2015-09-18

Access path stability features were first introduced in DB2 9 for z/OS in the maintenance stream. More complete support came \൩n DB2 10. – BIND / REBIND with EXPLAIN(ONLY) added. DB2 10 added catalog support for the inactive “copies” of a package.

For a list of all EXPLAIN tables, see EXPLAIN tables. A plan table must exist before the operation that results in EXPLAIN output. You can find a sample CREATE TABLE statement for each EXPLAIN table in member DSNTESC of the prefix. For joins of tables, EXPLAIN indicates the join method and type, the order in which Db2 joins the tables, and the occasions when and reasons why it sorts any rows. The following steps summarize how to obtain information from EXPLAIN: Create the plan table. Before you can use EXPLAIN, you must create a plan table to hold the results of EXPLAIN. The EXPLAIN functionality of Db2 for z/OS, by which the query optimizer's access path determinations are externalized, has been around as long as I can remember, and Db2 people, by and large, are familiar with the concept.

DB2 10 introduces a new privilege called EXPLAIN. By granting the EXPLAIN privilege on an authid or role, you are giving that authid or role the ability to . do an EXPLAIN on an SQL statement specifying the keywords DB2 Commands and Features: Apart from the obvious DB2 group restart or IPL any type of RUNSTATS is poison to the DSC! • RUNSTATS TABLESPACE will delete any statements that use any object within the TABLESPACE regardless of any TABLE (xxx.yyy) syntax. • RUNSTATS INDEX will delete statements that use that index. Formatting DB2 z/OS SQL I have Data Studio 4.1.3 installed but can't currently get Visual Explain to open (separate problem), so even if DS indents text, Developers and Database Administrators using Db2 for z/OS Description Get ready to tackle a variety of Db2 topics that will take any developer or DBA to the next level. Being new on z/OS for some time I do have some problems with Explain.

If the PREPARE of the EXPLAIN statement is run locally, DB2 determines if the rowset query can be accelerated as a local query offload. However, if the PREPARE of the EXPLAIN statement runs remotely, DB2 indicates that the rowset query cannot be accelerated. Instead, you can use the CURRENT EXPLAIN MODE special register to determine the behavior for eligible dynamic SQL statements during application execution.

Show More Show Less. Db2 for z/OS CHAR versus VARCHAR, Part 2 - a DBA's Story. Last month, I posted to this blog an entry in which I provided my thoughts on the CHAR (fixed-length) versus the VARCHAR (varying-length) data type for character string columns in Db2 for z/OS tables.

DB2 11 for z/OS: The SYSPROC.ADMIN_EXPLAIN_MAINT stored procedure maintains EXPLAIN tables under a specified schema. It can be used to: bring all existing EXPLAIN tables to current release format;

use stored procedures and triggers.

CA Plan Analyzer for DB2 for z/OS CA Database Management for DB2 for z/OS - Performance Suite CA RC/Query for DB2 for z/OS. CT Create Explain/Input Tables. Db2 12 for z/OS •Upgrade EXPLAIN tables to Db2 12 for z/OS format (should be at least Db211for z/OS version) –Can be done in Db211for z/OS NFM with fallback SPE applied –Use of sample batch job DSNTIJXA with REXX DSNTXTA can help •Apply PTFs for APARs PI69589 (Db2 11 for z/OS) & PI69584 (Db2 12 for z/OS) Db2 for z/OS: Application Programming - Advanced Topics This course is designed for the experienced Db2 developer, focusing on advanced SQL statements and options. Additionally, the Db2 EXPLAIN facility is discussed as a tool to be used when choosing amongst competing SQL and design alternatives. The course describes and explains in detail the components, utilities and procedures involved in data and system backup and recovery, together with the various methods of utilising them to ensure maximum availability. This course is applicable to all Db2 for z/OS environments, up to and including Db2 11 for z/OS. Much of the class will be in workshops where the participants will code and review queries, execute Db2 Explains, and perform analysis on the information.
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An Introduction to SQL Tuning for aDB2 for z/OS EnvironmentWillie FaveroData Warehouse on System z Swat Team (DB2 SME)Session #8762Tuesday, March 1, 2011: 3:00… If you are using Data Studio, it can create the explain tables for you.

DB2 10 introduces a new privilege called EXPLAIN. By granting the EXPLAIN privilege on an authid or role, you are giving that authid or role the ability to .
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This release of DB2 for z/OS includes new and changed commands. changes that affect performance and changes to monitoring tools, such as EXPLAIN.

Before you can use EXPLAIN, you must create a plan table to hold the results of EXPLAIN. Output from EXPLAIN: DB2 inserts one or more rows of data into a plan table and other existing EXPLAIN tables. For a list of all EXPLAIN tables, see EXPLAIN tables. A plan table must exist before the operation that results in EXPLAIN output.

Abel svedin
csn frånvaro universitet

2010-07-12

These cookies are necessary for the website to function and cannot be switched off in our systems. They are usually only set in response to actions made by you which amount to a request for services, such as setting your privacy preferences, logging in or filling in forms. 2010-07-12 · DB2 gets index key cardinality information from the catalog, so it pays to ensure that catalog statistics are accurate through regular execution of the RUNSTATS utility; but, there's more: to provide DB2 with really complete information on index key cardinality, specify the KEYCARD option on the RUNSTATS utility control statement. The new EXPLAIN privilege provided by DB2 10 for z/OS is tailor-made for the situation you're facing. A user (a programmer, for example) with this privilege can successfully EXPLAIN SQL statements without having the privileges needed to actually execute the statements. To generate the explain graph - simply highlight your query, right click, and choose "Open Visual Explain": To use the query advisor , choose "start tuning" instead. It will take you through a process which will generate the explain, as well as recommend any tuning opportunities it can determine.