Chained Row Analysis (ORCL)

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Updates can cause data rows to migrate and to chain over multiple data blocks. Chaining degrades performance because more physical reads are required to access a row of data. Consequently, you should monitor chained rows regularly to spot performance bottlenecks before they become severe.

To avoid chained rows, you can tune the Percent Free storage settings for that table or cluster. By increasing the Percent Free on each data block, you decrease the likelihood that an update causes a data row to expand over multiple data blocks.

If the row length is greater than the size of a data block, you cannot avoid chained rows.

DBArtisan provides a utility that lets you identify chained rows quickly by displaying chained rows for all or any schema in your Oracle database.

Analyzing Chained Rows

  1. On the Utilities menu, select Chained Row Analysis.
    DBArtisan opens the Chained Row Analysis dialog.

The table below describes the options and functionality on the Chained Row Analysis dialog:

Option Description


Lets you select the owner for whom you want to scan for chained rows.

Refresh Button

Click to refresh the list.