Broker Server Configuration Parameters
allow-unsafe-renegotiation
Specify 1 to force the Broker to allow legacy insecure renegotiation between the SSL enabled server and client. It is recommended you disable insecure renegotiation. Enabling insecure renegotiation may cause security vulnerability in the client-server applications. The default is 0 (disabled).
allow-pre-acked-on-browse
Specify 0 to disable allowing the tentatively pre-acknowledged documents . Default is 1 (enabled).
assert-config
Specify a comma separated list of options to set the assert options in the following format:
assert-config=option=value,option=value
The value for an option can be either 0 or 1.
List of assert options you can set:
crash-checks crash-preconditions crash-expensivechecks crash-postconditions never-crash never-report report-checks report-expected report-expensivechecks report-preconditions report-postconditions If you enable the report related assert options, Broker writes the assert messages to the Broker error log file (diagnostic log).
If you enable the crash related assert options, Broker performs additional checks. Broker crashes and creates core files if any of the run-time checks fail.
If you set never-report to 1, Broker will override all the report related assert options. If you set never-crash to 1, Broker will override all the crash related assert options. For example, if never-crash=1, crash-preconditions=1, Broker will not crash if a pre-condition run-time check fails and will not write the assert messages to the Broker error log file.
Types of checks that Broker can perform during run-time:
Pre-condition check on the data incoming to a function
Expected check on the expected value of a run-time data
Post-condition check on a function just before returning
Expensive check or process intensive checks on the correctness of the run-time data. Process intensive checks affects the performance.
The default is never-report=0,never-crash=1,report-preconditions=1,crash-preconditions=1,report-checks=1,crash-checks=1,report-expected=1,report-expensivechecks=1,crash-expensivechecks = 1,report-postconditions=1,crash-postconditions=1.
async
This argument specifies the Broker Server to write data to disk asynchronously. To enable the asynchronous write mode, specify the async argument in the storage session parameters, session-config and session-data. For example, sessionconfig=qs:///var/opt/BrokerStorage/BrokerConfig.qs?async
auditlog-dir
Specify the location and the name of the audit log directory. If you change the file name or location, include the full path. If you have enabled audit logging, but did not specify the audit log directory, Broker creates the audit logs in the auditlogs directory under the Broker Server’s data directory.
auditlog-enabled
Specify 0 to disable audit logging. The default is 1 (enabled).
auditlog-errorAction
Specify 1 to enable the audit logging error action. This parameter specifies whether or not to perform an operation if there is an error during audit logging. The default is 0 (disabled). For example, consider that the server audit logging is enabled (auditlog-enabled=1), auditlog-errorAction=1, and the territory modification operation is defined for audit logging (auditlog-operations=10). If for some reason the territory modification operation cannot be logged due to audit log file failure, directory creation failure, or any other error, the territory modification operation will be discarded because audit logging is not possible. If you set auditlog-errorAction=0, irrespective of the audit logging success or failure, the territory modification operation will be performed.
auditlog-maxFileSize
Specify the maximum size of audit log that the Broker Server can create for audit logging before it creates a new audit log. You can specify the values in kilobytes (K), megabytes (M), and gigabytes (G). For example,
auditlog-maxFileSize=200K
auditlog-maxFileSize=20M
auditlog-maxFileSize=2G
The maximum log file size is 2 gigabytes. The default is 20M (20 megabytes).
auditlog-maxWriteCache
Specify the number of audit records that can be cached in memory before they are written to the audit log file. The audit records are flushed from the cache and written to the audit file at a regular time interval specified by the auditlog-writeInterval parameter or when the number of audit records cached reaches the value specified in the auditlog-maxWriteCache parameter. When the Broker Server shuts down, all the audit records collected are written to the log, regardless of the cache size. You can disable the audit log caching by setting this parameter to 1. If you disable the audit log caching, Broker writes the audit records to the audit log file as and when they are generated. The default is 500.
auditlog-operations
Specify the server operations you want to audit when audit logging is enabled.
