rs_init sets default configuration parameters after you install your Replication Server. You can change the values of the configuration parameters shown in Table 4-2 to improve Replication Server performance.
See “Changing Replication Server parameters” on page 96 in the Replication Server Administration Guide Volume 1 for information on how to modify these parameters using configure replication server.
Configuration parameter |
Description |
|---|---|
block_size to ‘value’ with shutdown |
Specifies the maximum queue block size. The queue block size is the number of bytes in a contiguous block of memory used by stable queue structures. Range of values allowed: 16KB, 32KB, 64KB, 128KB, or 256KB Default: 16KB
License: Separately licensed under the Advanced Services Option. . See “Increasing queue block size” for instructions. |
db_packet_size |
The maximum size of a network packet. During database communication, the network packet value must be within the range accepted by the database. You may change this value if you have Adaptive Server that has been reconfigured. Maximum: 16,384 bytes Default: 512-byte network packet for all Adaptive Server databases |
deferred_queue_size |
The maximum size of an Open Server deferred queue. If Open Server limits are exceeded, increase the maximum size. The value must be greater than 0.
Default: 2,048 on Linux and HPIA32 1024 on other platforms |
disk_affinity |
Specifies an allocation hint for assigning the next partition. Enter the logical name of the partition to which the next segment should be allocated when the current partition is full. Values are “partition_name” and “off.” Default: off |
dist_direct_cache_read |
Enables the distributor (DIST) thread to read SQL statements from the Stable Queue Thread (SQT) cache directly. This reduces contention between the inbound and outbound queues, and leads to improved Replication Server performance. Default: on |
dsi_bulk_copy |
Turns the bulk copy-in feature on or off for a connection. If dynamic_sql and dsi_bulk_copy are both on, DSI applies bulk copy-in. Dynamic SQL is used if bulk copy-in is not used. Sybase recommends that you turn dsi_bulk_copy on to improve performance if you have large batches of inserts. Default: off. |
dsi_bulk_threshold |
The number of consecutive insert commands in a transaction that, when reached, triggers Replication Server to use bulk copy-in. When Stable Queue Transaction (SQT) encounters a large batch of insert commands, it retains in memory the number of insert commands specified to decide whether to apply bulk copy-in. Because these commands are held in memory, Sybase suggests that you do not configure this value much higher than the configuration value for dsi_large_xact_size. Replication Server uses dsi_bulk_threshold for Real-time loading (RTL) replication to Sybase IQ and High volume adaptive replication (HVAR) to Adaptive Server. If the number of commands for an insert, delete, or update operation on one table is less than the number you specify after compilation, RTL and HVAR use language instead of bulk interface. Minimum: 1 Default: 20 |
dsi_cmd_batch_size |
The maximum number of bytes that Replication Server places into a command batch. Default: 8192 bytes |
dsi_cmd_prefetch |
Allows DSI to pre-build the next batch of commands while waiting for the response from data server, and therefore improves DSI efficiency. If you also tune your data server to enhance performance, it is likely that you will gain an additional performance increase when you use this feature. Default: on When you set dsi_compile_enable to ‘on’, Replication Server ignores what you set for dsi_cmd_prefetch. License: Separately licensed under the Advanced Services Option. See “Replication Server – Advanced Services Option”. |
dsi_max_xacts_in_group |
Specifies the maximum number of transactions in a group. Larger numbers may improve data latency at the replicate database. Range of values: 1 – 1000. Default: 20 |
dsi_non_blocking_commit |
