Allow buffers to report a lower size than their allocated size. This means a larger buffer can be used to do the work of a smaller buffer without having to create a new buffer and concatenate.
This is useful for blocking I/O where the buffer may be too large for the amount of data that is available to read.
There are a number of cases where a checksum delta is more appropriate than the default time-based delta:
* Timeline has switched since the prior backup
* File timestamp is older than recorded in the prior backup
* File size changed but timestamp did not
* File timestamp is in the future compared to the start of the backup
* Online option has changed since the prior backup
A practical example is that checksum delta will be enabled after a failover to standby due to the timeline switch. In this case, timestamps can't be trusted and our recommendation has been to run a full backup, which can impact the retention schedule and requires manual intervention.
Now, a checksum delta will be performed if the backup type is incr/diff. This means more CPU will be used during the backup but the backup size will be smaller and the retention schedule will not be impacted.
Contributed by Cynthia Shang.
If an error occurred while acquiring a lock on a remote server the error would be reported correctly, but the queue max detection code was not reached. The tests failed to detect this because they fixed the connection before queue max, allowing the ccde to be reached.
Move the queue max code before the lock so it will run even when remote connections are not working. This means that no attempt will be made to transfer WAL once queue max has been exceeded, but it makes it much more likely that the code will be reach without error.
Update tests to continue errors up to the point where queue max is exceeded.
Reported by Lardière Sébastien.
The InfoPg object was partially modified in 960ad732 to place the current history item in position 0, but infoPgDataCurrent() didn't get updated correctly.
Remove this->indexCurrent and make the current position always equal 0. Use the new lstInsert() function when adding new history items via infoPgAdd(), but continue to use lstAdd() when loading from a file for efficiency.
This does not appear to be a live bug because infoPgDataCurrent() and infoPgAdd() are not yet used in any production code. The archive-get command is the only C code using InfoPG and it always looks at the entire list of items rather than just the current item.
Suggested by Cynthia Shang.
PostgreSQL 11 introduces configurable WAL segment sizes, from 1MB to 1GB.
There are two areas that needed to be updated to support this: building the archive-get queue and checking that WAL has been archived after a backup. Both operations require the WAL segment size to properly build a list.
Checking the archive after a backup is still implemented in Perl and has an active database connection, so just get the WAL segment size from the database.
The archive-get command does not have a connection to the database, so get the WAL segment size from pg_control instead. This requires a deeper inspection of pg_control than has been done in the past, so it seemed best to copy the relevant data structures from each version of PostgreSQL and build a generic interface layer to address them. While this approach is a bit verbose, it has the advantage of being relatively simple, and can easily be updated for new versions of PostgreSQL.
Since the integration tests generate pg_control files for testing, teach Perl how to generate files with the correct offsets for both 32-bit and 64-bit architectures.
Use checksums rather than timestamps to determine if files have changed. This is useful in cases where the timestamps may not be trustworthy, e.g. when performing an incremental after failing over to a standby.
If checksum delta is enabled then checksums will be used for verification of resumed backups, even if they are full. Resumes have always used checksums to verify the files in the repository, enabling delta performs checksums on the database files as well.
Note that the user must manually enable this feature in cases were it would be useful or just keep in enabled all the time. A future commit will address automatically enabling the feature in cases where it seems likely to be useful.
Contributed by Cynthia Shang.
Apparently we never needed to run this function remotely.
It will be needed by the backup checksum delta feature, so implement it now.
Contributed by Cynthia Shang.
For read-only repositories the Posix and CIFS drivers behave exactly the same. Since that's all we support in C right now it's valid to treat them as the same thing. An assertion has been added to remind us to add the CIFS driver before allowing the repository to be writable.
Mostly we want to make sure that the C code does not blow up when the repository type is CIFS.
The external storage interfaces (Storage, StorageFileRead, etc.) have been stable for a while, but internally they were calling the posix driver functions directly.