CONNECTION = 0
SESSION = 1
SERVER MODIFY = 2
SERVER SECURITY = 3
SERVER START STOP = 4
BROKER MODIFY = 5
DOCTYPE MODIFY = 6
CLIENTGROUP MODIFY = 7
CLIENTGROUP SECURITY = 8
GATEWAY MODIFY = 9
TERRITORY MODIFY = 10
CLIENT QUEUE = 11
For example, if auditlog-operations=1 4 6, the audit logging for session creation/deletion, server start/stop, and event-type modifications will be enabled. Other options such as gateway modifications and document type modifications will not be audited by the server. The default values are 2 3 4 5 6 7 8 9 10 11. Only the Broker Server connections and sessions are not logged by default.
auditlog-writeInterval
Specify the time interval in seconds for flushing the audit records from the cache and writing these records to the audit log file. The default is 30 seconds.
auto-restart
Specify 1 to enable automatic Broker Server restart by Broker Monitor whenever Broker Server goes down. Specify 0 to disable automatic Broker Server restart. The option to disable automatic Broker Server restart is useful if you want to collect the diagnostic information before restarting the Broker Server that had abruptly stopped. The default is 1 (enabled).
batchmode
Specifies the batch mode for the asynchronous disk writes. The default value for batchmode depends on the async argument. If you specify asynchronous write, batching is disabled. If you do not specify asynchronous write, Broker's heuristic is used for batching. You can configure the storage sessions to write to disks in batches by specifying the storage session URL and the batch mode in the session-config or session-data parameters.
Valid values for batchmode are:
1 - Enable batching
2 - Disable batching
3 - Use
Broker's heuristic
For example, if session-data=qs:///var/opt/BrokerStorage/BrokerData.qs?async,max_cache_size=512, asynchronous write is enabled and the batchmode is not set. In this case, Broker disables batching.
If session-data=qs:///var/opt/BrokerStorage/BrokerData.qs?fast_restart=10,max_cache_size=512, asynchronous write and batchmode are not set. In this case, Broker's heuristic is used.
If sessiondata=qs:///var/opt/BrokerStorage/BrokerData.qs?batchmode=1, batching is always on.
basic-auth-cfg-file
Specify the location of the basic authentication configuration file, basicauth.cfg. For example, set basic-auth-cfg-file= webMethods Broker_directory\data\awbrokersversion\default\basicauth.cfg.
broker-ipaddress
Specify the IP address for Broker Server port binding. By default, the Broker Server ports bind to all the available IP interfaces on the system.
bypass-authentication
Specify 1 to temporarily bypass checking user credentials to connect to the Broker Server. Default is 0.
cbtrace-size
Specify the number of Broker trace records to be dumped. Broker traces are runtime traces generated by Broker. These traces are automatically written to cbtrace.store file whenever a Broker process stops abruptly. The default is 2000.
check-crl-all
Specify 1 to enable CRL (Certificate Revocation List) checking for the entire certificate chain in the SSL certificate. The default is 0 (disabled). When check-crl-all=0, only the first certificate is checked against CRL.
confirmed-pre-acknowledgement-timeout
Specify the maximum time in seconds a Broker in a cluster holds a confirmed pre-acknowledgement before discarding it. This parameter setting is required for cleaning up the accumulated confirmed pre-acknowledgements in a cluster Broker, which never receives the published messages. The default is 600 (10 minutes).
connection-rcvbuf-size
Specify the TCP/IP receive buffer size in bytes. The maximum and minimum values are defined by the TCP/IP receive buffer size supported by the host machine of the Broker Server. Increasing this value may result in better performance on a high latency network. The default value is either the system default value or 524288 (512 KB), whichever value is higher.
connection-sndbuf-size
Specify the TCP/IP send buffer size in bytes. The maximum and minimum values are defined by the TCP/IP send buffer size supported by the host machine of the Broker Server. Increasing this value may result in better performance on high latency network. The default value is either the system default value or 524288 (512 KB), whichever value is higher.
corefiles-retained
Specify the limit for retaining the core files of the Broker Server in case of a crash. The recommended number is less than three because the core files consume a lot storage space. If the Broker Server is frequently dumping core, the production or test environment might cause shortage of storage space.
description
Specify a brief description for the Broker Server, if required. The default is an empty string.
diag
Specify 1 to enable diagnostic logging. It is recommended that you enable diagnostics logging only when you have to monitor the Broker Server behavior or troubleshoot an abnormal behavior of Broker Server. Use the extra-args and redirect-output arguments for diagnostic purpose. The default is 0 (disabled).
disable-activity-traces
Specify 1 to disable the activity traces of Broker. The default is 0 (the activity traces are enabled).