Specifies the number of minutes to extend the period of time Replication Server saves messages after a commit. Range of values: 0– 60 minutes. Default: 0 – means that non-blocking commit is disabled. Enable this parameter to improve replication performance when the delayed commit feature is available in Adaptive Server 15.0 and later or the equivalent feature is available in Oracle 10g v2. |
dsi_xact_group_size |
The maximum number of bytes, including stable queue overhead, to place into one grouped transaction. A grouped transaction is a set of transactions that the DSI applies as a single transaction. A value of –1 means no grouping. Sybase recommends that you set dsi_xact_group_size to the maximum value and use dsi_max_xacts_in_group to control the number of transactions in a group. Maximum: 2,147,483,647 Default: 65,536 bytes |
dynamic_sql |
Turns dynamic SQL feature on or off. Other dynamic SQL related configuration parameters will only take effect if this parameter is set to on. Default: off |
dynamic_sql_cache_size |
Gives the Replication Server a hint on how many database objects may use the dynamic SQL statement for a connection. Default: 100 Minimum: 1 Maximum: 65,536 |
dynamic_sql_cache_management |
Manages the dynamic SQL cache for a DSI executor thread. Values: mru - keeps the most recently used statements and deallocates the rest to allocate new dynamic statements when dynamic_sql_cache_size is reached. fixed (default) - Replication Server stops allocating the new dynamic statements once dynamic_sql_cache_size is reached. |
exec_cmds_per_timeslice |
Specifies the number of LTL commands an LTI or RepAgent executor thread can process before yielding the CPU. By increasing this value, you allow the RepAgent executor thread to control CPU resources for longer periods of time, which may improve throughput from RepAgent to Replication Server. Set this parameter at the connection level using alter connection. See “Controlling the number of commands the RepAgent executor can process”. Default: 2,147,483,647 Minimum: 1 Maximum: 2,147,483,647 |
exec_nrm_request_limit |
Specifies the amount of memory available for messages from a primary database waiting to be normalized. Set nrm_thread to ‘on’ with configure replication server before you use exec_nrm_request_limit. Default: 1,048,576 bytes (1MB) Minimum: 16,384 bytes (16KB) Maximum: 2,147,483,647 bytes (2GB) License: Separately licensed under the Advanced Services Option. See “Replication Server – Advanced Services Option”. |
exec_sqm_write_request_limit |
Specifies the amount of memory available for messages waiting to be written to an inbound queue. Default: 1MB Minimum: 16KB Maximum: 2GB |
init_sqm_write_delay |
The initial amount of time an SQM Writer should wait for more messages before writing a partially full block of messages to the queue. The SQM Writer always tries to write full blocks to the queue. If it has partially filled a block, and cannot fill it, SQM Writer waits the amount of time specified by init_sqm_write_delay before rechecking whether messages are waiting to be added to the block. If no messages exist, SQM Writer doubles the init_sqm_write_delay time. The SQM Writer continues to double the delay time until it reaches the value of init_sqm_write_max_delay. At this point, SQM Writer writes the partially full block. See “Setting the amount of time SQM Writer waits”. Default: 100 milliseconds |
init_sqm_write_max_delay |
The maximum amount of time an SQM Writer thread should wait for more messages before writing a partially full block of messages to the queue. See the description of init_sqm_write_delay for more information. See also “Setting the amount of time SQM Writer waits”. Default: 1,000 milliseconds |
mem_reduce_malloc |
Enable to allocate memory in larger chunks, which reduces the number of memory allocations and leads to improved Replication Server performance. Default: off License: Separately licensed under the Advanced Services Option. See “Replication Server – Advanced Services Option”. |
md_sqm_write_request_limit |
Specifies the amount of memory available to the Distributor for messages waiting to be written to the outbound queue.
