[PATCH] HACK: lib: add brute and ignorant handling of database lock errors

diff --git a/41/b01274da9acae510c3db192d4e54884dcfdbac b/41/b01274da9acae510c3db192d4e54884dcfdbac
new file mode 100644 (file)
index 0000000..d8fcd7a
--- /dev/null
+++ b/41/b01274da9acae510c3db192d4e54884dcfdbac
@@ -0,0 +1,116 @@
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+From: Jani Nikula <jani@nikula.org>\r
+To: notmuch@notmuchmail.org\r
+Subject: [PATCH] HACK: lib: add brute and ignorant handling of database lock\r
+       errors\r
+Date: Thu,  1 Jan 2015 20:22:03 +0200\r
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+\r
+From: Jani Nikula <jani.nikula@intel.com>\r
+\r
+Instead of failing at first try, back off for an increasing number of\r
+seconds, and only fail after three attempts.\r
+\r
+One of my notmuch installations that gets plenty of mail hits db\r
+locked exceptions quite often, and even more than before since I\r
+switched to using notmuch insert. These are quite annoying in the\r
+Emacs UI as there is virtually no error handling for tagging, and the\r
+tag change highlighting gets confused.\r
+\r
+This is a dirty hack, but for me it's much more preferrable to the the\r
+db locked exceptions. With the retries and increasing back-off timeout\r
+I hardly ever see the exceptions now.\r
+\r
+Maybe this inspires someone to fix this for real. ;)\r
+---\r
+ lib/database.cc | 19 +++++++++++++++++--\r
+ 1 file changed, 17 insertions(+), 2 deletions(-)\r
+\r
+diff --git a/lib/database.cc b/lib/database.cc\r
+index 3601f9ded307..50063c55969b 100644\r
+--- a/lib/database.cc\r
++++ b/lib/database.cc\r
+@@ -819,8 +819,23 @@ notmuch_database_open (const char *path,\r
+       string last_thread_id;\r
+ \r
+       if (mode == NOTMUCH_DATABASE_MODE_READ_WRITE) {\r
+-          notmuch->xapian_db = new Xapian::WritableDatabase (xapian_path,\r
+-                                                             Xapian::DB_CREATE_OR_OPEN);\r
++          /*\r
++           * Brute and ignorant handling of database lock errors.\r
++           * Instead of failing at first try, back off for an\r
++           * increasing number of seconds.\r
++           */\r
++          for (unsigned int tries = 1; ! notmuch->xapian_db; tries++) {\r
++              try {\r
++                  notmuch->xapian_db =\r
++                      new Xapian::WritableDatabase (xapian_path,\r
++                                                    Xapian::DB_CREATE_OR_OPEN);\r
++              } catch (const Xapian::DatabaseLockError &error) {\r
++                  if (tries > 3)\r
++                      throw;\r
++\r
++                  sleep(tries);\r
++              }\r
++          }\r
+       } else {\r
+           notmuch->xapian_db = new Xapian::Database (xapian_path);\r
+       }\r
+-- \r
+2.1.4\r
+\r