MINBUF parameter - Revision history

JAL: misc formatting

2016-08-29T18:39:01Z

misc formatting

← Older revision		Revision as of 18:39, 29 August 2016
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	<p>		<p>
	If <var>MINBUF</var> is set to a value greater than <var>[[MAXBUF parameter\|MAXBUF]]</var>, <var>MAXBUF</var> is automatically reset to the value of <var>MINBUF</var>. You do not need to set the <var>MAXBUF</var> parameter in the User 0 stream, unless you want its value to differ from the value of <var>MINBUF</var>.</p>		If <var>MINBUF</var> is set to a value greater than <var>[[MAXBUF parameter\|MAXBUF]]</var>, <var>MAXBUF</var> is automatically reset to the value of <var>MINBUF</var>. You do not need to set the <var>MAXBUF</var> parameter in the User 0 stream, unless you want its value to differ from the value of <var>MINBUF</var>.</p>
	~~<p>~~
	Refer to [[Defining the runtime environment (CCAIN)#Disk buffers and Model 204 storage\|Disk buffers and Model 204 storage]] and [[Defining the user environment (CCAIN)]] for more information on page buffers.</p>

	====For SQL processing====		====For SQL processing====
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	<p class="code">4 * (4 - 3) + (18 * 3) = 58		<p class="code">4 * (4 - 3) + (18 * 3) = 58
	</p>		</p>

			==See also==
			<p>
			For more information about page buffers: </p>
			<ul>
			<li>[[Defining the runtime environment (CCAIN)#Disk buffers and Model 204 storage\|Disk buffers and Model 204 storage]] </li>

			<li>[[Defining the user environment (CCAIN)]]</li>
			</ul>

	[[Category:System parameters]]		[[Category:System parameters]]
	[[Category:Parameters]]		[[Category:Parameters]]

JAL: add 7.7 change

2016-08-23T21:45:19Z

add 7.7 change

← Older revision		Revision as of 21:45, 23 August 2016
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	==Description==		==Description==
	<p>		<p>
	The minimum number of file page buffers that must be allocated for initialization to succeed. If this number cannot be allocated due to insufficient virtual storage, initialization is terminated.</p>		The minimum number of file page buffers that must be allocated below the bar (BTB) for initialization to succeed. If this number cannot be allocated due to insufficient virtual storage, initialization is terminated.</p>
			<blockquote class="note"><b>Note:</b> As of version 7.7 of Model 204, the value of <var>MINBUF</var> depends entirely on the setting of <var>[[NUMBUFG parameter\|NUMBUFG]]</var>, which activates buffer storage above the bar.
			<ul>
			<li>If <var>NUMBUFG</var> is greater than 0, <i>all</i> buffer pool buffers are forced above the bar — no buffers are below the bar. The <var>MINBUF</var> and <var>[[NUMBUF parameter\|NUMBUF]]</var> parameters are forced to 0, and the other parameters that affect BTB storage (<var>MAXBUF</var>, <var>SPCORE</var>, <var>LDKBMWND</var>, and <var>NLRUQ</var>) are ignored. </li>

			<li>If <var>NUMBUFG</var> is set to 0, all buffers are below the bar, and the settings of the BTB-related parameters are respected and calculated as in pre-7.7 versions. </li>
			</ul>
			</blockquote>

