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  1. Moodle
  2. MDL-35129

Database Transfer Tool Transfers Tables/Schemas But No Data (MySQL -> Postgres)

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 2.3.1, 2.4
    • Fix Version/s: 2.3.3
    • Component/s: Database SQL/XMLDB
    • Labels:
      None
    • Testing Instructions:
      Hide

      1/ get some very large MySQL site which has table that can not fit available memory
      2/ try Development / Experimental/ Database migration with any database as target (by anything I mean something that works properly - not MSSQL or Oracle)

      It should not run out of memory any more.

      Show
      1/ get some very large MySQL site which has table that can not fit available memory 2/ try Development / Experimental/ Database migration with any database as target (by anything I mean something that works properly - not MSSQL or Oracle) It should not run out of memory any more.
    • Affected Branches:
      MOODLE_23_STABLE, MOODLE_24_STABLE
    • Fixed Branches:
      MOODLE_23_STABLE
    • Pull from Repository:
    • Pull Master Branch:
      w38_MDL-35129_m24_dbmigration

      Description

      In attempting to use the database transfer tool to migrate my MySQL database to Postgres (the replication step here, which I've done several times, is simply "create a new Postgres database according to the instructions at http://docs.moodle.org/23/en/PostgreSQL, then use the database transfer tool with correct parameters), I have observed the following behavior:

      • the transfer tool reports its progress throughout the process, and seems to take significant time and significant CPU cycles/memory for postgres, mysqld, and php (this is a transfer to a new database on the same host), so it looks like it's doing its job
      • the transfer tool reports no error messages, even with maximal error reporting turned on
      • the resulting Postgres database contains all the required tables, but no data

      My original MySQL database is fairly large (29GB, with a 2.8GB gzipped mysqldump), and the various software components (in particular /usr/bin/php) seem to want to use a lot of memory - I have php limited to 1 GB for regular usage, and it pegs that limit during this process. Is it possible that a memory limitation is causing this not to work? In any event, the fact that it does not work and also does not give an error message of any kind is a problem...

      The software versions involved are Moodle 2.3.1+ (20120823), MySQL 5.5.27, and PostgreSQL 9.1.5.

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                Dates

                • Created:
                  Updated:
                  Resolved:
                  Fix Release Date:
                  12/Nov/12