This is an automated email from the ASF dual-hosted git repository. schultz pushed a commit to branch 9.0.x in repository https://gitbox.apache.org/repos/asf/tomcat.git
The following commit(s) were added to refs/heads/9.0.x by this push: new b75ee12 Fix https://bz.apache.org/bugzilla/show_bug.cgi?id=62723 b75ee12 is described below commit b75ee12a4ed6724c21f1a670b5a569ff5e043e52 Author: Christopher Schultz <ch...@christopherschultz.net> AuthorDate: Tue Aug 4 16:59:34 2020 -0400 Fix https://bz.apache.org/bugzilla/show_bug.cgi?id=62723 Clarify the effects of some cluster channelSendOptions. Patch provided by Mitch Claborn. --- webapps/docs/changelog.xml | 4 ++++ webapps/docs/cluster-howto.xml | 2 ++ webapps/docs/config/cluster.xml | 34 ++++++++++++++++++++++++++++++++++ 3 files changed, 40 insertions(+) diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml index 95ddadf..1806b15 100644 --- a/webapps/docs/changelog.xml +++ b/webapps/docs/changelog.xml @@ -105,6 +105,10 @@ Clean-up / standardize the XSL files used to generate the documentation. PR provided by John Bampton. (markt) </fix> + <fix> + <bug>62723</bug>: Clarify the effects of some options for cluster + <code>channelSendOptions</code>. Patch provided by Mitch Claborn. + (schultz) </changelog> </subsection> <subsection name="Other"> diff --git a/webapps/docs/cluster-howto.xml b/webapps/docs/cluster-howto.xml index cfbfc2f..09cdb2c 100644 --- a/webapps/docs/cluster-howto.xml +++ b/webapps/docs/cluster-howto.xml @@ -218,6 +218,8 @@ should be completed:</p> Synchronous vs. asynchronous is configured using the <code>channelSendOptions</code> flag and is an integer value. The default value for the <code>SimpleTcpCluster/DeltaManager</code> combo is 8, which is asynchronous. + See the <a href="config/cluster.html#SimpleTcpCluster_Attributes">configuration reference</a> + for more discussion on the various <code>channelSendOptions</code> values. </p> <p> For convenience, <code>channelSendOptions</code> can be set by name(s) rather than integer, diff --git a/webapps/docs/config/cluster.xml b/webapps/docs/config/cluster.xml index 91e8328..12434a8 100644 --- a/webapps/docs/config/cluster.xml +++ b/webapps/docs/config/cluster.xml @@ -146,6 +146,40 @@ Tomcat cluster. These include:</p> to the order in which they were sent. </p> <p> + The various <code>channelSendOptions</code> values offer a tradeoff + between throughput on the sending node and the reliability of + replication should the sending or receiving node(s) fail. Here are + some common options. "Message" could be any message sent between nodes, + but only session-change messages are considered, here. + </p> + <p> + <code>channelSendOptions="8"</code> / <code>channelSendOptions="async"</code> + As far as the sender is concerned, the message is "sent" + as soon as it has been placed in the queue on the sender for + transmission to the other nodes. The message may not reach any or all + of the recipient nodes and may not be successfully processed on any + nodes that it does reach. This option offers the highest throughput on + the sender but the least reliability, as the triggering request will + complete without any knowledge of the success/failure of the session + replication. + </p> + <p> + <code>channelSendOptions="2"</code> / <code>channelSendOptions="use_ack"</code> + The sender will block the completion of the current request until all + of the receiving nodes have acknowledged that they have received the + message, but have not necessarily processed that message. This option + will result in lower throughput on the sending node, because the message + must be transmitted and the acknowledgement received, but the + reliability is greater than the asynchronous model. + </p> + <p> + <code>channelSendOptions="6"</code> / <code>channelSendOptions="sync,use_ack"</code> + The sender will block the completion of the current request until + all of the receiving nodes have acknowledged that they have received + <u>and</u> processed the message. This option will have the lowest + throughput (of these three) but the greatest reliability. + </p> + <p> You may also set these options as a comma separated string, e.g. "async, multicast", which will be translated into <code>Channel.SEND_OPTIONS_ASYNCHRONOUS | Channel.SEND_OPTIONS_MULTICAST</code> <br/> --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org For additional commands, e-mail: dev-h...@tomcat.apache.org