Previously setting compress-level-network=0 would disable compression. This worked because gzip disables compression at this level but still transmits the data in gz format.
lz4 does not provide similar functionality so we would need to disable the compression filter entirely. This does not seem worth it however since lz4 compression is very efficient and 0 is the default fast mode.
This backup method does a preliminary copy of all files that were last modified prior to a defined interval before calling pg_backup_start(). Then the backup is started as usual and the remainder of the files are copied. The advantage is that generally a smaller set of WAL will be required to make the backup consistent, provided there are some files that have not been recently modified.
The length of the prior full backup is used to determine the interval used for the preliminary copy since any files modified within this interval will likely be modified again during the backup. If no prior full backup exists then the interval is set to one day.
This feature is being committed as internal-only for the time being.
The integration tests could fail if:
1. After restoring the PostgreSQL instance the recovery process starts, which calls asynchronous archive-get.
2. After archive-get checks the existence of the queue directory, but before writing the WAL file, there are restores when the next test is begun, which leads to the deletion of the queue directory.
3. Since the directory no longer exists, writing the WAL file will fail, and archive-get will write the error file to the queue.
4. A new PostgreSQL instance will start and the recovery process will begin, which requests the WAL file.
5. The new archive-get looks into the queue directory, finds the error file, and throws out the error, after which the PostgreSQL recovery fails because the previous archive-get background process has not finished yet.
This patch fixes the problem by using a separate spool directory for each test.
8d6bceb5 refactored version/help to operate more like regular commands in part to simplify the implementation of --version and --help. Unfortunately this had the side effect of these commands also loading pgbackrest.conf which would lead to an error if the file could not be read or parsed.
Add a filter to prevent version or help from loading pgbackrest.conf. Also prevent reads from the env to stop any warnings or errors from that source.
Per our policy to support five EOL versions of PostgreSQL, 9.4 is no longer supported by pgBackRest. Remove all logic associated with 9.4 and update the tests.
This includes a small fix in infoPg.c to allow backup.info files with old versions to be saved. This allows expire to function when old versions are present. Even though those older versions cannot be used, they can be expired.
Tests for 9.4 are left in the expire/info tests to demonstrate that these commands work with old versions present.
