Currently errors found during the backup are only available in text output when specifying --set.
Add a flag to backup.info that is available in both the text and json output when --set is not specified. This at least provides the basic info that an error was found in the cluster during the backup, though details are still only available as described above.
Valgrind complained about uninitialized values on arm64 when comparing the reset prefix, probably because "reset" ended up being larger than the option name: Conditional jump or move depends on uninitialised value(s) at cfgParseOption (parse.c:568).
Coverity complained because it could not verify the size of the string to be copied into optionName, probably because it does not understand the purpose of strSize(): You might overrun the 65-character fixed-size string "optionName" by copying the return value of "strZ" without checking the length.
Use strncpy() even though we have already checked the size and make sure the string is terminated. Keep the size check because searching for truncated option names is not a good idea.
This is not a production bug since the code has not been released yet.
"error list" makes it clearer that other errors may be reported. For example, if checksum-page is true in the manifest but no checksum-page-error list is provided then the error is in alignment, i.e. the file size is not a multiple of the page size, with allowances made for a valid-looking partial page at the end of the file.
It is still not possible to differentiate between alignment and page checksum errors in the output but this will be addressed in a future commit.
Linefeeds were originally used in the place of <p> tags to denote a paragraph. While much of the linefeed usage has been replaced over time, there were many places where it was still being used, especially in reference.xml. This made it difficult to get consistent formatting across different output types. In particular there were formatting issues in the command-line help because it is harder to audit than HTML or PDF.
Replace linefeed formatting with proper <p> tags to make formatting more consistent.
Remove double spaces in all text where <p> tags were added since it does not add churn.
Update all <ul>/<ol>/<li> tags to the more general <list>/<list-item> tags.
Add a few missing periods.
The prior limitations were based on using getopt_long() to parse command-line options, which required a static list of allowed options. Setting index max too high bloated the binary unacceptably. 45a4e80 replaced the functionality of getopt_long() but the static list remained.
Improve cfgParseOption() to use available option data and remove the need for a static list. This also allows the option deprecations to be represented more compactly.
Index max is still capped at 256 because a large enough index could cause parseOptionIdxValue() to run out of memory since it allocates a static list based on the highest index found. If that function were improved with a map of found index values then index max could be set to UINT64_MAX.
Note that deprecations no longer set an index max or define whether reset is valid. These were space-saving measures which are no longer required. This means that indexed deprecated options will also be valid up to 256 and always allow reset, but it doesn't seem worth additional code to limit this behavior.
cfgParseOptionId() is no longer needed because calling cfgParseOption() with .ignoreMissingIndex = true duplicates the functionality of cfgParseOptionId(). This leads to some simplification in the help code.
IMPORTANT NOTE: The log level for copied files in the backup/restore commands has been changed to detail. This makes the info log level less noisy but if these messages are required then set the log level for the backup/restore commands to detail.
Bug Fixes:
* Detect errors in S3 multi-part upload finalize. (Reviewed by Cynthia Shang, Marco Montagna. Reported by Marco Montagna, Lev Kokotov, Anderson A. Mallmann.)
* Fix detection of circular symlinks. (Reviewed by Stefan Fercot. Reported by Rohit Raveendran.)
* Only pass selected repo options to the remote. (Reviewed by David Christensen, Cynthia Shang. Reported by Greg Sabino Mullane, David Christensen.)
Improvements:
* Binary protocol. (Reviewed by Cynthia Shang.)
* Automatically create data directory on restore. (Contributed by Stefan Fercot. Reviewed by David Steele. Suggested by Chris Bandy.)
* Allow restore --type=lsn. (Contributed by Stefan Fercot. Reviewed by Cynthia Shang. Suggested by James Coleman.)
* Change level of backup/restore copied file logging to detail. (Reviewed by Stefan Fercot. Suggested by Jens Wilke.)
* Loop while waiting for checkpoint LSN to reach replay LSN. (Contributed by Stefan Fercot. Reviewed by David Steele. Suggested by Fatih Mencutekin.)
* Log backup file total and restore size/file total. (Reviewed by Cynthia Shang.)
Documentation Bug Fixes:
* Fix incorrect host names in user guide. (Reviewed by Stefan Fercot. Reported by Greg Sabino Mullane.)
Documentation Improvements:
* Update contributing documentation and add pull request template. (Contributed by Cynthia Shang. Reviewed by David Steele.)
