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MAX_STRING_SIZE – stretching the dictionary

This post cycles back too some other historical posts of mine related to max_string_size and the fact that the data dictionary uses LONG data type columns because of historical reasons related to backward compatibility. Most of us probably have existing databases that have gone through the standard upgrade through various versions of the Oracle Database, and as such, all of our existing database have a max_string_size of STANDARD. Thus to convert to the larger string size, we start by setting max_string_size to EXTENDED, run the appropriate scripts after shutting out database down and re-opening it in upgrade mode, setting the appropriate initialization parameters for the instance in our SPFILE. But what if you are creating a new database?

Read only partitions

The ability for part of a table to be read-only and other parts of the same table to allow full DML is a cool feature in the Oracle Partitioning option.  Perhaps the most common example you will typically see for this is range-based partitioning on a date/timestamp column.  As data “ages”, setting older partitions to read-only can yield benefits such as:

  • moving the older partitions to cheaper, or write-once storage
  • guaranteeing that older data cannot be tampered with
  • shrinking backup times because read-only data only needs to be backed up once (or twice to be sure)

But if you try this in 18c, you might get a surprise:

PeopleSoft and Invalid Views in the Oracle Database

I was listening to the section on Invalid Views in PSADMIN Podcast #117 (@19:00). Essentially, when you drop and recreate a view that is referenced by a second view, the status on the second view in the database goes invalid. This is not a huge problem because as soon as you query the second view it is compiled. However, you would like to know whether any change to a view prevents any dependent views from compiling, although you would expect have teased these errors out before migration to production.