Db2 12 z/OS DBA flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

DIST address space

The Db2 distributed data facility address space that handles DRDA and distributed requests from remote clients, using DDF threads and enclaves to access local data.

DBM1 address space

The Db2 database services address space that manages buffer pools, thread storage, and most database processing for local SQL requests.

DSNTIJTC job

The Db2 catalog migration job used when migrating to a new release or function level; it updates the Db2 catalog and directory structures.

Function level

A Db2 12 concept that controls which new features are enabled; function levels run from V12R1M500 upward and are activated separately from catalog migration.

APPLCOMPAT

A package or plan bind option that sets the application compatibility level, controlling which SQL behaviors and features are available to that application.

IRLM

The Internal Resource Lock Manager that provides locking services for Db2, managing lock requests and coordinating with the lock structure in data sharing.

DSNZPARM

The Db2 subsystem parameter module that holds configuration settings; many can be changed online with -SET SYSPARM, others require a restart.

Table-controlled partitioning

A partitioning method where partition limits are defined in the table's PARTITION BY clause rather than in a partitioning index, simplifying partition management.

Clustering index

An index that determines the physical order of rows in a table; only one clustering index per table, and it must be a partitioning index for partitioned table spaces.

Universal table space

A modern table space type that supports segmented, partitioned, and LOB data in a single structure; the default for new table spaces in Db2 12.

System-period temporal table

A table with a history table that automatically tracks versions of rows over time, using a transaction ID and system time period.

Identity column

A column defined with GENERATED ALWAYS or BY DEFAULT that automatically generates values; values are not guaranteed to be gap-free.

Referential integrity

A constraint that ensures a child table's foreign key values match a parent table's primary key, with delete rules such as RESTRICT, CASCADE, or SET NULL.

Stage 1 predicate

A predicate that Db2 can evaluate during data access, often using an index; stage 1 predicates are more efficient than stage 2 predicates.

Merge scan join

A join method that sorts both inputs and merges them; efficient for large inputs but requires sort work files and may be costly.

Hybrid join

A join method that sorts the outer table and uses an index on the inner table for each outer row in sort order, reducing random I/O.

Covering index

An index that contains all columns referenced by a query, allowing index-only access and avoiding table space access, improving performance.

PLANMGMT

A bind option that retains previous access paths for a package or plan, allowing fallback if a rebind produces a worse plan.

Cursor stability

An isolation level that holds locks on the current row only, allowing high concurrency but permitting non-repeatable reads.

RUNSTATS

A utility that gathers table, index, and column statistics for the optimizer; supports FREQVAL, HISTOGRAM, and sampling options.

REORG utility

A utility that reorganizes table spaces and indexes to reclaim space and improve clustering; supports SHRLEVEL CHANGE for concurrent access.

Inline image copy

An image copy taken during a LOAD or REORG utility execution, reducing the need for a separate COPY job and improving availability.

CHECK DATA utility

A utility that validates referential integrity and check constraints, identifying violations that put objects in check pending status.

BSDS

The bootstrap data set that records log inventory and other critical control information; it must be backed up and is essential for recovery.

TORBA recovery

A point-in-time recovery option that restores to the last commit point before a specified time, using log records.

Dual logging

A Db2 option that writes log records to two active log data sets simultaneously, improving availability if one log is lost.

Group buffer pool

A coupling facility structure in data sharing that caches pages for cross-member access, reducing disk I/O and improving availability.

Lock structure

A coupling facility structure used in data sharing to manage global locks across members, coordinating concurrent access to shared data.

RLF

The Resource Limit Facility that controls CPU consumption for dynamic SQL, using tables to define limits and prevent runaway queries.

Trusted context

A Db2 feature that allows a middle-tier server to establish a trusted connection with a user's identity, simplifying security for distributed applications.

Row and column access control

A Db2 feature that enforces row permissions and column masks at the engine level, providing fine-grained data access control.

SCA

The shared communications area, a coupling facility structure used in data sharing for member status and communication among Db2 members.