* Rearrange backup documentation in user guide. (Reviewed by Cynthia Shang.)
* Clarify restore --type behavior in command reference. (Contributed by Cynthia Shang. Reviewed by David Steele.)
* Fix documentation and comment typos. (Contributed by Eric Radman. Reviewed by David Steele.)
Test Suite Improvements:
* Add check for test path inside repo path. (Reviewed by Greg Sabino Mullane. Suggested by Greg Sabino Mullane.)
* Add CodeQL static code analysis. (Reviewed by Cynthia Shang.)
* Update tests to use standard patterns. (Contributed by Cynthia Shang. Reviewed by David Steele.)
Either of these temp mem context blocks fixes the issue of command packs not being freed, but it seems like a good idea to have both in case the code changes.
The backup size was a bit off because it did not include any files (e.g. backup_label, WAL files) that were added to the manifest after the main copy. To fix this move the log message to the very end of the backup.
Add size/file total log message to restore since it did not exist before.
Remove the "Automatic Stop Option" section since it only applies to PostgreSQL <= 9.6, which will soon be EOL. Since we no longer build the user guide for PostgreSQL < 10 this section was no longer being tested. The stop-auto option is still documented in the reference.
Move the "Fast Start Option" to "Quick Start - Perform Backup". This is a commonly-used option so it makes sense to mention it earlier. This also makes the backups run more quickly. In the worst case, backups in "Quick Start - Perform Backup" could take minutes to start
Move the "Archive Timeout" section to "Quick Start - Perform Backup" since it is the last section in "Backup".
The user and group were stored in a temp reset mem context so they could get freed if there were enough files to trigger the reset in storageRemoteInfoList().
Allocate user and group in a mem context provided by the caller to prevent them being freed prematurely.
Removed colon from example titles to fix links, fixed test.yml link, and updated the example for the parent/child test process to use the latest macros instead of sleep().
Additional buffers were being allocated for the protocol messages but not being freed.
Most of the allocations were fairly harness, but storageRemoteOpenReadProtocol() and storageWriteRemote() were problematic because they were allocating (but not freeing) buffers equal to the transfer size of the file. Depending on compression, this could be a lot of memory. Though the memory was freed after each file transfer the aggregate of memory used during parallel processing could overwhelm systems with constrained memory.
Also allocate larger initial buffers in storageRemoteOpenReadProtocol() and storageWriteRemote() so a reallocation is not needed.
Options for other repos can cause conflicts and should never be used. Each remote can address exactly one repo or pg cluster.
Also fix an outdated comment.
pg1 was incorrectly used instead of {[host-pg1]} which meant the wrong host name was displayed.
Also, the install block was installing packages to the build host no matter which host was specified.
If the test path is inside the repo path then it can cause strange issues during testing because the entire repo path is duplicated into the test path so that all tests see a consistent view of the repo.
Another solution might be to pick a better test path name and exclude it from the rsync, but this fix at least addresses the immediate issue.
The storage tests were not modified to the HRN_STORAGE_* nor TEST_STORAGE_* macros as these test are testing the storage drivers.
Note that posixTest.c removed an extraneous #endif // TEST_CONTAINER_REQUIRED and #ifdef TEST_CONTAINER_REQUIRED.
This PR includes all files in the storage/* test directory, namely: azureTest.c, cifsTest.c, gcsTest.c, posixTest.c, remoteTest.c, s3Test.c
Note that the logging output display of a parent/child test may look jumbled on some systems since the child and parent are attempting to log information at the same time. This is not an issue with the actual test, rather a harness issue that would be beyond the scope of this project to fix.
In the first test (helpRenderSplitSize) added test for empty list and in that and some other tests, the test comment was updated to clarify a bit more what the actual tests is trying to accomplish.
Note that help test parameters can only use the harnessConfig system when testing option values that have been set since options passed to the help command are not "set" options.
Includes backup and backupCommon tests.
Some tests in backupTest were split out where they were originally combined into a single boolean check - which made it difficult to determine which part of the conditional failed.
String values were also removed where they were no longer needed.
It is possible for the checkpoint LSN to lag slightly behind the replay LSN until pg_control has been updated.
Add a loop to keep checking rather than failing when the checkpoint LSN has not been updated.
