IBMSNAP_CAPPARMS table

Specifies an interval in seconds for how often the Capture log reader thread commits. The default is every 30 seconds. If you detect that Capture is creating contention with other DDL operations on the source database, you can shorten this value so that Capture commits, and releases any locks, more frequently.

The number of milliseconds that the Capture program waits for the Db2 for z/OS instrumentation facility interface (IFI) or Db2 for Linux, UNIX, and Windows log read API to return log records before Capture prints a warning to the standard output. Default: 0.

The number of seconds that the Capture program waits to issue a warning message or take other action after it detects a long-running transaction with no commit or rollback log record. On z/OS, Capture issues warning messages if has not seen a commit or rollback record for one hour (3600 seconds). On both z/OS and Linux, UNIX, and Windows, if a transaction has been running for the number of seconds that are specified in the STALE column and Capture did not see any row operations in the log for the transaction, it issues warning messages and increments the log sequence number that it considers to be the oldest "in-flight" transaction that was not committed or rolled back. If any rows were captured for the transaction, Capture only issues warning messages. Default: 3600.

Specifies whether the Capture program issues warning messages when it encounters transactions that are larger than a specified size. You provide a threshold value in megabytes, and transactions that exceed the threshold prompt a warning message. Capture issues multiple warning messages if the transaction size is a multiple of the WARNTXSZ value. For example, if you set WARNTXSZ to 10 MB and Capture encounters a 30 MB transaction, three warnings are issued (one for 10 MB, one for 20 MB, and one for 30 MB).

The default value of 0 MB means warnings are not issued.

 A flag that tells the Capture program whether to read the IBMQREP_CAPCMD table for any commands to be processed.

N (default)

The Capture program does not read from the IBMQREP_CAPCMD table.

Y

The Capture program reads the IBMQREP_CAPCMD table every n milliseconds. The frequency is determined by the value in the CAPCMD_INTERVAL column.

How frequently the Capture program reads the IBMQREP_CAPCMD table. The default is 3000 milliseconds and the minimum value is 1000 milliseconds.

This option enables you to stop the Capture program from writing data to the IBMSNAP_UOW table. It can help you avoid large buildups of UOW data and reduce Capture overhead and unneeded insert processing and pruning, but should only be used when the UOW data is not needed by the Apply program.

Y (default)

Capture always writes to the IBMSNAP_UOW table when the replication configuration calls for UOW inserts (traditional behavior).

N

Capture does not write to the IBMSNAP_UOW table if the UOW data is not needed by SQL Apply. Capture checks the IBMSNAP_PRUNCNTL table and only allows this option if the TARGET_STRUCTURE column has a value of 8 (user copy ) or 9 (CCD table without a join of the IBMSNAP_UOW and CD tables). If there are any other types of TARGET_STRUCTURE, Capture stops with an error and you must restart Capture with INSERT_UOW=Y.

Capture alone cannot determine if the UOW table is needed or not. You must use INSERT_UOW=Y if you specified UOW_CD_PREDICATES or JOIN_UOW_CD in ASN.IBMSNAP_SUBS_MEMBR table. Also, MAX_SYNCH_MINUTES must be null for all subscription sets in the ASN.IBMSNAP_SUBS_SET table.

A flag that specifies whether the Capture program checks to determine if a REORG of the source table is required before the table can be replicated.

Y (default for Db2 11 for z/OS)

Capture checks to determine if a REORG is required, and if it is required the registration is not started.

N (default for Db2 12 for z/OS)

Capture starts the registration without checking whether a REORG is required.

Starting with Db2 12, the log read API (IFI 306) returns the before and after values of a row update log record, both encoded in the version of the table at the time the log record is written. In Db2 11, the before value is encoded in the table version at the time of the insert until further updates or a REORG can be done. By returning the before value in the same format as the after value, Db2 12 removes the requirement for REORG of the table space before a registration is started for a table that was altered. This is true for a majority of cases but not all.

If Capture is behind in reading the Db2 logs and stopped, and if updates to the table are followed by a REORG of the table space, the registration fails with a decode error because Db2 cannot provide the before values in the current version and Capture did not record information about the old version because the registration was not active when the table was altered.

A flag that specifies the action that the Capture program takes when a table is dropped that is part of a registration. When a source table is dropped and recreated it can cause a mismatch between the values in the Db2 SYSIBM.SYSTABLES system catalog table and the IBMQREP_TABVERSION control table. This situation can lead to replication problems when other DDL changes are made to the source table. Specifying that the registration be deactivated (S) enables you to correct any problems before restarting replication.

W

(default) Takes no action.

S Stop

(deactivate) Stops the registration or subscription.

z/OS only: IFI_CONVERT_LOG_DATA uses the IFI306 interface with the option to return both the before and after values of log records for UPDATE operations. Log record values are returned in the format of the table that exists when the UPDATE operation is run.

z/OS only: Invokes the IFI306 log read interface with the IFI filtering by table space and partition range. The default setting is Y for V13, and N for V12.

z/OS only:When set Q Capture and SQL Capture uses Db2 for z/OS IFI306 filter for reading log records. In this log read mode, only the DMS log records for tables that are subscribed by the capture program are returned by Db2. This gives a significant performance boost, particularly if the replicated tablespaces are compressed, because the non-subscribed log records do not have to be decompressed. Reference for IFI_FILTER: IBM Support for IFI_FILTER and Qualification fields for READS requests

TRANS_COMMIT_MODE=[1,2].

1 = Commit as soon as Capture sees phase 1 to 2 or begin of phase2, either of which mean that Db2 will not back out the transaction. This value was the default before APAR PH55478.

2 = Wait until Capture sees end phase 2, or end redo if Db2 crashes during phase 2 processing.

The default is 2 with APAR PH55478 and higher.