SQLite, UPDATE, and LIMIT

[Jonathan Corbet <corbet@lwn.net>]

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