The log level for copied files in the backup/restore commands has been changed to detail. This makes the info log level less noisy but if these messages are required then set the log level for the backup/restore commands to detail.
In the commandTest the HRN_STORAGE_REMOVE replacement uses .errorOnMissing when the code being tested added the file. The reason for this is 3 fold:
1. to ensure that an inadvertent typo in the path/file name does not go undetected,
2. to ensure that nothing else has removed the file prior to the call, and
3. consistency
Also, added "stanza" to comment when a stanza stop file is removed vs an "all" stop file.
Multi-part upload may fail despite returning an HTTP success code. Check for the ETag field in the result and if not present consider the upload to have failed. This will trigger a retry at the local job level.
Links were followed before they were checked for validity so a circular link would send the manifest build into endless recursion leading to a crash. Fix by moving the recursion after the link check.
Note that this issue has existed since the C migration and was not introduced by the refactor in eba013b.
Data directory creation was added during the C migration, but creation of the base data directory (PGDATA) was prevented by a check migrated from Perl.
Remove the check and update tests to create the data directory at least once.
Includes archiveCommon, archiveGet and archivePush.
Also fixed a test that was looking in repo instead of repo3 in the original archivePush to use the repo3 path as stated by the comment (line 879 in original tests and line 855 in new tests).
For tests already updated as part of the macro-replacement effort, the output tests (TEST_ERROR, TEST_RESULT_LOG, TEST_STORAGE_LIST and TEST_RESULT_STR) have been simplified for readability to remove all but the TEST_PATH constants. The ongoing macro-replacement effort will include these changes.
Updated: expireTest, stanzaTest, checkTest, infoTest, verifyTest (infoArchive and infoBackup had no changes).
Switch from JSON-based to binary protocol for communicating with local and remote process. The pack type is used to implement the binary protocol.
There are a number advantages:
* The pack type is more compact than JSON and are more efficient to render/parse.
* Packs are more strictly typed than JSON.
* Each protocol message is written entirely within ProtocolServer/ProtocolClient so is less likely to get interrupted by an error and leave the protocol in a bad state.
* There is no limit on message size. Previously this was limited by buffer size without a custom implementation, as was done for read/writing files.
Some cruft from the Perl days was removed, specifically allowing NULL messages and stack traces. This is no longer possible in C.
There is room for improvement here, in particular locking down the allowed sequence of protocol messages and building a state machine to enforce it. This will be useful for resetting the protocol when it gets in a bad state.
Some tests had to be reordered or updated, as follows:
* Reordered tests at line 317 and 331 to avoid unnecessary file removal.
* Change "stanza found" test at line 1735 to reflect real-life scenario. Originally this test had the cipher-pass environment key set up which caused the RepoGrp to be 2 but with no valid repo path. This resulted in the repo loops executing for the repo2 but since the path was not defined, the tests just reported "none" for cipher which is incorrect since the repo IS encrypted.
* Moved order of HRN_CFG_LOAD in some tests when able to avoid using storageTest.
It is better to clear errors after the catch block completes rather than leave them set until the next error. This also make is possible to tell when a error is currently being handled, which a function further down the stack might use to modify its behavior. Currently this is only useful in testing, but clearing the error seems like a good idea in general.
Two places used errors outside the CATCH() block. Mem context cleanup now uses a FINALLY() which is a better implementation anyway. The error handling in main() now calls exitSafe() from withing the CATCH() block.
Since the pack type was stored in 4 bits, only 15 values were allowed (0 was reserved).
Allow virtually unlimited types by storing type info in a base-128 encoded integer following the tag when the type bits in the tag are set to 0xF.
Also separate the type IDs used in the pack (PackTypeMap) from those presented to the user (PackType). The prior PackType enum exposed implementation details to the user, e.g. pckTypeUnknown.
Bug Fixes:
* Fix issues with leftover spool files from a prior restore. (Reviewed by Cynthia Shang, Stefan Fercot, Floris van Nee. Reported by Floris van Nee.)
* Fix issue when checking links for large numbers of tablespaces. (Reviewed by Cynthia Shang, Avinash Vallarapu. Reported by Avinash Vallarapu.)
* Free no longer needed remotes so they do not timeout during restore. (Reviewed by Cynthia Shang. Reported by Francisco Miguel Biete.)
* Fix help when a valid option is invalid for the specified command. (Reviewed by Stefan Fercot. Reported by Cynthia Shang.)
