holland-coredev team mailing list archive

[Andrew Garner <677718@xxxxxxxxxxxxxxxxxx>]

Basically what holland-mysqldump does is, given a set of
inclusion/exclusion filters generate a mysqldump command line to backup
the requested tables.   However, mysqldump itself has *very* primitive
support for inclusion/exclusions.  This support basically falls into
three categories:

1) Dump specific tables from *one* database only  => mysqldump [options]
database table [table..]

2) Dump multiple databases and exclude specific tables => mysqldump
[options] --ignore-table=db.tbl --databases db [db...]

3) Dump all databases and exclude specific tables => mysqldump [options]
[--ignore-table=db.tbl...] --all-databases

If we have a single 'tables' request, we may be able to hard code a fast
path for that to always choose (1).   If it includes a pattern we still
have to scan a potentially large number of tables to find matches.   If
"tables" includes tables from multiple databases but file-per-
database=off (meaning, the user wants a consistent snapshot of all those
tables via a single mysqldump command) there's not a good way to support
that without generating a large list of --ignore-table options.

I think the common use case is to simply filter a few tables and
otherwise back everything else up.   You can always manipulate the
mysqldump command line through holland via additional-options.   For
efficient inclusion/exclusion we would need support from mysqldump (or a
similar backend).  I'm skeptical that the additional complexity in
holland-mysqldump to more efficiently handle edge cases here is
warranted currently.   Although perhaps I'm just not aware of
interesting use cases.

Essentially I view this as a limitation in mysqldump itself and holland
has a reasonable general purpose filtering algorithm.  I'm completely
open to contributions to provide better alternatives - either as new
plugins or reworking the existing "Given a set of filters, run these
mysqldump commands" algorithm.


** Changed in: holland-backup
   Importance: Undecided => Low

-- 
provider crawls all tables and excludes rather than just including specified tables
https://bugs.launchpad.net/bugs/677718
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Status in Holland Backup Framework: New

Bug description:
If you have:

[mysqldump]
tables             = "foo.importantTable'

You will see holland do something along the lines of:

Excluding mysql.columns_priv
Excluding mysql.db
Excluding mysql.func
Writing ignore-table exlusions to  /var/spool/holland/bkset/20101120_022118/my.cnf

This could be really inefficient on a server with thousands of tables when you want just the one