What is Reorg and Runstats?
runstats is for collecting indexes and tables statistics information which to enable the DB2 optimizer to generate efficient access plan. reorgs is for reorganizing tables and indexes.
What is the use of reorg in DB2?
The REORG TABLE command reorganizes a table by reconstructing the rows to eliminate fragmented data, and by compacting information. On a partitioned table, you can reorganize a single partition.
Can we kill Runstats in DB2?
Unfortunately we will not be able to stop a runstats while it is running.
What is output of Runstats utility?
The output from RUNSTATS consists of DB2 updates to any or all of the following tables, depending on whether RUNSTATS was executed for a table space, indexes, or both: SYSIBM. SYSCOLUMNS.
How do I check my Runstats?
Monitoring the progress of RUNSTATS operations You can use the LIST UTILITIES command or the db2pd command to monitor the progress of RUNSTATS operations on a database.
How do you run a Reorgchk?
Procedure
- Log in with the directory server instance owner credentials.
- Connect to the database. db2 connect to ldapdb2.
- Run the reorgchk command. db2 reorgchk update statistics on table all.
- To generate an output file with the database statistics, run the reorgchk command and redirect the output to a file.
Why reorg is required?
Reorganizing a table reclaims empty pages and reduces the amount of space that a table uses. In addition, because empty pages are read into the buffer pool during a table scan, reclaiming unused pages can improve scan performance.
What is Rbind in DB2?
This command uses the rebind API (sqlarbnd) to attempt the re-validation of all packages in a database. Use of db2rbind is not mandatory. For packages that are invalid, you can choose to allow package revalidation to occur implicitly when the package is first used.
When should I run my Runstats?
When to Run Runstats in DB2
- When a table is loaded.
- When an index is created.
- When a tablespace is reorganized.
- When there have been extensive updates, deletions, or insertions in a tablespace.
- After the recovery of a tablespace to a prior point in time.
How does reorg work in DB2?
To keep it simple: REORG is a database operation that is executed in DB2 to reorganize the table spaces or index spaces. The purpose of the reorganization is data clustering. This operation reconstructs the data in the table spaces or index spaces, so that the data is unfragmented and physically continuous.
What’s the difference between runstats and reorgs in DB2?
Viewed times. DB2 provide multiple tools and utilities for the maintenance, with these tools and utilities, it’s more convenient for DBA to manage the DB2 database. runstats is for collecting indexes and tables statistics information which to enable the DB2 optimizer to generate efficient access plan. reorgs is for reorganizing tables and indexes.
When to use the runstats command in SQL?
For a statistical view, call the RUNSTATS command when changes to underlying tables substantially affected the rows that are returned by the view. The view must be previously enabled for use in query optimization by using the ALTER VIEW statement. You can issue the RUNSTATS command from any database partition in the db2nodes.cfg file.
What’s the default number of quantiles in DB2?
For Db2 V9.7 Fix Pack 1 and later releases, distribution statistics for each index over XML data uses a maximum of 250 quantiles as the default. The default can be changed by specifying the NUM_QUANTILES parameter in the ON COLUMNS or the DEFAULT clause.
