Mercurial > p > roundup > code
comparison doc/upgrading.txt @ 6930:a96a239db0d9
Set all sqlite db's to WAL mode on creation
Complete work done on 6917:fba76e0bba98.
WAL journaling mode now enabled on primary db as well as session db's
when using sqlite for session databases.
Made change to WAL mode more robust for testing by bracketing
`pragma journal_mode=wal` with commit() calls. Normally the conversion
would occur when a new session was opened, but this commits the changes
explicitly to make all the tests stable.
Also added doc on this.
| author | John Rouillard <rouilj@ieee.org> |
|---|---|
| date | Thu, 08 Sep 2022 01:12:12 -0400 |
| parents | 1319ab13f286 |
| children | bd2c3b2010c3 |
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| 6929:581b09777eba | 6930:a96a239db0d9 |
|---|---|
| 121 Session Databases`_ in the `administration guide`_ | 121 Session Databases`_ in the `administration guide`_ |
| 122 | 122 |
| 123 | 123 |
| 124 .. _Using Redis for Session Databases: | 124 .. _Using Redis for Session Databases: |
| 125 admin_guide.html#using-redis-for-session-databases | 125 admin_guide.html#using-redis-for-session-databases |
| 126 | |
| 127 New SQLite databases created with WAL mode journaling (optional) | |
| 128 ---------------------------------------------------------------- | |
| 129 | |
| 130 By default, SQLite databases use a rollback journal when | |
| 131 writing an update. The rollback journal stores a copy of the | |
| 132 data from before the update. One downside of this is that | |
| 133 all reads have to be suspended while a write is | |
| 134 occurring. SQLite has an alternate way of insuring ACID | |
| 135 compliance by using a WAL (write ahead log) journal. | |
| 136 | |
| 137 Version 2.3.0 of Roundup, creates new SQLite databases using | |
| 138 WAL journaling. With WAL, a writer does not block readers | |
| 139 and readers do not block writing an update. This keeps | |
| 140 Roundup accessible even under a heavy write load (e.g. when | |
| 141 bulk loading data or automated updates via REST). | |
| 142 | |
| 143 If you want to convert your existing SQLite db to WAL mode: | |
| 144 | |
| 145 1. check the current journal mode on your database | |
| 146 using:: | |
| 147 | |
| 148 sqlite3 <tracker_home>/db/db "pragma journal_mode;" | |
| 149 | |
| 150 2. If it returns ``delete``, change it to WAL mode using:: | |
| 151 | |
| 152 sqlite3 <tracker_home>/db/db "pragma journal_mode=WAL;" | |
| 153 | |
| 154 3. verify by running the command in step 1 again and you | |
| 155 should get ``wal``. | |
| 156 | |
| 157 If you are using SQLite for session and otk databases, | |
| 158 perform the same steps replacing ``db`` with ``db-session`` | |
| 159 and ``db-otk``. | |
| 160 | |
| 161 If you find WAL mode is not working for you, you can set the | |
| 162 journal method to a rollback journal (``delete`` mode) by | |
| 163 using step 2 and replacing ``wal`` with ``delete``. (Note: | |
| 164 SQLite supports other journaling modes, but only ``wal`` and | |
| 165 ``delete`` persist. Roundup doesn't set a journaling mode | |
| 166 when it opens the database, so options such as ``truncate`` | |
| 167 are not used.) | |
| 168 | |
| 169 For details on WAL mode see `<https://www.sqlite.org/wal.html>`_ | |
| 170 and `<https://www.sqlite.org/pragma.html#pragma_journal_mode>`_. | |
| 126 | 171 |
| 127 .. index:: Upgrading; 2.1.0 to 2.2.0 | 172 .. index:: Upgrading; 2.1.0 to 2.2.0 |
| 128 | 173 |
| 129 Migrating from 2.1.0 to 2.2.0 | 174 Migrating from 2.1.0 to 2.2.0 |
| 130 ============================= | 175 ============================= |