TM properties

doc/src/asciidoc/ch09/transaction_manager.asc

@@ -188,4 +188,31 @@ This adds the following information to the log
   </debug>
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+* *sessions* +
+Defines the number of simultaneous sessions (Threads) used to process transactions.
+Defaults to one. It is recommended to keep the `sessions` property with a
+reasonable value commensurate the number of CPU cores of the system. A
+large number here just slows down the capacity of the system.
+
+* *max-sessions* +
+In order to deal with occasional traffic spikes (sometime caused by small
+network glitches), the TransactionManager can temporarily increase the
+number of sessions. This property defines that maximum. It defaults to
+the value set for `sessions`. For obvious reasons, `max-sessions` can't
+be less than `sessions`.
+
+* *max-active-sessions* +
+When using the TransactionManager _continuations_ feature (prepare callback
+returns `PAUSE` modifier), it is possible that a small number of sessions
+can process a large number of in-flight transactions. Those transactions
+may place in the `Context` references to live objects such as JDBC
+sessions. In order to place a cap on the number of in-flight transactions
+to avoid exhausting resources (for example a JDBC pool), this
+`max-active-sessions` property can be set. The default is 0.
+
+[TIP]
+=====
+If you're _pausing_ your transactions, please read the previous paragraph
+multiple times and make sure you understand it. 
+=====