Parameters and variables

As much as is possible, Replication Agent is pre-configured for best performance when an instance is created with the following default configuration property values:

**Table 3-1: Parameters and defaults at instance creation**
Parameter	Default
column_compression	true
compress_ltl_syntax	true
lti_batch_mode	true
lti_update_trunc_point	10000
ltl_batch_size	40000
ltl_origin_time_required	false
ltl_send_only_primary_keys	true
rs_packet_size	2048
structured_tokens	true
use_rssd	true

The following configuration properties can affect performance throughput and may need tuning, but they must be tuned based on environmental factors, such as hardware resources, primary database schema, and transaction profile:

**Table 3-2: Parameters affecting performance throughput**
Parameter	Default
archive_read_block_count	64
auto_adjust_block_count	true
log_read_block_count	64
lr_max_op_queue_size	1000
lr_max_scan_queue_size	1000
lr_parallel_scan	false
lti_max_buffer_size	5000
rasd_object_cache_size	1000

The archive_read_block_count parameter is used only for Oracle databases. The lr_parallel_scan parameter is used only with Oracle RAC databases.

Depending on the replication environment and system resources as well as the database schema and transaction profile, the maximum memory configuration can also affect performance throughput. The Replication Agent maximum memory configuration is determined by the RA_JAVA_MAX_MEM environment variable if this variable has been set. See “Default heap size”.

The following configuration parameters affect performance latency. However, the defaults for these parameters are prioritized for performance throughput, and adjustments made to these parameters to decrease performance latency may negatively affect performance throughput.

**Table 3-3: Parameters affecting performance latency**
Parameter	Default
dump_batch_timeout	5
scan_sleep_increment	5
scan_sleep_max	60

For information about these configuration parameters, see the Replication Agent Reference Manual.