What is run stats DB2?

What is run stats DB2?

RUNSTATS is a DB2 utility that scans a table space or indexes to gather information about space utilization and index efficiency. The information gathered is stored in the DB2 system tables and used by the SQL optimizer to select the best access paths during the bind process.

When should I run my Runstats?

When to Run Runstats in DB2

1. When a table is loaded.
2. When an index is created.
3. When a tablespace is reorganized.
4. When there have been extensive updates, deletions, or insertions in a tablespace.
5. After the recovery of a tablespace to a prior point in time.

How do you run a Reorgchk?

Procedure

1. Log in with the directory server instance owner credentials.
2. Connect to the database. db2 connect to ldapdb2.
3. Run the reorgchk command. db2 reorgchk update statistics on table all.
4. To generate an output file with the database statistics, run the reorgchk command and redirect the output to a file.

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.

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 reorg 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 is Reorg and Runstats in Db2?

What is load utility in Db2?

The LOAD utility loads records into the tables and builds or extends any indexes that are defined on them. You can use the LOAD utility in conjunction with z/OS® DFSMS data set encryption with the REPLACE option to encrypt or decrypt table spaces or indexes that use Db2-managed data sets.

What is Reorg and Runstats in DB2?

Why do we need reorg in DB2?

What is the difference between reorg and Runstats in DB2?

RUNSTATS does nothing to the data itself. REORG on the other side moves and organizes data (table or index data). Rows marked as deleted will be deleted, data may be reorganized to a certain index to get it ordered and more efficient to fetch in certain situations.

How do I know if my table needs reorg?

The column at the far right is what tells us that a table reorg is actually needed.

What is runstats in DB2?

Runstats is a utility in Db2 that is used to collect statistics about the data in Db2 tables and indexes. This statistical information is critical to Db2 database performance.

How many quantiles are used for distribution statistics 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.

What is the sampled parameter in DB2?

The SAMPLED parameter is left in for compatibility with previous versions of Db2®. This parameter cannot be used for views. This option, when used with the DETAILED option, forces RUNSTATS to examine every entry in the index to compute the extended index statistics.

Can I collect distribution statistics over XML type columns in DB2?

For DB2® V9.7 Fix Pack 1 and later releases, distribution statistics over XML type columns are not collected when this clause is specified. Instead of listing specific columns, you can choose to collect statistics on columns that make up all the indexes defined on the table.