enable-fips-mode
Specify 1 to enable FIPS mode for Broker Server on the supported platforms. The default is 0 (disabled).
event-checksum
Specify 1 to force Broker to perform event checksum during publish. The default is 0 (disabled).
eventlog
Specify 0 to disable event logging on Windows. The default is 1 (enabled). View the Windows event log through the Windows Event Viewer.
executable
Specify the location of the
Broker Server binary. It is recommended that you update the change in the
Broker binary location using the
server_config utility. If you edit this parameter, make sure you update the awbrokermon.cfg file to avoid unpredictable behavior of
Broker. To update the location of the
Broker binary, remove the
Broker Server (do not delete), then add (do not create) the
Broker Server with the
-e <new full path of the binary> option to update the new location of the
Broker binary. For more information, see
Broker Server Configuration Utility.
extra-args
This parameter is used to pass the command line arguments. You can use this parameter to pass a command line arguments through the awbroker.cfg file to enable diagnostic and debugging.
Use extra-args along with redirect-output to collect information about Broker operations for diagnostic purpose in the file specified by redirect-output. The table below lists the common arguments of extra-args.
Argument Name | Specifies... |
cqueue | Client queue operations |
deliver | Delivery operations |
event | Events |
fqueue | Forward queue operations |
m1op | Multi-Broker protocols |
mbconnect | Multi-Broker connect events |
mbjoin | Territory or cluster join operations |
mbleave | Territory or cluster leave operations |
mbreach | Multi-Broker connectivity |
operation | API calls |
operationv6 | JMS and C# API calls |
pio | Parallel channel diagnostic information |
preack | Pre-acknowledgements |
result | API call result |
resultv6 | JMS and C# API call result |
connect | TCP/IP socket connect operation |
ssl | Monitoring SSL connect and disconnect operations |
awssl | Monitoring SSL handshake operations |
timer | Broker timer setting |
tx | Transactions |
For example, if you want to enable the JMS API diagnostic traces with SSL monitoring, set extra-args=-blah +operationv6 +resultv6 +ssl +awssl
fast_restart
Specifies the portion of the log file that must be played during run-time so that Broker restart is faster. Broker stores the guaranteed documents in the log files before storing these documents in the disk. Whenever Broker restarts, it must first play the log file. If the log file contains a lot of uncommitted data, storing this data will take a long time.
For example, if the log file size is 1GB, on an average, Broker will move 512MB of data from the log file to the disk every time Broker restarts. You can use the fast_restart argument to specify Broker to write the log file data to the store file more often so that during the next restart, there is fewer data to be moved from the log file to the store file.
Let us consider that the log file size is 1GB, and you have set fast_restart=4, then the entire log file will be played in four parts. That is Broker writes only 250 MB (1GB/4) of data to the disk at a time. In this case, at any given time, there will not be more then 250 MB of uncommitted data remaining in the log file during the next Broker restart. Broker would need to write 128MB of data on an average on each restart.
Set the fast_restart argument as shown below:
session-data=qs:///var/opt/BrokerStorage/BrokerData.qs?async,fast_restart=10
Be cautious while setting this argument. When the throughput of guaranteed documents is high, if you configure a small log file to play very often (for example, fast_restart=100 for a 512MB log file), you do not optimize on the usage of the argument. By default, fast_restart is disabled.
file-encoding
Specify 1 to encode the configuration file. By default, there is no encoding.
filter-collation-locale
Specify the locale, which the Broker Server should use while comparing strings during subscription filter evaluation. If you specify null, no locale is used. By default, Broker Server uses the system locale.
forget-lost-transaction-timer-interval-seconds
Specify the interval in seconds between two checks. The default is 600 seconds (10 minutes).
forget-lost-transaction-time-days
Specify the age in days when transactions was heuristically completed. The default is 10 days.
forget-lost-transaction-batch-size
Specify the number of heuristically completed transactions to be deleted in one attempt. Default is 100.
gateway-broker-req-events
Specify the limit for the number of events that can be batched for a gateway exchange. This value should not be more than the value of max-recv-events. The default is 20. Increasing the batch size might help the throughput if small documents are transferred across the (WAN Wide Area Network). Only if you have to transfer very large documents between Brokers, it is recommended that you set the batch size to a small value.
