Methods for Minimizing Log Table Size - Teradata Database

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Methods for Minimizing Log Table Size

There are several ways you can minimize the size of your DBQL log tables and therefore avoid running out of disk space in DBC:

  • Regularly clean up DBQL log tables by offloading them to history tables. This is especially necessary if you are also doing detail logging. (That is, logging steps, objects, SQL, or Explain). You should do this daily if not several times a day.
  • You can also create temporary tables to move data from the DBQL logs before doing an INSERT ... SELECT in to your history tables to minimize contention.

  • Use PPIs on your DBQL history tables. If you prefer not to use a PPI, use a SI on the date column for your history table.
  • Add a date column to avoid multiple casting of the time columns.
  • Use MVC on the columns of the copies of DBQL tables.
  • Do not use fallback on your historical copies of DBQL tables. Using both NO FALLBACK and compression will save a lot of disk space.
  • Log only the data you need. For example, if default data in DBQLogTbl is sufficient, do not log WITH SQL or WITH OBJECTS as well.
  • Limit summary logging to just the accounts you want to track.
  • Limit SQL text logging to a specific number of characters.
  • Remember to end logging whenever logging data is no longer needed for a specific user, group of users, account, list of accounts, or applications.