The following settings and configurations maybe optimized in high volume transactions to achieve higher performance.
| Variable | Description |
|---|---|
| STATUS_BEAT_LCR | This determines how often a log message is written showing number of processed LCRs (in LCR count) (use 0 to disable). As of Dbvisit Replicate 2.3.14 the default is 10,000. For high volume configurations consider increasing to higher number. |
| OCI_COMMIT_MODE = NOWAIT BATCH | This may improve apply processing speed. Only set for non RAC target systems. See Configuration Variable Reference for more information. |
| _ENABLE_5_19_PARSE = NO | Disables processing of auditing information. This information is used by CDC/Audit function or by querying the DBRSAPPLY_PKG package on the target database (e.g. in triggers). This information includes source sid, serial#, transaction id, os user, os machine, login name. If this information is not required, then this can be disabled. Please Internal Variables for more information |
Improving performance
Following settings/tips can be applied to improve Replicate performance. Please test them first on a test system before implementing in a production environment.
| Process | Type | Description | Setting |
|---|---|---|---|
Mine | No CDC/AUDIT | Disable maintaining of session information. This information is needed only if CDC/Audit is in use to populate auxiliary fields such as source user login, program, module, action and so on. If _MINE_PRINT_OPEN_TRANSACTIONS is used, this feature populates the sid/serial info. | _ENABLE_5_19_PARSE = NO |
No trace files | Disable keeping of past debug messages. So the trace files will not contain this information. This is only recommended in a tested environment.
| _DISABLE_DBGPRINTF = YES | |
No redo log checksums | Disable checking of redolog checksums. This is recommended only if
| _MINE_CHECK_ORACHECKSUM = NO | |
No error logging to database | Do not log errors to DBRSCOMMON_ERRORLOG. Note that this decreases the table size and not performance. | _LOG_ERRORS_TO_DATABASE = NO | |
Less frequent updates of table names in list progress | This setting only updates table names in list progress when a log switch occurs. Note that new tables are added on the fly even with this setting. The setting can confuse if there is a lot of DDL, table renames etc. Then list progress may show stale information until next log switch happens. | _MINE_UPDATE_TABLIST_ON_SWITCH_ONLY = YES | |
| Apply | No trace files | See Mine | |
| No error logging to database | See Mine | ||
| Commit Nowait | Change default commit settings. Use only if target is not RAC, otherwise data loss can occur. | OCI_COMMIT_MODE = NOWAIT BATCH | |
| No audit info, no triggers | f DBRSAPPLY_PKG is used at all, apply can stop populating it's variables. It's used for:
| _SET_APPPLY_PKG_AUDIT NO (on login) _SET_APPPLY_PKG_CONFLICT NO (on conflict) _SET_APPPLY_PKG_ALWAYS NO (on each change; NO is the default) | |
Examples:
This shows an example of how to change the settings to further improve the performance:
Please add these settings to your MINE ddc file on the source server:
memory_set _ENABLE_5_19_PARSE NO -- this disables auxiliary data like action, module, osprog, osproc etc. available on apply with CDC/Audit or using the DBRSAPPLY_PKG package
memory_set _DISABLE_DBGPRINTF YES -- this disables most of the contents of trace files
memory_set _MINE_CHECK_ORACHECKSUM NO -- disable checking of redo log checksums
memory_set _LOG_ERRORS_TO_DATABASE NO -- disables logging of errors to DBRSCOMMON_ERRORLOG table
memory_set _MINE_UPDATE_TABLIST_ON_SWITCH_ONLY YES -- updates table names in list progress only on log switch; so if you rename a table, you won't see the change until a log switch
Please add these settings to your APPLY ddc file on the target server:
memory_set _DISABLE_DBGPRINTF YES
memory_set _LOG_ERRORS_TO_DATABASE NO