Sessions - Revision history

Goff: less awkward wording

2022-03-21T21:20:00Z

less awkward wording

← Older revision		Revision as of 21:20, 21 March 2022
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	<td>Clean up timed-out sessions. If this bit is on and the X'02' bit is off, every <var>$Session_Create</var>, <var>$Session_Open</var>, <var>$Session_Close</var>, and <var>$Session_Delete</var> call cleans up timed-out sessions. This cleanup could occur well after the timeout occurred if $Session<i>xxx</i> calls are relatively infrequent.		<td>Clean up timed-out sessions. If this bit is on and the X'02' bit is off, every <var>$Session_Create</var>, <var>$Session_Open</var>, <var>$Session_Close</var>, and <var>$Session_Delete</var> call cleans up timed-out sessions. This cleanup could occur well after the timeout occurred if $Session<i>xxx</i> calls are relatively infrequent.
	<p>		<p>
	Use this option for cleaning up a timed-out session~~, but~~ it is not worth incurring the overhead of having a <var>PST</var> to do the cleanups. Since timed out sessions are now always immediately cleaned up, this bit is irrelevant. </p></td></tr>		Use this option for cleaning up a timed-out session when it is not worth incurring the overhead of having a <var>PST</var> to do the cleanups. Since timed out sessions are now always immediately cleaned up, this bit is irrelevant. </p></td></tr>

	<tr><th>X'02' </th>		<tr><th>X'02' </th>
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	</table>		</table>
	<p>		<p>
	The default value for <var>SESOPT</var> is 0, which means that timed out sessions are not cleaned up and, in fact, can still be opened after timeout, if they ~~have~~ yet to be deleted. Under the default settings, sessions are only deleted when they are timed out, a new private or public sessions is being created, and the maximum like-typed (private or public) sessions are active. In this case, the oldest like-typed session is deleted. </p>		The default value for <var>SESOPT</var> is 0, which means that timed out sessions are not cleaned up and, in fact, can still be opened after timeout, if they are yet to be deleted. Under the default settings, sessions are only deleted when they are timed out, a new private or public sessions is being created, and the maximum like-typed (private or public) sessions are active. In this case, the oldest like-typed session is deleted. </p>
	<p>		<p>
	Since a PST is now attached whenever there are any active sessions in an Online, this bit is irrelevant. The attached <var>PST</var> always actively deletes any timed-out sessions immediately. </p></td></tr>		Since a PST is now attached whenever there are any active sessions in an Online, this bit is irrelevant. The attached <var>PST</var> always actively deletes any timed-out sessions immediately. </p></td></tr>

JAL: misc cleanup

2017-10-09T21:11:23Z

misc cleanup

Show changes

Dme at 04:03, 1 October 2017

2017-10-01T04:03:03Z

← Older revision		Revision as of 04:03, 1 October 2017
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	The inactivity time for a timeout can be set at session creation time		The inactivity time for a timeout can be set at session creation time
	and changed whenever the session is closed.		and changed whenever the session is closed.

			Arguments on <var>$Session_<i>xxx</i></var> calls, and some system parameters, control the timeout value of sessions. One of these parameters, <var>[[SESMAXTO parameter\|SESMAXTO]]</var>, can be reset to ensure that all sessions have a timeout value no more than the new value of <var>SESMAXTO</var>; this can result in immediate timeout of some sessions.

	There are several system parameters that control the availability		There are several system parameters that control the availability

Goff at 04:47, 12 April 2016

2016-04-12T04:47:36Z

← Older revision		Revision as of 04:47, 12 April 2016
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	</td></tr>		</td></tr>
	<tr><th><var>SESUMAX</var>		<tr><th><var>SESUMAX</var>
	</th><td>The maximum number of private sessions that can be active for a single ~~owener~~ (userid). The default value for <var>SESUMAX</var> is 0, which means that a given userid can only have one session active at a time.		</th><td>The maximum number of private sessions that can be active for a single owner (userid). The default value for <var>SESUMAX</var> is 0, which means that a given userid can only have one session active at a time.
	</td></tr>		</td></tr>
	<tr><th><var>SESOPT</var>		<tr><th><var>SESOPT</var>