Features:
* Add PostgreSQL 14 support. (Reviewed by Cynthia Shang.)
* Add automatic GCS authentication for GCE instances. (Reviewed by Jan Wieck, Daniel Farina.)
* Add repo-retention-history option to expire backup history. (Contributed by Stefan Fercot. Reviewed by Cynthia Shang, David Steele.)
* Add db-exclude option. (Contributed by Stefan Fercot. Reviewed by Cynthia Shang.)
Improvements:
* Change archive expiration logging from detail to info level. (Contributed by Cynthia Shang. Reviewed by David Steele.)
* Remove stanza archive spool path on restore. (Reviewed by Cynthia Shang, Stefan Fercot.)
* Do not write files atomically or sync paths during backup copy. (Reviewed by Stephen Frost, Stefan Fercot, Cynthia Shang.)
Documentation Improvements:
* Update contributing documentation. (Contributed by Cynthia Shang. Reviewed by David Steele, Stefan Fercot.)
* Consolidate RHEL/CentOS user guide into a single document. (Reviewed by Cynthia Shang.)
* Clarify that repo-s3-role is not an ARN. (Contributed by Isaac Yuen. Reviewed by David Steele.)
The default is to keep all backup history to match the current behavior. In minimal configuration (0 days), unexpired backups are always kept in history.
When a full backup manifest expires, all dependent differential/incremental manifests expire as well.
This allows protocolRemoteExec() to be shimmed, which means the remote can be run as a child of the test process, simplifying coverage testing.
The shim does not need SSH parameters, so also split those out into a separate function and update the tests to match.
Add executable to parameter list to avoid first option being lost. The backup, restore, and verify tests worked OK with their first option being defaulted because it ended up being job-retry which worked fine as the default.
Add hrnProtocolLocalShimUninstall() allow the shim to be uninstalled.
Log shim at debug level to make it obvious in the logs when a shim is in use.
There are no code changes from PostgreSQL 13 so simply add the new version.
Add CATALOG_VERSION_NO_MAX to allow the catalog version to "float" during the PostgreSQL beta/rc period so new pgBackRest versions are not required when the catalog version changes.
Update the integration tests to handle new PostgreSQL startup messages.
manifestLinkCheck() was pretty inefficient so large numbers of links caused it to use a lot of memory and eventually crash. This is a more efficient implementation which runs O(nlogn) and uses far less memory.
Checking for duplicate file links has been added, which represents a change in behavior, but hopefully a good one.
The user guide was split primarily to provide documentation for the stop-auto option in PostgreSQL <= 9.5. Now that 9.5 is EOL there does not seem to be a good reason to generate an extra user guide. The stop-auto function is still documented in the reference.
Leave the stop-auto documentation in the user guide in case we want to manually generate documentation for older versions.
Also rename centos to rhel for most identifiers since that is the core platform we are building for, similar to how we label 'debian' builds even though we generally use Ubuntu. With CentOS set to become an upstream for RHEL later this year, we'll likely need to pick a new test distribution, perhaps Rocky Linux if that gets off the ground.
Run the local process inside a forked child process instead of exec'ing it. This allows coverage to accumulate in the local process rather than needing to test the local protocol functions directly, resulting in better end-to-end testing and less test duplication. Another advantage is that the pgbackrest binary does not need to be built for the test.
The backup, restore, and verify command tests have been updated to use the new shim for coverage.
getopt_long() requires an exhaustive list of all possible options that may be found on the command line. Because of the way options are indexed (e.g. repo1-4, pg1-8) optionList[] has 827 entries and we have kept it small by curtailing the maximum indexes very severely. Another issue is that getopt_long() scans the array sequentially so parsing gets slower as the index maximums increase.
Replace getopt_long() with a custom implementation that behaves the same but allows options to be parsed with a function instead of using optionList[]. This commit leaves the list in place in order to focus on the getopt_long() replacement, but cfgParseOption() could be replaced with a more efficient implementation that removes the need for optionList[].
This implementation also fixes an issue where invalid options were misreported in the error message if they only had one dash, e.g. -config. This seems to have been some kind of problem in getopt_long(), but no investigation was done since the new implementation fixes it.
Tests were added at 0825428, 2b8d2da, 34dd663, and 384f247 to check that previously untested getopt_long() behavior doesn't change.