Default: 1MB Minimum: 16K Maximum: 2GB |
memory_limit |
The maximum total memory the Replication Server can use, in megabytes. Values for several other configuration parameters are directly related to the amount of memory available from the memory pool indicated by memory_limit. These include exec_nrm_request_limit, exec_sqm_write_request_limit, md_sqm_write_request_limit, queue_dump_buffer_size, sqt_max_cache_size, sre_reserve, and sts_cachesize. Default: 2,047 For 32-bit Replication Server:
For 64-bit Replication Server:
If additional memory allocation exceeds the value for memory_limit that you specify, Replication Server enlarges memory_limit by ten percent each time memory_limit is exceeded. However, the value of memory_limit is restored to the value you set after Replication Server restarts. If the value you set is larger than 2,047, downgrading resets the value to 2,047 to protect against overflow. |
nrm_thread |
Enables the NRM thread which Replication Server can use to normalize and pack Log Transfer Language (LTL) commands in parallel with parsing by the RepAgent Executor thread. Parallel processing by the NRM thread reduces the response time of the RepAgent executor thread. The NRM thread is a thread split from RepAgent executor thread. Use the configure replication server command to set nrm_thread to on before you use exec_nrm_request_limit. Default: on License: Separately licensed under the Advanced Services Option. See “Replication Server – Advanced Services Option”. |
rec_daemon_sleep_time |
Specifies the sleep time for the recovery daemon, which handles “strict” save interval messages in warm standby applications and certain other operations. See “Setting wake up intervals”. Default: 2 minutes |
smp_enable |
Enables symmetric multiprocessing (SMP). Specifies whether Replication Server threads should be scheduled internally by Replication Server or externally by the operation system. When Replication Server threads are scheduled internally, Replication Server is restricted to one machine processor, regardless of how many may be available. Values are “on” and “off.” See “Making SMP more effective”. Default: on Upgrading or downgrading does not change the value you set. |
sqm_cache_enable |
Indicates whether to enable SQM caching and large I/O in a stable device. Default: on |
sqm_cache_size |
Indicates the number of pages in cache where size of a page is specified by sqm_page_size. Default: 16 |
sqm_page_size |
Indicates the number of blocks in a page. Sets server-wide stable queue page size in blocks per page. Enclose page sizes in single quotes or double quotes. For example, setting page size to 4 instructs Replication Server to write to the stable queue in 64K chunks. Configuring the page size also sets the I/O size of Replication Server. The range is 1 to 64. Default: 4 |
sqm_recover_segs |
Specifies the number of stable queue segments Replication Server allocates before updating the RSSD with recovery QID information. See “Specifying the number of stable queue segments allocated”. Sybase recommends that you increase the value of sqm_recover_segs to improve performance. Default: 1 Minimum: 1 Maximum: 2,147,483,648 |
sqm_seg_prealloc |
Enables or disables the segments preallocation settings. Default: on |
sqm_write_flush |
Specifies whether or not writes to memory buffers are flushed to the disk before the write operation completes. Values are “on,” “off,” and “dio”. See also “Stable devices: considerations.” Default: on |
sqt_init_read_delay |
The length of time an SQT thread sleeps while waiting for an SQM read before checking to see if it has been given new instructions in its command queue. With each expiration, if the command queue is empty, SQT doubles its sleep time up to the value set for sqt_max_read_delay. Default: 1 milliseconds (ms) Minimum: 0 ms Maximum: 86,400,000 ms (24 hours) |
sqt_max_cache_size |
Maximum SQT cache memory, in bytes. See “Sizing the SQT cache”. For 32-bit Replication Server:
For 64-bit Replication Server:
If the value you set is larger than 2,147,483,647 bytes, downgrading resets the value to 2,147,483,647 bytes to protect against overflow. |
sqt_max_read_delay |
The maximum length of time an SQT thread sleeps while waiting for an SQM read before checking to see if it has been given new instructions in its command queue. Default: 1 ms Minimum: 0 ms Maximum: 86,400,000 ms (24 hours) |
sts_cachesize |
The total number of rows that are cached for each cached RSSD system table. Increasing this number to the number of active replication definitions prevents Replication Server from executing expensive table lookups. Monitor whether the STS cache is too small by reviewing counter 11008 – STSCacheExceed or examining the Replication Server log for warnings that rows have been removed from the STS cache. See “Caching system tables”. Default: 100 |
sts_full_cache_system_table_name |
Specifies an RSSD system table that is to be fully cached. Fully cached tables do not require access to the RSSD for simple select statements. Default: rs_columns, rs_functions, rs_objects, and rs_repobjs are fully cached. Sybase recommends that you cache these tables to improve performance. See “Caching system tables” for a list of RSSD tables that can be fully cached. |
sub_daemon_sleep_time |
Number of seconds the subscription daemon sleeps before waking up to recover subscriptions. The range is 1 to 31,536,000. See“Setting wake up intervals”. Default: 120 seconds |
sub_sqm_write_request_limit |
Specifies the memory available to the subscription materialization or dematerialization thread for messages waiting to be written to the outbound queue. Default: 1MB Minimum: 16K Maximum: 2GB |
When you execute the command to change the block size, Replication
Server automatically shuts down. You must include the “with shutdown” clause
after specifying the block size. 