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Diffstat (limited to 'scripts/migration/0.8.2/README.md')
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diff --git a/scripts/migration/0.8.2/README.md b/scripts/migration/0.8.2/README.md new file mode 100644 index 00000000..919a5235 --- /dev/null +++ b/scripts/migration/0.8.2/README.md @@ -0,0 +1,73 @@ +CouchDB schema migration to Soledad 0.8.2 +========================================= + +Migrate couch database schema from <= 0.8.1 version to 0.8.2 version. + + +ATTENTION! +---------- + + - This script does not backup your data for you. Make sure you have a backup + copy of your databases before running this script! + + - Make sure you turn off any service that might be writing to the couch + database before running this script. + + +Usage +----- + +To see what the script would do, run: + + ./migrate.py + +To actually run the migration, add the --do-migrate command line option: + + ./migrate.py --do-migrate + +See command line options: + + ./migrate.py --help + + +Log +--- + +If you don't pass a --log-file command line option, a log will be written to +the `log/` folder. + + +Differences between old and new couch schema +-------------------------------------------- + +The differences between old and new schemas are: + + - Transaction metadata was previously stored inside each document, and we + used design doc view/list functions to retrieve that information. Now, + transaction metadata is stored in documents with special ids + (gen-0000000001 to gen-9999999999). + + - Database replica config metadata was stored in a document called + "u1db_config", and now we store it in the "_local/config" document. + + - Sync metadata was previously stored in documents with id + "u1db_sync_<source-replica-id>", and now are stored in + "_local/sync_<source-replica-id>". + + - The new schema doesn't make use of any design documents. + + +What does this script do +------------------------ + +- List all databases starting with "user-". +- For each one, do: + - Check if it contains the old "u1db_config" document. + - If it doesn't, skip this db. + - Get the transaction log using the usual design doc view/list functions. + - Write a new "gen-X" document for each line on the transaction log. + - Get the "u1db_config" document, create a new one in "_local/config", + Delete the old one. + - List all "u1db_sync_X" documents, create new ones in "_local/sync_X", + delete the old ones. + - Delete unused design documents. |