Managing record locking - Revision history

JAL: /* Controlling record locking problems */

2014-12-04T22:43:49Z

Controlling record locking problems

DCameron: /* Ensuring file integrity */

2014-09-10T14:49:20Z

Ensuring file integrity

← Older revision		Revision as of 14:49, 10 September 2014
Line 361:		Line 361:
	RELEASE RECORDS IN FD.VIN		RELEASE RECORDS IN FD.VIN

	UPD.SCR: FOR 1 RECORD ~~IN FD.~~VIN		UPD.SCR: FOR 1 RECORD ON LIST VIN
	%UPDATEID = UPDATE ID		%UPDATEID = UPDATE ID

DCameron: /* Using FIND AND RESERVE */

2014-09-10T14:35:08Z

Using FIND AND RESERVE

← Older revision		Revision as of 14:35, 10 September 2014
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	<p>The FlND AND RESERVE statement locks the current set of records in exclusive mode and therefore is recommended when executing update requests. </p>		<p>The FlND AND RESERVE statement locks the current set of records in exclusive mode and therefore is recommended when executing update requests. </p>

	<p>However, ~~Technical Support recommends~~ that you observe the following prohibitions: </p>		<p>However, it is recommended that you observe the following prohibitions: </p>

	<ul>		<ul>

DCameron at 14:25, 10 September 2014

2014-09-10T14:25:02Z

← Older revision		Revision as of 14:25, 10 September 2014
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	<p>Use ON FIND CONFLICT or ON RECORD LOCKING CONFLICT to ensure that any attempt by a FIND statement to get share access triggers the ON unit, if the records desired are already held in exclusive status by some other user. The records are held in share status during FOR EACH RECORD loop processing unless they are updated, in which case the lock is changed to exclusive. </p>		<p>Use ON FIND CONFLICT or ON RECORD LOCKING CONFLICT to ensure that any attempt by a FIND statement to get share access triggers the ON unit, if the records desired are already held in exclusive status by some other user. The records are held in share status during FOR EACH RECORD loop processing unless they are updated, in which case the lock is changed to exclusive. </p>

	<p>If the records are to be updated, ~~Technical Support recommends~~ that you use an ON RECORD LOCKING CONFLICT unit, because ON FIND CONFLICT is not triggered when the share lock is changed to exclusive. </p>		<p>If the records are to be updated, it is recommended that you use an ON RECORD LOCKING CONFLICT unit, because ON FIND CONFLICT is not triggered when the share lock is changed to exclusive. </p>

	<p>In the following example, Model 204 places the found set of records in share status but allows other users shared access as well. As a result, no one user can gain the exclusive access needed for updating. This method guarantees that data in these records cannot be changed while this procedure examines and displays them. When using this method, be sure to release the records as soon as possible to allow access by other users. </p>		<p>In the following example, Model 204 places the found set of records in share status but allows other users shared access as well. As a result, no one user can gain the exclusive access needed for updating. This method guarantees that data in these records cannot be changed while this procedure examines and displays them. When using this method, be sure to release the records as soon as possible to allow access by other users. </p>

DCameron at 14:09, 10 September 2014

2014-09-10T14:09:01Z

← Older revision		Revision as of 14:09, 10 September 2014
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	==Introduction==		==Introduction==

	Record locking controls the access and maintains the integrity of the data within the record. A record-locking conflict occurs when multiple users try to access the same records in a file for update.		Record locking controls the access and maintains the integrity of the data within the record. A record-locking conflict occurs when multiple users try to access the same records in a file for update, or when a user or users try to read a record, and another user has the record locked for update.
	<p>This topic discusses record-locking conflicts and how to prevent and manage them. </p>		<p>This topic discusses record-locking conflicts and how to prevent and manage them. </p>

Tbullock: Add SPACE

2014-09-05T18:23:42Z

Add SPACE

← Older revision		Revision as of 18:23, 5 September 2014
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	.		.
	ELSE		ELSE
	%SCR.EMSG = 'RECORD CONCURRENTLY UPDATED' -		%SCR.EMSG = 'RECORD CONCURRENTLY UPDATED ' -
	WITH 'REDO UPDATES ON REFRESHED RECORD'		WITH 'REDO UPDATES ON REFRESHED RECORD'
	IN VEHICLES CLEAR LIST VIN		IN VEHICLES CLEAR LIST VIN

Tbullock: Fix syntax errors

2014-09-05T18:21:43Z

Fix syntax errors

← Older revision		Revision as of 18:21, 5 September 2014
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	. </nowiki>		. </nowiki>
	ON FIND CONFLICT		ON FIND CONFLICT
	AUDIT 'LOCK CONFLICT WITH $RLCFILE $RLCUSR $RLCREC		AUDIT 'LOCK CONFLICT ' WITH $RLCFILE AND $RLCUSR AND $RLCREC
	READ OFC		READ OFC
	**********************************		**********************************
	WHERE OFC IS A SCREEN DEF		WHERE OFC IS A SCREEN DEF
	INCLUDED IN PROCESSING ABOVE		INCLUDED IN PROCESSING ABOVE
	**********************************		**********************************
	IF %OFC:ANSWER EQ 'Y' THEN		IF %OFC:ANSWER EQ 'Y' THEN
	RETRY		RETRY
	ELSE JUMP TO FINISH		ELSE
			JUMP TO FINISH
	END IF		END IF
	END ON		END ON
Line 201:		Line 202:
	PRINT 'END OF REPORT'		PRINT 'END OF REPORT'
	FINISH:		FINISH:
	END		END
	</p>		</p>