Remove stanza archive spool path so existing files do not interfere with the new cluster. For instance, old archive-push acknowledgements could cause a new cluster to skip archiving. This should not happen if a new timeline is selected but better to be safe. Missing stanza spool paths are ignored.
Also add new path expression STORAGE_SPOOL_ARCHIVE to easily access this path.
When running on a GCE instance the authentication token can be pulled directly from the instance metadata. This is configured with repo-gcs-key-type=auto.
In a separate commit (26fefa6), move the code that parses the token response into a separate function, storageGcsAuthToken(), since it is now needed by two key types. This drastically improves the readability of the main commit.
927d9adb changed the way CATALOG_VERSION_NO is used to identify PostgreSQL versions since PG_CONTROL_VERSION is generally bumped with each release. The goal was to make the beta/rc period less painful because any CATALOG_VERSION_NO bump renders pgBackRest inoperative.
This worked, but in fact we'd rather be stricter about which CATALOG_VERSION_NO we accept when identifying a version of PostgreSQL. It is not just about identifying a major version, but making sure the build contains all the functions and catalogs we expect to make pgBackRest work correctly. It is better to reject early dev/beta/rc builds that may not work.
Since 927d9adb was relatively recent the chance that this stricter checking will cause a problem seems minimal, so revert to checking CATALOG_VERSION_NO for every PostgreSQL version.
Leave in place the code that pulls CATALOG_VERSION_NO from pg_control rather than the internal constant since the plan is still to allow catalog versions to "float" during the PostgreSQL beta/rc phase, which will be the subject of a future commit.
If an ok file (which indicates the WAL segment was not found) is present on the first iteration of the loop then remove it and spawn the async process to retry. This action also resets the queue.
Also error if no response is received from the async process rather than returning not found. PostgreSQL will respond the same either way, but this allows us to determine when something is going wrong with the async process.
Update archiveAsyncStatus() to allow warnings to be suppressed. It is better to retry if no WAL segment was found before warning because the warning might be stale.
Convert most of the remaining options that benefit from being StringIds. Since all the command modules can include config.h directly it makes sense to auto-generate these values instead of manually creating an enum for each one.
For the time being StringIds are not being auto-generated because the StringId code does not exist in Perl. However, the *_Z zero-terminated constants for each allowed option value are now auto-generated.
Allows removal of backupType()/backupTypeStr() and improves debug logging of the enum.
Move BackupType enum and string constants to info/infoBackup.h so they are available to more modules. Also convert InfoBackup to use BackupType instead of a String.
Using StringId for the client/session type removes String constants and some awkward referencing/dereferencing needed to use a String constant in the interface.
Converting IoSessionRole to StringId removes a conditional in ioSessionToLog() and improves debug logging by outputting client/server instead of 0/1.
Centralize the formatting of the configuration value for display to the user or passing on a command line.
For the new functions, if the value was set by the user via the command line, config, etc., then that exact value will be displayed. This makes it easier for the user to recognize the value and saves having to format it into something reasonable, especially for time and size option types.
Note that cfgOptTypeHash and cfgOptTypeList option types are not supported by these functions, but they are generally not displayed to the user as a whole.
This also fixes a bug in config/load.c where time values where not being formatted correctly in an error message.
Use StringIds for the storage types (e.g. STORAGE_S3_TYPE) and configuration settings, e.g. cfgOptS3KeyType.
Also add new config functions and harness config functions to support StringIds.
There is no need to write the file atomically (e.g. via a temp file on Posix) because checksums are tested on resume after a failed backup. The path does not need be synced for each file because all paths are synced at the end of the backup.
This functionality was not lost during the migration -- it never existed in the Perl code, though these settings are used in restore. See 59f1353 where backupFile() was migrated to C.
Fix the segfault when getting help for an internal option is requested by adding help for all internal options that are valid for a default command role.
Also print warnings about internal options in code rather than putting in each command/option description.
The remotes are no longer needed in the main process after the manifest is loaded. If the restore is long enough the connection will timeout and WARN at the end of the restore. This is harmless for the restore but distracting for the user.
To prevent this, free the remotes once they are no longer needed.
Getting help for a valid option that was invalid for the command would segfault.
Add a check to ensure the option is valid for the command's default role.