Create driver interfaces for storage, fileRead, and fileWrite and remove all references to the posix driver outside storage/driver/posix (with the exception of a direct call to pathRemove() in Perl LibC).
Posix is still the only available driver so more adjustment may be needed, but this should represent the bulk of the changes.
Previously, debug log functions had to handle NULLs and truncate output to the available buffer size. This was verbose for both coding and testing.
Instead, create a function/macro combination that allows log functions to return a simple String object. The wrapper function takes care of the memory context, handles NULLs, and truncates the log string based on the available buffer size.
The archive-get command will only be executed in C if the repository is local, unencrypted, and type posix or cifs. Admittedly a limited use case, but this is just the first step in migrating the archive-get command entirely into C.
This is a direct migration from the Perl code (including messages) to integrate as seamlessly with the remaining Perl code as possible. It should not be possible to determine if the C version is running unless debug-level logging is enabled.
The info messages were spread around and logged differently based on the execution path and in some cases logged nothing at all.
Temporarily track the async server status with a flag so that info messages are not output in the async process. The async process will be refactored as a separate command to be exec'd in a future commit.
% characters caused issues in backup/restore due to filenames being appended directly into a format string.
Reserved XML characters (<>&') caused issues in the S3 driver due to improper escaping.
Add a file with all common special characters to regression testing.
The new archive-get C code can't run (yet) when encryption is enabled. Therefore move the encryption tests so we can test the new C code. We'll move it back when encryption is enabled in C.
Also, push one WAL segment with compression to test decompression in the C code.
A return code of 1 from the archive-get was being logged as an error message at info level but otherwise worked correctly.
Also improve info messages when an archive segment is or is not found.
Previously an error would be generated if other files were present and not owned by the PostgreSQL user. This hasn't been a big deal in practice but it could cause issues.
Also add tests to make sure the same logic applies with links to files, i.e. all other files in the directory should be ignored. This was actually working correctly, but there were no tests for it before.
The log-subprocess feature added in 22765670 failed to take into account the naming for remote processes spawned by local processes. Not only was the local command used for the naming of log files but the process id was not pass through. This meant every remote log was named "[stanza]-local-remote-000" which is confusing and meant multiple processes were writing to the same log.
Instead, pass the real command and process id to the remote. This required a minor change in locking to ignore locks if process id is greater than 0 since remotes started by locals never lock.
Relative link paths were being combined with the paths of previous links (relative or absolute) due to the $strPath variable being modified in the current iteration rather than simply being passed to the next level of recursion.
This issue did not affect absolute links and relative tablespace links were caught by other checks, though the error was confusing.
Reported by Cynthia Shang.
Implemented using the same logic as the patches adding this feature to PostgreSQL, 8694cc96 and 920a5e50. Temporary relation exclusion is enabled in PostgreSQL ≥ 9.0. Unlogged relation exclusion is enabled in PostgreSQL ≥ 9.1, where the feature was introduced.
Contributed by Cynthia Shang.
A regression in v0.82 removed the timestamp comparison when deciding which files from the aborted backup to keep on resume. All resumed backups should be considered inconsistent. A resumed backup can be identified by checking the log for the message "aborted backup of same type exists, will be cleaned to remove invalid files and resumed".
Reported by David Youatt, Yogesh Sharma, Stephen Frost.
Low-level functions only include stack trace in test builds while higher-level functions ship with stack trace built-in. Stack traces include all parameters passed to the function but production builds only create the parameter list when the log level is set high enough, i.e. debug or trace depending on the function.
pgBackRest currently has no way to request new credentials so the entire command (e.g. backup, restore) must complete before the credentials expire.
Contributed by Yogesh Sharma.
Configuration files are loaded from the directory specified by the --config-include-path option.
Add --config-path option for overriding the default base path of the --config and --config-include-path option.
Contributed by Cynthia Shang.
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.
Scanning the entire backup directory can be very expensive if there are a lot of small tables. The backup manifest contains the backup directory list so use it to perform syncs instead of scanning the backup directory.
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.