			===If BTB buffers are used===
	<p>		<p>
	~~Starting in Version 5~~.1, the <var>MINBUF</var> parameter is automatically set to its smallest allowable value. The minimum valid value for <var>MINBUF</var> is the number of servers (the value of the <var>NSERVS</var> parameter) plus the maximum number of pseudo subtasks (the value of <var>NSUBTKS</var> parameter), times the maximum number of open disk buffers per server (the value of the <var>MAXOBUF</var> parameter), plus fifteen, represented as follows: </p>		When BTB buffers are being used (that is, <var>NUMBUFG</var> is 0 under version 7.7 or higher, or <var>NUMBUFG</var> is any value under Model 204 prior to 7.7), the <var>MINBUF</var> parameter is automatically set to its smallest allowable value. The minimum valid value for <var>MINBUF</var> is the number of servers (the value of the <var>NSERVS</var> parameter) plus the maximum number of pseudo subtasks (the value of <var>NSUBTKS</var> parameter), times the maximum number of open disk buffers per server (the value of the <var>MAXOBUF</var> parameter), plus fifteen, represented as follows: </p>
	<p class="code">(NSERVS + NSUBTKS) * MAXOBUF + 15		<p class="code">(NSERVS + NSUBTKS) * MAXOBUF + 15
	</p>		</p>
	<p>		<p>
	~~This is a change from previous releases where the minimum allowable value of <var>MINBUF</var> was <code>(NSERVS*4)+14</code> for MP/204, and 18 otherwise. </p>~~		If <var>[[NLRUQ parameter\|NLRUQ]]</var> is set greater than 1, then the value of <var>MINBUF</var> is rounded up to a multiple of <var>NLRUQ</var>. </p>
	~~<p>~~
	~~Also starting in Version 5.1, if <var>MINBUF</var> is set to a value greater than~~ <var>[[~~MAXBUF_parameter~~\|~~MAXBUF~~]]</var>, ~~<var>MAXBUF</var> is automatically reset to~~ the value of <var>MINBUF</var>~~. Prior to Version 5.1, an error message prevented the Online from coming~~ up~~. You do not need~~ to ~~set the <var>MAXBUF</var> parameter in the User 0 stream, unless you want its value to differ from the value~~ of <var>~~MINBUF~~</var>.</p>
	<p>		<p>
	If <var>[[~~NLRUQ_parameter~~\|~~NLRUQ~~]]</var> is ~~set greater than 1, then~~ the value of <var>MINBUF</var> ~~is rounded up~~ to ~~a multiple~~ of <var>~~NLRUQ~~</var>. </p>		If <var>MINBUF</var> is set to a value greater than <var>[[MAXBUF parameter\|MAXBUF]]</var>, <var>MAXBUF</var> is automatically reset to the value of <var>MINBUF</var>. You do not need to set the <var>MAXBUF</var> parameter in the User 0 stream, unless you want its value to differ from the value of <var>MINBUF</var>.</p>
	<p>		<p>
	Refer to [[Defining the runtime environment (CCAIN)]] and [[Defining the user environment (CCAIN)]] for more information on page buffers.</p>		Refer to [[Defining the runtime environment (CCAIN)#Disk buffers and Model 204 storage\|Disk buffers and Model 204 storage]] and [[Defining the user environment (CCAIN)]] for more information on page buffers.</p>

	====For SQL processing====		====For SQL processing====
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	</p>		</p>
	<p>		<p>
	For example, if NSERVS = 4 and the number of SQL threads is 3, the recommended value of MINBUF is: </p>		For example, if <var>NSERVS</var> is 4 and the number of SQL threads is 3, the recommended value of <var>MINBUF</var> is: </p>
	<p class="code">4 * (4 - 3) + (18 * 3) = 58		<p class="code">4 * (4 - 3) + (18 * 3) = 58
	</p>		</p>

DCameron: /* Description */

2015-08-04T14:26:48Z

Description

← Older revision		Revision as of 14:26, 4 August 2015
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	This is a change from previous releases where the minimum allowable value of <var>MINBUF</var> was <code>(NSERVS*4)+14</code> for MP/204, and 18 otherwise. </p>		This is a change from previous releases where the minimum allowable value of <var>MINBUF</var> was <code>(NSERVS*4)+14</code> for MP/204, and 18 otherwise. </p>
	<p>		<p>
	Also starting in Version 5.1, if <var>MINBUF</var> is set to a value greater than <var>MAXBUF</var>, <var>MAXBUF</var> is automatically reset to the value of <var>MINBUF</var>. Prior to Version 5.1, an error message prevented the Online from coming up. You do not need to set the <var>MAXBUF</var> parameter in the User 0 stream, unless you want its value to differ from the value of <var>MINBUF</var>.</p>		Also starting in Version 5.1, if <var>MINBUF</var> is set to a value greater than <var>[[MAXBUF_parameter\|MAXBUF]]</var>, <var>MAXBUF</var> is automatically reset to the value of <var>MINBUF</var>. Prior to Version 5.1, an error message prevented the Online from coming up. You do not need to set the <var>MAXBUF</var> parameter in the User 0 stream, unless you want its value to differ from the value of <var>MINBUF</var>.</p>
	<p>		<p>
	If <var>NLRUQ</var> is set greater than 1, then the value of <var>MINBUF</var> is rounded up to a multiple of <var>NLRUQ</var>. </p>		If <var>[[NLRUQ_parameter\|NLRUQ]]</var> is set greater than 1, then the value of <var>MINBUF</var> is rounded up to a multiple of <var>NLRUQ</var>. </p>
	<p>		<p>
	Refer to [[Defining the runtime environment (CCAIN)]] and [[Defining the user environment (CCAIN)]] for more information on page buffers.</p>		Refer to [[Defining the runtime environment (CCAIN)]] and [[Defining the user environment (CCAIN)]] for more information on page buffers.</p>

