The Perl process was exiting directly when called but that interfered with proper locking for the forked async process. Now Perl returns results to the C process which handles all errors, including signals.
Now only two types of locks can be taken: archive and backup. Most commands use one or the other but the stanza-* commands acquire both locks. This provides better protection than the old command-based locking scheme.
Move command begin to C except when it must be called after another command in Perl (e.g. expire after backup). Command begin logs correctly for complex data types like hash and list. Specify which commands will log to file immediately and set the default log level for log messages that are common to all commands. File logging is initiated from C.
After a stanza-upgrade it should still be possible to restore backups from the previous version and perform recovery with archive-get. However, archive-get only checked the most recent db version/id and failed.
Also clean up some issues when the same db version/id appears multiple times in the history.
Fixed by Cynthia Shang.
Reported by Clinton Adams.
Refactor storage layer to allow for new repository filesystems using drivers. (Reviewed by Cynthia Shang.)
Refactor IO layer to allow for new compression formats, checksum types, and other capabilities using filters. (Reviewed by Cynthia Shang.)
* Refactor Ini.pm to facilitate testing.
* Complete statement/branch coverage for Ini.pm.
* Improved functions used to test/munge manifest and info files.
* Fixed an issue where read-only operations that used local worker processes (i.e. restore) were creating write locks that could interfere with parallel archive-push. (Reported by Jens Wilke.)
* Simplify locking scheme. Now, only the master process will hold write locks (archive-push, backup) and not all the local and remote worker processes as before.
The stanza-upgrade command provides a mechanism for upgrading a stanza after upgrading to a new major version of PostgreSQL.
Contributed by Cynthia Shang.