hostname
Specify the name of the host machine on which the Broker Server is installed. The default is localhost. This option overrides the typical reverse IP lookup for the system. The configured Broker presents its hostname to the requesting Broker for multi-Broker operations and the reverse host name lookup is not performed.
internal
Specify 0 to disable the logging of system messages to the internal logmsgs file. The default is 1 (enabled).
license-key
Specify the location of the license file. If the license-key file is missing or if it is invalid, Broker Server writes an error to the journal log and exits. You cannot start Broker Server if the license-key file is missing or invalid. If the license has expired, Broker Server will start, but it will not accept any documents that clients publish (clients can continue to retrieve documents that have already been published). Broker Server writes a message to the system log to indicate that it is running under an expired license.
log-alert
Specify 0 to disable the logging of alert messages generated by the server. The default is 1 (enabled).
log-info
Specify 0 to disable the logging of information messages generated by the server. The default is 1 (enabled).
log-warning
Specify 0 to disable the logging of warning messages generated by the server. The default is 1 (enabled).
max_cache_size
Specify the limit for memory that Broker Server can use to cache queue storage data. You define the value for max_cache_size using the session-config or session-data parameters. Setting the max_cache_size argument ensures that some of the storage data is cached in memory for faster storage lookup. Increasing the value of max_cache_size might improve Broker performance because the storage lookup might occur on the cache rather than on the disk.
memory-alert-threshold
Specify the threshold value in percentage (%) of available memory, if the threshold is exceeded, all publish requests are denied. The default is 90.
memory-warn-threshold
Specify the threshold value in percentage (%) of available memory, if the threshold is exceeded, a warning is logged in the server.log file. The default is 80.
max-diag-log-file-size
Specify the maximum size of the diagnostic log file in bytes. The log file is renamed to diag.log.old once the maximum log file size is reached. Default value is 10485760 (10 MB).
max-log-file-size
Specify the maximum size of the basic authentication log file in bytes. The log file is renamed with the suffix .old once the maximum log file size is reached. The old file name is basicauth.log.old unless overridden with a different file name in basicauth.cfg. Default value is 10485760 (10 MB).
max-memory-size
Specify the main memory limit in megabytes for the Broker Server to store documents. For example, max-memory-size=4096 will limit the Broker memory usage to 4GB. When this memory limit is reached, the Broker Server stops accepting documents. When the max-memory-size parameter is set, Broker Server monitors the main memory that it is using for document storage. If the size of the incoming document plus the total memory that is already in use exceeds the max-memory-size limit, Broker Server rejects the document and returns an "out of memory" error to the client. If max-memory-size is not specified (that is, this parameter is not including in the Broker Server's configuration file), Broker Server does not limit the memory usage, and will accept documents even though there might not be sufficient memory to process them.
max-open-transaction-per-client
Specify the number of open transactions that a client can have before Broker rejects creation of any new transaction for the client. Default is 1000.
max-open-transaction-per-broker
Specify the number of open transactions that a Broker can have before Broker rejects creation of any new transaction for any client in Broker. Default is 1000.
max-recv-events
Specify the maximum number of events that can be requested in a single request. The default is 160.
max-send-events-size
Specify the limit for the total size of events that can be sent by the Broker in a single request. The default is 131072 (128 KB).
max-server-log-file-size
Specify the maximum size of the server log file in bytes. Minimum value of this parameter is 1 MB. The default value is 10 MB.
max-worker-threads
Specify the limit the number of worker threads per server running on Windows. The default is 32. This parameter is not applicable on UNIX. On UNIX, Broker Server creates a new worker thread as and when it is required.
port
Specify the base port number of Broker Server. If you want to use SSL, make sure that the ports with numbers baseport-1 and baseport-2 are available. The default is 6849. It is recommended that you use server_config to change the port (by removing and adding the server). Directly editing the value of this parameter can result in unpredictable behavior on Windows as the port number might be a part of key in Windows Registry.
pre-acknowledgement-timer-interval
Specify the time interval in seconds for checking the pre-acknowledgement timeout status in a cluster Broker. The checks are done until the time specified by the tentativepre-acknowledgement-timeout parameter is reached. The timer works only for active sessions. So, if a client is disconnected from the durable queue, the timer does not work. The time-out of tentative pre-acknowledgement works in two phases to account for slow subscribers. Specify a value less than half the value of the tentativepre-acknowledgement-timeout parameter. If you specify a very small value, Broker checks the time-out status frequently. If you specify a very large value, Broker might not detect the time-out effectively. The default is 10 (10 seconds).
