Any backup & restore operation may be leaving opened files
if a file logger is being used. This implementes the close()
method, so every logger can close any resource.
Also, the recommended backup_controlled::destroy() method
now calls to new logger::destroy() method in charge of
deleting all the references and closing any resource.
Finally, some internally used controllers, were missing
their destroy call, leading to associated loggers to
remain open. Now all them are explicitly deltroyed.
This commit contains three changes in the three files:
1. A bug in the backup process meant that anything logged after a
certain point did not appear in the on-screen display of the
backup log, because the logger was serialised and deserialised
but display code referred to the old version. Changed so that
code retrieves new object.
2. Add more information to backup log when there is a missing file.
3. Add more information to restore log when there is a missing file
(and remove existing code duplication of the current message).
The 'missing file' situation is one that generally shouldn't occur in
normal usage, but when it does happen, it is useful to have full
information about the file.
When restoring a backup that contains a large number of users
to a different server where those users don't already exist,
creating users can take a significant time. This change adds
progress reporting so that it doesn't time out and shows
activity in the user interface while doing the creation.
1. Changes progress bar code to allow headings for progress bar (so users have
some clue what's going on if a page has more than one progress bar).
2. Changes restore code so that a progress bar can display during pre-checks if
they take longer than 5 seconds.
3. Changes pre-check and restore code so that, in various points where the system
can take a long time within an individual step, intederminate progress is
indicated and it won't time out.
encode_backup_temp_info() and decode_backup_temp_info() have been
introduced to keep the info field encoding in one place.
Many locations used get_backup_ids_record() to obtain info, that
makes lots of calls to get_backup_ids_record() which can be slow.
We now complete all those inline by adding the info field to the query.
To reduce memory usage, all queries of that nature have been changed
to use get_recordset_*. gzcompress was introduced if available to minimize
traffic to/from the database and to decrease the memory required for caching.
The compression time is saved by the benefits in other places of having smaller data.
The cache is function local and testing against a large database
indicates 10k questions is a large category. Restore already
uses MEMORY_EXTRA and that will have enough space for the couple
of megabtyes a local sql hash will introduce.
When we import courses or duplicate activities, the deduplicating nature of
the file_storage system means that we don't actually have to include the
real files in the backup - just their metadata from the file table.
The restoration process needs to know not to expect files from the backup
phase so a flag is set in moodle_backup metadata.
Some early steps in restore are using capability checks to decide how to
restore some information. But at that stage, if the course contents have
been removed and the user had perms at course level only (usually teacher)
the process can fail because some content is not restoreable due to the
lack of permissions.
Moving the restorer step to the beginning really helps is those situations
and it does not hurt at all.
Also, fixed one notice detected when testing this.