It is often useful to represent identifiers as strings when they cannot easily be represented as an enum/integer, e.g. because they are distributed among a number of unrelated modules or need to be passed to remote processes. Strings are also more helpful in debugging since they can be recognized without cross-referencing the source. However, strings are awkward to work with in C since they cannot be directly used in switch statements leading to less efficient if-else structures.
A StringId encodes a short string into an integer so it can be used in switch statements but may also be readily converted back into a string for debugging purposes. StringIds may also be suitable for matching user input providing the strings are short enough.
This patch includes a sample of StringId usage by converting protocol commands to StringIds. There are many other possible use cases. To list a few:
* All "types" in storage, filters. IO , etc. These types are primarily for identification and debugging so they fit well with this model.
* MemContext names would work well as StringIds since these are entirely for debugging.
* Option values could be represented as StringIds which would mean we could remove the functions that convert strings to enums, e.g. CipherType.
* There are a number of places where enums need to be converted back to strings for logging/debugging purposes. An example is protocolParallelJobToConstZ. If ProtocolParallelJobState were defined as:
typedef enum
{
protocolParallelJobStatePending = STRID5("pend", ...),
protocolParallelJobStateRunning = STRID5("run", ...),
protocolParallelJobStateDone = STRID5("done", ...),
} ProtocolParallelJobState;
then protocolParallelJobToConstZ() could be replaced with strIdToZ(). This also applies to many enums that we don't covert to strings for logging, such as CipherMode.
As an example of usage, convert all protocol commands from strings to StringIds.
Restore excluding the specified databases. Databases excluded will be restored as sparse, zeroed files to save space but still allow PostgreSQL to perform recovery. After recovery, those databases will not be accessible but can be removed with the drop database command. The --db-exclude option can be passed multiple times to specify more than one database to exclude.
When used in combination with the --db-include option, --db-exclude will only apply to standard system databases (template0, template1, and postgres).
Bug Fixes:
* Fix option warnings breaking async archive-get/archive-push. (Reviewed by Cynthia Shang. Reported by Lev Kokotov.)
* Fix memory leak in backup during archive copy. (Reviewed by Cynthia Shang. Reported by Christian ROUX, Efremov Egor.)
* Fix stack overflow in cipher passphrase generation. (Reviewed by Cynthia Shang. Reported by bsiara.)
* Fix repo-ls / on S3 repositories. (Reviewed by Cynthia Shang. Reported by Lesovsky Alexey.)
Features:
* Multiple repository support. (Contributed by Cynthia Shang, David Steele. Reviewed by Stefan Fercot, Stephen Frost.)
* GCS support for repository storage. (Reviewed by Cynthia Shang.)
* Add archive-header-check option. (Reviewed by Stephen Frost, Cynthia Shang. Suggested by Hans-Jürgen Schönig.)
Improvements:
* Include recreated system databases during selective restore. (Contributed by Stefan Fercot. Reviewed by Cynthia Shang.)
* Exclude content-length from S3 signed headers. (Reviewed by Cynthia Shang. Suggested by Brian P Bockelman.)
* Consolidate less commonly used repository storage options. (Reviewed by Cynthia Shang.)
* Allow custom config-path default with ./configure --with-configdir. (Contributed by Michael Schout. Reviewed by David Steele.)
* Log archive copy during backup. (Reviewed by Cynthia Shang, Stefan Fercot.)
Documentation Improvements:
* Update reference to include links to user guide examples. (Contributed by Cynthia Shang. Reviewed by David Steele.)
* Update selective restore documentation with caveats. (Reviewed by Cynthia Shang, Stefan Fercot.)
* Add compress-type clarification to archive-copy documentation. (Reviewed by Cynthia Shang, Stefan Fercot.)
* Add compress-level defaults per compress-type value. (Contributed by Cynthia Shang. Reviewed by David Steele.)
* Add note about required NFS settings being the same as PostgreSQL. (Contributed by Cynthia Shang. Reviewed by David Steele.)
The command-example and command-example-list elements were removed from the documentation rendering some time ago so these tags were dead code. The tags, however, contained some examples and information that were pertinent to the command, so where possible, the information was included in the description of the command and/or the user-guide and links to the relevant user guide sections were added.
Note that some commands could not be updated with user guide references since doing so would cause a cyclical reference in the user guide. These commands have an internal comment to indicate this.
In addition, some clarifications were added (e.g. expire --set option) where information was lacking.
