Overview of multithreaded database apply processing - assure_mimix - 10.0

Assure MIMIX Administrator Reference

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Assure MIMIX™ Software
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Assure MIMIX
Assure MIMIX Administrator Reference
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The use of application groups and resource groups is a required for multithreaded database apply processing. The actual database apply jobs run at the data group level.

When a data group has multithreading configured, database apply session A is used solely for journaled IFS, data area, and data queue objects. Apply session A is present even if you do not have these objects configured for user journal replication.

Apply session B is used solely for journaled physical and logical files and has an associated multithreaded job that starts and ends with apply session B. The actual number of threads allowed is determined by the license for your product. Apply session B performs pre-apply operations for all transactions to be applied, applies more complex transactions for member and file operations, and delegates blocks of record-level transactions to be applied by the multithreaded job. After the threaded job completes a block of transactions, apply session B updates status, counts, and the last applied sequence number. Apply session B performs error handling for any transactions that could not be processed by the threaded job, and either retries the operation or submits a recovery request. The name of the multithreaded job is sdn_DBAPYT, where sdn is the short data group name.

When multithreading is configured, MIMIX ignores the DB apply cache (DBAPYCACHE) and Access path maintenance (APMNT) policies. With multithreading, triggers are disabled for all files when the apply process starts. (When single-threading is used, triggers are disabled at the time files are first opened.)

Starting and ending the multithreaded job: When multithreaded database apply processing is configured, the multithreaded job is automatically included in requests to start or end the database apply processes that specify either apply session B or all apply sessions. This affects the Start Data Group dialog, Stop Data Group dialog, Start Data Group (STRDG) command, End Data Group (ENDDG) command, as well as any other step programs or commands that invoke the STRDG or ENDDG commands.

Status reporting: The status of the multithreaded job is included in the DB Target column on the Work with Data Groups (WRKDG) display. Detailed status for the multithreaded job (DBAPYT) appears in the following views of Display Data Group Status (DSPDGSTS). Possible status values for the job are: -I (inactive, red), -V (ended due to virtual switch in progress, yellow), -A (active, blue), and -U (unknown, white).

  • Merged view: The process DBAPYT appears in the statuses listed horizontally in the Target Statistics section.

  • DB views 1 and 2: The process DBAPYT appears to the left of the Held for other reasons field in the top half of the display.

  • DB view 3: The process DBAPYT appears in the Target system row, above the Database Apply section.