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.
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There are two areas that needed to be updated to support this: building the archive-get queue and checking that WAL has been archived after a backup.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.
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.
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.
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.
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.
The existing static files would not work with 32-bit or big-endian systems so create functions to generate these files dynamically rather than creating a bunch of new static files.
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.
Previously, functions with sensitive options had to be logged at trace level to avoid exposing them. Trace level logging may still expose secrets so use with caution.