DCameron: /* Summary */

2015-08-04T14:22:38Z

Summary

← Older revision		Revision as of 14:22, 4 August 2015
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	<dl>		<dl>
	<dt>Default value		<dt>Default value
	<dd>Calculated using the formula: (NSERVS + NSUBTKS) * MAXOBUF + 15		<dd>Calculated using the formula: (<var>[[NSERVS_parameter\|NSERVS]]</var> + <var>[[NSUBTKS_parameter\|NSUBTKS]]</var>) * <var>[[MAXOBUF_parameter\|MAXOBUF]]</var> + 15
	<dt>Parameter type		<dt>Parameter type
	<dd>System		<dd>System
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	<dd>All		<dd>All
	<dt>Introduced		<dt>Introduced
	<dd><var class="product">Model 204 V6.1</var> or earlier		<dd><var class="product">Model 204 V9.0</var> or earlier
	</dl>		</dl>

	==Description==		==Description==
	<p>		<p>

JAL: remove Sys Man guide

2014-10-30T22:11:56Z

remove Sys Man guide

← Older revision		Revision as of 22:11, 30 October 2014
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	</dl>		</dl>
	==Description==		==Description==
	<p>The minimum number of file page buffers that must be allocated for initialization to succeed. If this number cannot be allocated due to insufficient virtual storage, initialization is terminated.</p>		<p>
	<p>Starting in Version 5.1, the MINBUF parameter is automatically set to its smallest allowable value. The minimum valid value for MINBUF is the number of servers (the value of the NSERVS parameter) plus the maximum number of pseudo subtasks (the value of NSUBTKS parameter), times the maximum number of open disk buffers per server (the value of the MAXOBUF parameter), plus fifteen, represented as follows: </p>		The minimum number of file page buffers that must be allocated for initialization to succeed. If this number cannot be allocated due to insufficient virtual storage, initialization is terminated.</p>
			<p>
			Starting in Version 5.1, the <var>MINBUF</var> parameter is automatically set to its smallest allowable value. The minimum valid value for <var>MINBUF</var> is the number of servers (the value of the <var>NSERVS</var> parameter) plus the maximum number of pseudo subtasks (the value of <var>NSUBTKS</var> parameter), times the maximum number of open disk buffers per server (the value of the <var>MAXOBUF</var> parameter), plus fifteen, represented as follows: </p>
	<p class="code">(NSERVS + NSUBTKS) * MAXOBUF + 15		<p class="code">(NSERVS + NSUBTKS) * MAXOBUF + 15
	</p>		</p>
	<p>This is a change from previous releases where the minimum allowable value of MINBUF was (NSERVS*4)+14 for MP/204 and 18 otherwise. </p>		<p>
	<p>Also starting in Version 5.1, if MINBUF is set to a value greater than MAXBUF, MAXBUF is automatically reset to the value of MINBUF. Prior to Version 5.1, an error message prevented the Online from coming up. You do not need to set the MAXBUF parameter in the User 0 stream, unless you want its value to differ from the value of MINBUF.</p>		This is a change from previous releases where the minimum allowable value of <var>MINBUF</var> was <code>(NSERVS*4)+14</code> for MP/204, and 18 otherwise. </p>
	<p>If NLRUQ is set greater than 1, then the value of MINBUF is rounded up to a multiple of NLRUQ. </p>		<p>
	<p>Refer to the ~~<var>Model 204 System Manager's Guide</var>~~ for more information on page buffers.</p>		Also starting in Version 5.1, if <var>MINBUF</var> is set to a value greater than <var>MAXBUF</var>, <var>MAXBUF</var> is automatically reset to the value of <var>MINBUF</var>. Prior to Version 5.1, an error message prevented the Online from coming up. You do not need to set the <var>MAXBUF</var> parameter in the User 0 stream, unless you want its value to differ from the value of <var>MINBUF</var>.</p>
			<p>
			If <var>NLRUQ</var> is set greater than 1, then the value of <var>MINBUF</var> is rounded up to a multiple of <var>NLRUQ</var>. </p>
			<p>
			Refer to [[Defining the runtime environment (CCAIN)]] and [[Defining the user environment (CCAIN)]] for more information on page buffers.</p>

	====For SQL processing====		====For SQL processing====
	<p>Sort operations require more buffers and other SQL DML (<var class="product">Model 204</var> SQL Data Manipulation) operations can increase disk buffer activity.</p>		<p>
	<p>The recommended formula for MINBUF with SQL depends on the number of servers (NSERVS parameter) and the number of SQL threads (numSQL):</p>		Sort operations require more buffers and other SQL DML (<var class="product">Model 204</var> SQL Data Manipulation) operations can increase disk buffer activity.</p>
	<p>If NSERVS is less than the number of SQL threads: </p>		<p>
			The recommended formula for <var>MINBUF</var> with SQL depends on the number of servers (<var>NSERVS</var> parameter) and the number of SQL threads (numSQL):</p>
			<p>
			If <var>NSERVS</var> is less than the number of SQL threads: </p>
	<p class="code">MINBUF = 18 * NSERVS		<p class="code">MINBUF = 18 * NSERVS
	</p>		</p>
	<p>If NSERVS is greater than or equal to the number of SQL threads: </p>		<p>
			If <var>NSERVS</var> is greater than or equal to the number of SQL threads: </p>
	<p class="code">MINBUF = 4 * (NSERVS - <i>numSQL</i>) + (18 * <i>numSQL</i>)		<p class="code">MINBUF = 4 * (NSERVS - <i>numSQL</i>) + (18 * <i>numSQL</i>)
	</p>		</p>
	<p>For example, if NSERVS = 4 and the number of SQL threads is 3, the recommended value of MINBUF is: </p>		<p>
			For example, if NSERVS = 4 and the number of SQL threads is 3, the recommended value of MINBUF is: </p>
	<p class="code">4 * (4 - 3) + (18 * 3) = 58		<p class="code">4 * (4 - 3) + (18 * 3) = 58
	</p>		</p>