JAL2 at 20:07, 14 October 2011

2011-10-14T20:07:28Z

← Older revision		Revision as of 20:07, 14 October 2011
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	<li>[[Global and session objects\|"Global and session objects"]]		<li>[[Global and session objects\|"Global and session objects"]]
	</ul>		</ul>


			[[Category:Overviews]]

JAL2 at 19:06, 29 August 2011

2011-08-29T19:06:02Z

← Older revision		Revision as of 19:06, 29 August 2011
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	Sessions can contain both system and <var class="product">User Language</var> objects.		Sessions can contain both system and <var class="product">User Language</var> objects.
	When a session is closed, any objects associated with a session name,		When a session is closed, any objects associated with a session name,
	either via the ~~<var>~~Session~~</var>~~ keyword on a variable declaration or via a		either via [[Global and session objects#Binding global/session names to a variable\|the Session keyword]] on a variable declaration or via a
	<var>SetSession</var> method in the object class, “follow the closed session”		<var>[[Global and session objects#setsession\|SetSession]]</var> method in the object class, “follow the closed session”
	and become logically owned by the session <var>PST</var>.		and become logically owned by the session <var>PST</var>.

JAL2 at 17:02, 29 July 2011

2011-07-29T17:02:25Z

← Older revision		Revision as of 17:02, 29 July 2011
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	considered to be “owned” by the session <var>PST</var>, and so,		considered to be “owned” by the session <var>PST</var>, and so,
	where possible, <var class="product">[[SirMon]]</var> tries to indicate this ownership.		where possible, <var class="product">[[SirMon]]</var> tries to indicate this ownership.

			==See also==
			<ul>
			<li>[[Global and session objects\|"Global and session objects"]]
			</ul>

JAL2: Created page with " `Sirius Mods` provides several $functions to support sessions. A '''session''' is a workstream that might extend beyond a `Model 20..."`

2011-07-29T16:59:40Z

Created page with " <var class="product">Sirius Mods</var> provides several $functions to support sessions. A '''session''' is a workstream that might extend beyond a <var class="product">Model 20..."

New page

<var class="product">Sirius Mods</var> provides several $functions to support
sessions.
A '''session''' is a workstream that might extend beyond a
<var class="product">Model 204</var> login session and might even be transferred among multiple
<var class="product">Model 204</var> threads or users.
Sessions are especially useful for web applications that require some
context to be maintained over multiple web requests, each of which
requires a login and logout.
Sessions do not, of course, survive the cycling of the Online in which
they were established, and they cannot be passed between Onlines.

Sessions are a collection of data structures that are accessible while
the session is open and that persist as long as the session persists.
These data structures include session <var>$lists</var>, session <var>Longstrings</var>, and
session <var>XmlDocs</var>.
Sessions can also contain objects, that is, instances of a class.

Sessions can be created with <var>[[$Session_Create]]</var>, re-opened with <var>[[$Session_Open]]</var>,
closed with <var>[[$Session_Close]]</var>, and deleted with <var>[[$Session_Delete]]</var>.
Only a single session may be open at a time on a thread, and any session
that is open when a user logs off is automatically closed.
A session can only be open on a single thread at any given time.

Sessions are owned by a specific user, or they are public (in which case
they are considered to be "owned by *", that is, owned by all users).
Non-privileged users can only create, access, and delete public sessions
and those owned by themselves, that is, by their own userids.
Privileged, that is system manager or system administrator users, can
create, access, and delete public sessions and those owned by any user.

To reestablish a session between logins (or within a login), each session
requires an identifier called a '''session ID'''.
The session ID is established when the session is created, and it can be changed
as needed.
A session ID must be unique for a userid, or for an entire Online if the
session is public.

Inactive sessions, that is, those that haven't been opened in a long time,
are considered '''timed out''' and are eligible for deletion.
The inactivity time for a timeout can be set at session creation time
and changed whenever the session is closed.

