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.
The C code was warning on failure and continuing but the Perl logging code was never updated with the same feature.
Rather than add the feature to Perl, just disable file logging if the log file cannot be opened. Log files are always opened by C first, so this will eliminate the error in Perl.
Reported by vthriller.
This test has been flapping since 9b9396c7. It seems to be some kind of timing issue since all integration tests pass and this unit passes on all other VMs. It only happens on Travis and is not reproducible in any development environment that we have tried.
For now, disable the test since the constant flapping is causing major delays in testing and quite a bit of time has been spent trying to identify the root cause. We are actively developing these tests and hope the issue will be identified during the course of normal development.
A number of improvements were made to the tests while searching for this issue. While none of them helped, it makes sense to keep the improvements.
There doesn't seem to be any need to implement this as a filter since current use cases (S3 authentication) work on small datasets.
So, use the single function method provided by OpenSSL for simplicity.
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There are two areas that needed to be updated to support this: building the archive-get queue and checking that WAL has been archived after a backup.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.
As we add storage drivers it's important to keep the tests for each completely separate. Rather than have three tests for each driver, standardize on having a single test unit for each driver.
These are separated the same way in the Perl code where the remote storage driver is located in the Protocol module. However, in the C code the intention is to implement the remote storage driver as a regular driver in the storage layer rather than making a special case out of it.
So, merge the storage helpers. This also has the benefit of making the code a bit simpler.
Also separate storageSpool() and storageSpoolWrite() to make it clearer which operations require write access and to maintain consistency with the other storage helper functions.
The posix driver was developed over time and the naming is not very consistent.
Rename the files and functions to work well with other drivers and generally favor longer names since the driver functions are seldom (eventually never) used outside the driver itself.
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.
Basic functions to detect the presence of stanza or all stop files and error when they are present.
The functionality to detect stop files without error was not migrated. This functionality is only used by stanza-delete and will be migrated with that command.
Implement rules for generating paths within the archive part of the repository. Add a helper function, storageRepo(), to create the repository storage based on configuration settings.
The repository storage helper is located in the protocol module because it will support remote file systems in the future, just as the Perl version does.
Also, improve the existing helper functions a bit using string functions that were not available when they were written.
Use JSON code now that it is available and remove temporary hacks used to get things working initially.
Use passed storage objects rather than using storageLocal(). All storage objects in C are still local but this won't always be the case.
Also, move Postgres version conversion functions to postgres/info.c since they have no dependency on the info objects and will likely be useful elsewhere.
common/harnessLog was not ideally suited for general testing and made all the tests quite awkward. Instead, move all code used to test the common/log module into the logTest module and repurpose common/harnessLog to do log expect testing for all other tests in a cleaner way.
Add a few exceptions for config testing since the log levels are reset by default in config/parse.
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.
Many options that were set per test can instead be inferred from the types, i.e. container, c, expect, and individual.
Also finish renaming Perl unit tests with the -perl suffix.
* Add storageCopy(), storageMove(), and storagePathSync().
* Separate StorageFile object into separate read and write objects.
* Abstract out Posix file read/write objects.
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.
This implementation should be faster because it does not stat each file. It simply assumes that most directory entries are files so attempts an unlink() first. If the entry is reported by error codes to be a directory then it attempts an rmdir().
