" much
less work properly. Some digging turns up this:
If SQLite is built with the SQLITE_ENABLE_UPDATE_DELETE_LIMIT
compile-time option then the syntax of the UPDATE statement is
extended with optional ORDER BY and LIMIT clauses as follows
Evidently, Fedora does not enable that option.
Now, I assume that LIMIT is there for a reason; I've not even tried to
look at the schema that public-inbox uses yet. But I thought I would toss
this out there to see you thought. Perhaps what I really need to do is to
ask Fedora to turn that option on?
Thanks,
jon
From f0d6f3771013fadbeb8432533d51545696309ffb Mon Sep 17 00:00:00 2001
From: Jonathan Corbet <corbet@pi.lwn.net>
Date: Thu, 22 Feb 2018 23:05:46 +0000
Subject: [PATCH] Don't use LIMIT in UPDATE statements
...not all distributions build SQLite with that enabled.
---
lib/PublicInbox/Msgmap.pm | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/PublicInbox/Msgmap.pm b/lib/PublicInbox/Msgmap.pm
index a147b9f..6b6d1c6 100644
--- a/lib/PublicInbox/Msgmap.pm
+++ b/lib/PublicInbox/Msgmap.pm
@@ -57,7 +57,7 @@ sub meta_accessor {
$prev = $dbh->selectrow_array($sql, undef, $key);
if (defined $prev) {
- $sql = 'UPDATE meta SET val = ? WHERE key = ? LIMIT 1';
+ $sql = 'UPDATE meta SET val = ? WHERE key = ?';
$dbh->do($sql, undef, $value, $key);
} else {
$sql = 'INSERT INTO meta (key,val) VALUES (?,?)';
--
2.14.3
next reply other threads:[~2018-02-22 23:14 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-22 23:14 Jonathan Corbet [this message]
2018-02-22 23:24 ` SQLite, UPDATE, and LIMIT Eric Wong
2018-02-22 23:28 ` Jonathan Corbet
2018-02-22 23:33 ` Eric Wong
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