There are several system parameters that control the availability
and behavior of the session feature:
<table>
<tr><th><var>SESNPRV</var>
</th><td>The maximum number of private sessions that can be active. Setting this value allocates about 160 bytes of virtual storage for each possible session. The default value for <var>SESNPRV</var> is 0, which means that no private sessions can be created.
</td></tr>
<tr><th><var>SESNPUB</var>
</th><td>The maximum number of public sessions that can be active. Setting this value allocates about 160 bytes of virtual storage for each possible session. The default value for <var>SESNPUB</var> is 0, which means that no public sessions can be created.
</td></tr>
<tr><th><var>SESUMAX</var>
</th><td>The maximum number of private sessions that can be active for a single owener (userid). The default value for <var>SESUMAX</var> is 0, which means that a given userid can only have one session active at a time.
</td></tr>
<tr><th><var>SESOPT</var>
</th><td>A bitmask parameter that controls the behavior of the session feature. The meaning of the bits are:
<table> <tr><th>X'01' </th><td>Clean up timed out sessions. If this bit is on and the X'02' bit is off, every <var>$Session_Create</var>, <var>$Session_Open</var>, <var>$Session_Close</var>, and <var>$Session_Delete</var> call cleans up timed out sessions. This cleanup could occur well after the timeout occurred if $Sessionxxx calls are relatively infrequent.
<p>
Use this option if timed-out session cleanup is desired but it is not worth incurring the overhead of having a <var>PST</var> to do the cleanups. Since timed out sessions are now always immediately cleaned up, this bit is irrelevant. </p></td></tr>
<tr><th>X'02' </th>
<td>Create a <var>PST</var> to clean up timed out sessions. If this bit is on, a <var>PST</var> is attached in the Online whenever there is an active but not open session. If a session times out, the <var>PST</var> immediately deletes the session, freeing up the <var>CCATEMP</var> pages used by the session.
<p>
Use this option if cleaning up sessions very quickly is worth the (probably slight) cost of having a <var>PST</var> to do the cleanup. </p></td></tr></table>
The default value for <var>SESOPT</var> is 0, which means that timed out sessions are not cleaned up and, in fact, can still be opened after timeout, if they have yet to be deleted. Under the default settings, sessions are only deleted when they are timed out, a new private or public sessions is being created, and the maximum like-typed (private or public) sessions are active. In this case, the oldest like-typed session is deleted.

Since a PST is now attached whenever there are any active sessions in an Online, this bit is irrelevant. The attached <var>PST</var> always actively deletes any timed-out sessions immediately.
</td></tr>
<tr><th><var>SESDEFTO</var> </th>
<td>Sets the default timeout value for a session if one is not specified in the $session_create call. The default value for <var>SESDEFTO</var> is 900, which indicates a default timeout of 900 seconds, or 15 minutes. If a session is not re-opened within the timeout value of the <var>$Session_Close</var>, it is considered timed-out and liable to deletion under control of the <var>SESOPT</var> flags, or immediately under <var class="product">Sirius Mods</var> 6.6 and later. The <var>SESDEFTO</var> setting can be overridden in many of the $SESSIONxxx functions.
</td></tr>
<tr><th><var>SESDEFOW</var>
</th><td>Sets the default open wait time value for a session if one is not specified in the <var>$Session_Open</var> call. The default value for <var>SESDEFTO</var> is 0, which means a <var>$Session_Open</var> call will not wait if the request session is in-use, that is, open by another thread.
If a session is still in-use after the open wait time, a return code of 2 is set by <var>$Session_Open</var> to indicate the problem. The <var>SESDEFOW</var> setting can be overridden in the <var>$Session_Open</var> call.
</td></tr></table>

Sessions can contain both system and <var class="product">User Language</var> objects.
When a session is closed, any objects associated with a session name,
either via the <var>Session</var> keyword on a variable declaration or via a
<var>SetSession</var> method in the object class, “follow the closed session”
and become logically owned by the session <var>PST</var>.

In addition, any objects accessible indirectly from a session name
also “follow the session.”
That is, if an object can be accessed via a session name and that
object contains a reference to another object, the latter object
also “follows the session” when the session is closed.
Because determining which objects can be accessed directly or
indirectly from a session name is very much like object
[[Global and session objects#Managing object storage|garbage collection]],
a <var>$Session_Close</var> causes garbage
collection to be performed for the invoking thread.

Many of the data structures associated with sessions are also
associated with system-wide resources such as <var>CCATEMP</var> pages,
virtual storage, record locks, <var class="product">Janus</var> threads, file locks, and
so on.
When a session is closed but not deleted, these resources are
considered to be “owned” by the session <var>PST</var>, and so,
where possible, <var class="product">[[SirMon]]</var> tries to indicate this ownership.