	[[Category:System parameters]]		[[Category:System parameters]]
	[[Category:Parameters]]		[[Category:Parameters]]

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2013-08-27T16:40:10Z

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			{{Template:MINBUF parameter subtitle}}
	==Summary==		==Summary==
	<dl>		<dl>

DmeWiccan: Automatically generated page update

2013-04-23T01:51:08Z

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	<p class="code">4 * (4 - 3) + (18 * 3) = 58		<p class="code">4 * (4 - 3) + (18 * 3) = 58
	</p>		</p>
	[[Category:System ~~Parameters~~]]		[[Category:System parameters]]
	[[Category:Parameters]]		[[Category:Parameters]]

Dme: Undo revision 56889 by DmeWiccan (talk)

2013-04-19T15:18:48Z

Undo revision 56889 by DmeWiccan (talk)

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	<p class="code">4 * (4 - 3) + (18 * 3) = 58		<p class="code">4 * (4 - 3) + (18 * 3) = 58
	</p>		</p>
	[[Category:System ~~parameters~~]]		[[Category:System Parameters]]
	[[Category:Parameters]]		[[Category:Parameters]]

DmeWiccan: Automatically generated page update

2013-04-19T14:38:45Z

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	<p class="code">4 * (4 - 3) + (18 * 3) = 58		<p class="code">4 * (4 - 3) + (18 * 3) = 58
	</p>		</p>
	[[Category:System ~~Parameters~~]]		[[Category:System parameters]]
	[[Category:Parameters]]		[[Category:Parameters]]

Alex: Automatically generated page update

2013-02-28T00:56:18Z

Automatically generated page update

New page

==Summary==
<dl>
<dt>Default value
<dd>Calculated using the formula: (NSERVS + NSUBTKS) * MAXOBUF + 15
<dt>Parameter type
<dd>System
<dt>Where set
<dd>On User 0's parameter line
<dt>Related products
<dd>All
<dt>Introduced
<dd><var class="product">Model 204 V6.1</var> or earlier
</dl>
==Description==
The minimum number of file page buffers that must be allocated for initialization to succeed. If this number cannot be allocated due to insufficient virtual storage, initialization is terminated.
Starting in Version 5.1, the MINBUF parameter is automatically set to its smallest allowable value. The minimum valid value for MINBUF is the number of servers (the value of the NSERVS parameter) plus the maximum number of pseudo subtasks (the value of NSUBTKS parameter), times the maximum number of open disk buffers per server (the value of the MAXOBUF parameter), plus fifteen, represented as follows: 
(NSERVS + NSUBTKS) * MAXOBUF + 15

This is a change from previous releases where the minimum allowable value of MINBUF was (NSERVS*4)+14 for MP/204 and 18 otherwise. 
Also starting in Version 5.1, if MINBUF is set to a value greater than MAXBUF, MAXBUF is automatically reset to the value of MINBUF. Prior to Version 5.1, an error message prevented the Online from coming up. You do not need to set the MAXBUF parameter in the User 0 stream, unless you want its value to differ from the value of MINBUF.
If NLRUQ is set greater than 1, then the value of MINBUF is rounded up to a multiple of NLRUQ. 
Refer to the <var>Model 204 System Manager's Guide</var> for more information on page buffers.
====For SQL processing====
Sort operations require more buffers and other SQL DML (<var class="product">Model 204</var> SQL Data Manipulation) operations can increase disk buffer activity.
The recommended formula for MINBUF with SQL depends on the number of servers (NSERVS parameter) and the number of SQL threads (numSQL):
If NSERVS is less than the number of SQL threads: 
MINBUF = 18 * NSERVS

If NSERVS is greater than or equal to the number of SQL threads: 
MINBUF = 4 * (NSERVS - numSQL) + (18 * numSQL)

For example, if NSERVS = 4 and the number of SQL threads is 3, the recommended value of MINBUF is: 
4 * (4 - 3) + (18 * 3) = 58

[[Category:System Parameters]]
[[Category:Parameters]]