preallocate-memory
Specify 1 to enable the preallocate-memory parameter, if you want Broker Server to allocate the memory specified by max-memory-size when it starts. If the Broker Server cannot obtain the specified memory size during startup, it will immediately exit.
pub-net-address-in-deprecated-format
Specify 1 to retrieve the IP address from the pubNetAddr envelope field in the old six-byte format (deprecated format). The default is 0, where the IP address from the pubNetAddr envelope field is retrieved in the string format.
pub-net-address-in-envelope
Specify 1 to make the Broker insert the publisher's IPv4 or IPv6 address in the event/document envelope field, pubNetAddr. The default is 0 (disabled).
queue-cleanup-enable
Specify 1 to enable deletion of expired volatile documents from the client queues and forward queues if the total size of the expired volatile documents is equal to or greater than the memory size specified in the queue-cleanup-threshold parameter. If queue-cleanup-enable=0, when a client tries to retrieve a document from the queue, Broker will delete the volatile documents for which the time to live has elapsed. The default is 0 (disabled).
queue-cleanup-threshold
Specify the memory limit (in MB) for storing the expired volatile documents. If the queue-cleanup-enable parameter is set to 1, Broker will delete the expired volatile documents when the queue-cleanup-threshold limit is reached. The value of the queue-cleanup-threshold parameter specifies the total size of the volatile documents in all the queues of the Broker Server instance. For example, to delete the expired volatile documents when their total size exceeds 2500 MB, specify queue-cleanup-threshold=2500. When determining the memory size, consider the queue usage. If you provide a very high threshold, the queues might get overloaded until the Broker deletes the expired documents. If you provide a lower threshold, Broker checks the queues frequently even if there are no expired documents in the queues. The minimum value allowed for the queue-cleanup-threshold parameter is 1 MB. The default is 1024 (1024 MB).
rbroker-max-send-events-size
Specify in bytes the message file size or the batch size limit that the remote Broker must use while sending messages to other Brokers in one transaction. If the network bandwidth is high, set this parameter to a higher value. The default is 16 MB.
rbroker-parallelchannel-delayed-close
Specify 1 to disable delay in closing parallel channels by two seconds. The default is 1 (enabled).
Specify 0 to disable delay in closing remote broker parallel channels by two seconds. This option is applicable only when remote broker parallel channel is enabled between territory, gateway, or cluster host. The default is 1 (enabled).
rbroker-parallelchannel-count
Specify the number of parallel channels the remote Broker can request while communicating with another Broker. Valid value is an integer greater than 1. The default is 5.
rbroker-parallelchannel-enabled
Specify 1 to enable parallel channels for message communication between a remote Broker in a territory, gateway, or a cluster with another Broker. The default is 0 (disabled).
rbroker-recovery-restart-forwarding-enabled
Specify 1 to enable the Broker Server to reconnect to the remote Broker in case of partial processing of received events. The default is 0 (disabled).
rbroker-select-different-join-broker
By default, the joining Broker selects the most compatible Broker from a territory's remote Broker list during territory join operation . Specify 0 to disable auto-selection; you can then select a Broker of your choice during the territory join operation.
rbroker-streaming-ack-timeout
Specify the maximum time in seconds a Broker must wait before sending an acknowledgement. Set this parameter only if you have enabled streaming between remote Brokers. The default is 30 seconds. If you set rbroker-streaming-ack-timeout=0, the acknowledgement timeout is disabled, the forward queue of the sending Broker might hold a few unacknowledged documents unnecessarily for a longer time, and it would seem as though the documents are stuck. When streaming is enabled between remote Brokers, Broker sends an acknowledgement when either the broker-streaming-ack-timeout or rbroker-streaming-window-size parameter value is reached.
rbroker-streaming-enabled
Specify 1 to enable streaming in Broker Server. The default is 0 (Streaming is disabled). When streaming is enabled, the number of calls between two Brokers in territory or gateway is reduced. Streaming might help when you are transferring small documents using remote Brokers that are separated by a high latency Wide Area Network (WAN). Increasing the value of the connection-sndbuf-size and connection-rcvbuf-size parameters might improve the throughput on a high latency network.
