Re: notmuch dump: taking write-lock to protect from concurrent (cronned) notmuch...

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+From: David Bremner <david@tethera.net>\r
+To: Mark Walters <markwalters1009@gmail.com>, Maarten Aertsen\r
+       <sagi-notmuch@rtsn.nl>, notmuch@notmuchmail.org\r
+Subject: Re: notmuch dump: taking write-lock to protect from concurrent\r
+       (cronned) notmuch new?\r
+In-Reply-To: <878upafegc.fsf@qmul.ac.uk>\r
+References: <20140606080354.28047.77393@kardo.rtsn.nl>\r
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+Date: Thu, 12 Jun 2014 19:56:34 -0300\r
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+Mark Walters <markwalters1009@gmail.com> writes:\r
+\r
+\r
+>> mjw1009 suggested to change NOTMUCH_DATABASE_MODE_READ_ONLY on line\r
+>> 215 of notmuch-dump.c to NOTMUCH_DATABASE_MODE_READ_WRITE\r
+>>\r
+>> I'm wondering if this hits enough people to motivate the addition of a\r
+>> command line switch (or perhaps even a change in default behaviour?)\r
+>\r
+> I think this is a clear bug but the fix is a little unclear. The above\r
+> fix works but it breaks one of the tests: "unicode message-ids" in\r
+> T150-tagging.sh.\r
+>\r
+> I think the problem is that it does \r
+> notmuch dump | sed... | notmuch restore\r
+>\r
+\r
+My first reaction was "argh, we should be locking things less, not\r
+more".  But then I read \r
+\r
+        http://getting-started-with-xapian.readthedocs.org/en/latest/xapian-core-rst/admin_notes.html?highlight=backup#id10\r
+\r
+and now I'm not so sure, maybe write lock for dump is the right answer.\r
+\r
+It seems hard to do anything sensible with "Database.reopen" in the\r
+context of a backup.\r
+\r
+\r