Subject:  EVENT: Full Event Syntax (from ksdp.c) 
Creation Date:  07-APR-1997 

This is the full event specification syntax from ksdp.c
These are the source code comments.

/*  
  The syntax of  the event specification in init.ora and the SQL
  "ALTER SESSION SET EVENTS" DDL is described below.
 
  Event Specification Syntax:
 
  The parameter keyword name is "event", with its value of string
  type.   The  string value is  typically  quoted,  and  has  the
  following   syntax   (white   space   separators  are  implicit
  throughout):
 
        <event name><action>{:<event name><action>}*
 
  where:
        <event name> is a symbolic name associated with the event,
                or  optionally  an  event  number.   There  is  a
                special     name:     "immediate":      immediate
                unconditional  event, does not  wait for somebody
                to post it.
                If  a number  is specified, it is taken  to be an
                Oracle error number.  If a name is specified, the
                parser looks it up in an event name  table  if it
                is not "immediate".
 
        <action> is:
                <action keyword><action qualifiers>
 
                where:
                        <action keyword> is:
                                "trace"|"debugger"|"crash"
 
                        <action qualifiers> is:
                                <qualifier>{,<qualifier>}*
 
  Qualifier syntax depends on the action, as follows:
 
  Action "crash":
          "" (nothing, use all defaults)
        | "off" (disable crash action for this event)
        | "after <N> times" (crash after <n> occurrences of this event)
 
  Action "debugger":
          "" (nothing, use all defaults)
        | "off" (disable debugger invocation action for this event)
        | "after <n> times" (start invoking debugger on this event
                             after <n> occurrences of this event)
        | "forever" (once debugger is invoked, invoke each time
                     event occurs)
        | "lifetime <n>" (once  debugger  is invoked, invoke each
                          time for <n>  successive ocurrences  of
                          this   event,  then  disable   debugger
                          action for this event)
 
  Action "trace":
        <trace spec>{;<trace spec>}*
 
        <trace spec>:
                "name "<trace name><trace qualifier>{,<trace qualifier>}*
 
        <trace name>:
                Symbolic  name associated with  an internal trace
                id  which  is used to associate  a  trace with  a
                (context-independent) debug dump operation.
 
                A special  trace name is "context", which means a
                context-  specific trace which  does not  cause a
                debug  dump operation to  be  invoked,  but which
                instead  returns  to  the  caller who  posted the
                event and informs it whether  context tracing  is
                active  for that event, and if so, what the trace
                level is.  The trace level  is used internally by
                the dump routines to control the  level of detail
                in the dump.   By convention, the level of detail
                increases with the level  number, with the lowest
                level being  1.   The caller is then  responsible
                for invoking whatever dump operation it wants to,
                with whatever parameters are relevant.
 
                Another  special  trace  name  is   "all",  which
                expands  to  mean   all  trace  names  that  were
                declared  at  compile time through the "ksdtradv"
                macro, as well as the (last) "context" trace.
 
                If  more  than one trace  is associated  with  an
                event,   at   most   one   can   be    "context".
                Correspondingly, the last  action associated with
                an  event  posting is  to return the level number
                associated with the context-dependent trace.  The
                event   numbers  had  better  be   unique   among
                different callers.
 
        <trace qualifier>:
                  "" (nothing, use all defaults)
                | "off" (disable this trace for current event)
                | "after <n> times" (start doing this trace after <n>
                                     occurrences of this event)
                | "forever" (once this trace is activated, activate
                             it each time this event occurs)
                | "lifetime <n>" (once this trace is activated, activate
                                  it each time for <n> successive
                                  occurrences of this event, then disable
                                  this trace for this event)
                | "level <n>" (when the trace is activated the first time,
                               set its initial level to <n>.  Levels for
                               subsequent activations are determined by
                               the trace type specification below)
                | "type <trace type>" (how to modify trace level)
 
                <trace type>:
                          "increment" (increment level up to ceiling)
                        | "decrement" (decrement level down to 0 and disable)
                        | "constant"  (no change in level)
 
  Defaults:
 
        (a) action "crash"
                No delay specified - delay of 0 ie. on first event.
 
        (b) action "debugger"
                No delay specified - delay of 0 ie. on first event.
                No lifetime specified - lifetime of 1.
 
        (c) action "trace"
                No delay specified - delay of 0 ie. on first event.
                No lifetime specified - lifetime of 1.
                No level specified - level of 1 (terse).
                No type specified - type "constant"
 
        Additionally, for trace  specifications, one can  specify
        an  event named "immediate"  which is interpreted to mean
        don't wait for an event before doing the trace.  For this
        case,  no  trace   qualifiers   except  the  trace  level
        qualifier must be specified.  The  lifetime of the  trace
        is implicitly 1.
 
  A duplicate event specification with the same action supercedes
  the old specification.  Specifications of different actions for
  the same event may coexist, with  the action taken according to
  the following precedence:
 
        1. context-independent traces in order of declaration.
        2. context-specific trace.
        3. debugger call.
        4. Oracle crash.
 
  Examples:
 
  1. endtransaction crash after 3 times
 
  2. searchloop debugger lifetime 10
 
  3. aborttransaction crash off
 
  4. fatalbug trace name statetree forever,type increment; \
        name freelist lifetime 10, after 10 times
 
  5. immediate trace name cachebufs level 2; name locks; \
        name tree level7
 
  6. 2134 trace name context level 3, after 3 times, forever
 
  7. 1 trace name all:2 debug after 2 times:2 trace name context
 
  NOTE: none  of the debug facilities  are  available until after
  process has actually initialized its fixed-PGA-part (which will
  happen at connect time).
*/