rbroker-streaming-window-size
Specify the maximum number of documents a Broker must receive before sending an acknowledgement. Set this parameter only if you have enabled streaming between remote Brokers. Valid values are 1 to 1000. Increasing this value may result in better performance on a high latency network. The default is 1000. When streaming is enabled between remote Brokers, Broker sends an acknowledgement when either the broker-streaming-ack-timeout or rbroker-streaming-window-size parameter value is reached.
redirect-output
Specify the name (not the full path) of the log file to which the Broker Server's run-time console logs must be redirected.
remote-broker-req-events
Specify the limit for the number of requested events that can be batched during a remote Broker exchange. This value should not be more than the value of max-recv-events. The default is 20.
session-config
Specify the URL for the storage session configuration. You can specify additional arguments such as async, batchmode, fast_restart, and max_cache_size. For example, session-config=qs:///var/opt/BrokerStorage/BrokerConfig.qs?async
session-data
Specify the URL for the storage session data. You can specify additional arguments such as async, batchmode, fast_restart, and max_cache_size. For example, session-data=qs:///var/opt/BrokerStorage/BrokerData.qs?max_cache_size=512,async
snmp
Specify 1 to enable SNMP traps. The default is 0 (disabled).
ssl-accept-timeout
Specify the time-out time in milliseconds while accepting new SSL connections. The default is 5000 (5 seconds).
stop-queue-scan-on-pubid
Specify 0 if you want the Broker to continue scanning a queue even though a session encounters a document that cannot be retrieved because of the "order by publisher" condition. It is recommended that you specify stop-queue-scan-on-pubid=1 to avoid performance issues while scanning large queues. Default is 1 (enabled). For example, consider a Broker queue contains Doc1(Publisher1), Doc2(Publisher2), Doc3(Publisher1), Doc4(Publisher2)... If client1 retrieves Doc1 and Doc2 and if the acknowledgement is pending for these documents, client2 will stop scanning the queue at Doc3 if stop-queue-scan-on-pubid=1. If stop-queue-scan-on-pubid=0, client2 would continue scanning the queue looking for a document that is not published by the publishers already being catered by client1.
storage-max-cache-size
This parameter has been deprecated. If storage-max-cache-size parameter is specified in the configuration file, it will be overridden by the value specified by max_cache_size.
storage-alert-threshold
Specify threshold value in percentage (%) of available storage, if the threshold is exceeded, all publish requests are denied. The default is 90.
storage-warn-threshold
Specify threshold value in percentage (%) of available storage, if the threshold is exceeded, a warning is logged in the server.log file. The default is 80.
syslog
Specify 0 to disable system logging on UNIX. The default is 1 (enabled). To understand the syslog daemon configuration and to determine the location of the log file, see the man page of "syslogd" for AIX, HP-UX, Solaris and Red Hat Enterprise Linux, or the man page of "syslog-ng" for SUSE Enterprise Server.
syslog-facility
Specify the system log facility on UNIX for the Broker Server. The valid values range from local0 to local7.
tentative-pre-acknowledgement-timeout
Specify the minimum time in seconds the Brokers in the cluster will hold the published message before sending it to the subscriber. If a Broker does not receive the confirmed message pre-acknowledgement before the specified tentative-preacknowledgement-timeout time, the Broker forwards the published message to the subscriber. If a Broker receives the confirmed pre-acknowledgement before the specified tentative-preacknowledgement-timeout time, Broker deletes the published message from the client queue. The default is 20 (20 seconds).
use-localhost
Specify 1 to set the hostname of all the remote territory Brokers and remote gateway Brokers to the local server, and use the local server for troubleshooting territory/gateway issues. This parameter is used for running all the Broker Servers on localhost for diagnostic purpose only. The default is 0.
verify-ssl-certificate-purpose
Specify 1 to enable the SSL certificate purpose check on the Broker. The default is 0.
version
Specify the version of webMethods Broker. For example, if you have installed webMethods Broker 10.5, set version=10.5.
worker-timeout
Specify the time in milliseconds for the connection worker thread to timeout. The default is 100 milliseconds. This timeout indicates how long the worker thread will wait for new data on the connection before releasing the connection and going back to the worker thread pool. Specify a large value for this parameter for large document messaging or when the client response is slow.