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	. </nowiki>		. </nowiki>
	ON FIND CONFLICT		ON FIND CONFLICT
	AUDIT 'RECORD LOCKING CONFLICT CANCELLED' WITH -		AUDIT 'RECORD LOCKING CONFLICT CANCELLED ' WITH -
	$RLCFILE $RLCUSR $RLCREC		$RLCFILE AND $RLCUSR AND $RLCREC
	JUMP TO PRT.ERROR		JUMP TO PRT.ERROR
	END ON		END ON
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	PLACE RECORDS IN FD.ACCT ON LIST ACCTS		PLACE RECORDS IN FD.ACCT ON LIST ACCTS
	********************		********************
	RELEASE THEM		RELEASE THEM
	********************</nowiki>		********************</nowiki>
	RELEASE RECORDS IN FD.ACCT		RELEASE RECORDS IN FD.ACCT
Line 303:		Line 304:
	%FILE = $RLCFILE		%FILE = $RLCFILE
	%USER = $RLCUSR		%USER = $RLCUSR
	AUDIT 'RECORD LOCKING CONFLICT DURING DEPT PROCESSING' WITH %RECORD %FILE %USER		AUDIT 'RECORD LOCKING CONFLICT DURING DEPT PROCESSING ' WITH %RECORD AND %FILE AND %USER
	<nowiki>*******************		<nowiki>*******************
	SET COUNTER		SET COUNTER
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	%UPDATEID = UPDATE ID		%UPDATEID = UPDATE ID

	<nowiki>~~*~~**********************		<nowiki>************************
	FILL SCREEN HERE		FILL SCREEN HERE
	************************</nowiki>		************************</nowiki>

Tbullock: Join two lines so it can compile.

2014-09-05T00:26:01Z

Join two lines so it can compile.

← Older revision		Revision as of 00:26, 5 September 2014
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	PROMPT ' RECORD:' PROMPT RECORD		PROMPT ' RECORD:' PROMPT RECORD
	SKIP 2 LINES		SKIP 2 LINES
	PROMPT 'DO YOU WANT TO TRY AGAIN?' INPUT		PROMPT 'DO YOU WANT TO TRY AGAIN?' INPUT TRY ONEOF Y,N DEFAULT 'N'
	TRY ONEOF Y,N DEFAULT 'N'
	END SCREEN		END SCREEN
	ORLC:		ORLC:
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	%FILE = $RLCFILE		%FILE = $RLCFILE
	%USER = $RLCUSR		%USER = $RLCUSR
	AUDIT = 'RECORD LOCKING CONFLICT DURING DEPT		AUDIT 'RECORD LOCKING CONFLICT DURING DEPT PROCESSING' WITH %RECORD %FILE %USER
	PROCESSING' WITH %RECORD %FILE %USER
	<nowiki>*******************		<nowiki>*******************
	SET COUNTER		SET COUNTER

JAL: /* Controlling record locking problems */

2014-08-01T20:51:46Z

Controlling record locking problems

← Older revision		Revision as of 20:51, 1 August 2014
Line 408:		Line 408:

	<ul>		<ul>
	<li>You can avoid many conflicts by releasing records as soon as you no longer need them.		<li>You can avoid many conflicts by releasing records as soon as you no longer need them. </li>
	</li>		<li>Use a commit statement at the end of every update unit. </li>
	<li>Use a commit statement at the end of every update unit.		<li>If possible, keep update units within the same terminal I/O point. </li>
	</li>		<li>In a multi-request application, segregate updating functions from read-only functions. </li>
	<li>If possible, keep update units within the same terminal I/O point.		<li>To free pages in CCATEMP, use the CLEAR LIST statement when you no longer need the records in a list. </li>
	</li>		<li>Perform REDEFINE, RENAME, and DELETE FIELD functions during off-peak hours. </li>
	<li>In a multi-request application, segregate updating functions from read-only functions.		<li>When not using the application subsystem facility, set the ENQRETRY parameter to control the number of retries before a message is generated. </li>
	</li>		<li>Place the records you need on a list, release the records, and process from the list in situations where no updates are taking place or where updates are known not to affect the data in question. </li>
	<li>To free pages in CCATEMP, use the CLEAR LIST statement when you no longer need the records in a list.		<li>Defer index updates whenever possible. </li>
	</li>
	<li>Perform REDEFINE, RENAME, and DELETE FIELD functions during off-peak hours.
	</li>
	<li>When not using the application subsystem facility, set the ENQRETRY parameter to control the number of retries before a message is generated.
	</li>
	<li>Place the records you need on a list, release the records, and process from the list in situations where no updates are taking place or where updates are known not to affect the data in question.
	</li>
	<li>Defer index updates whenever possible.
	</li>
	</ul>		</ul>

	<p>For more information on file management, see the [[#Category:~~Model 204 files~~\|~~Rocket~~ Model 204 File Management wiki pages]]. </p>		<p>For more information on file management, see the [[:Category: File management\|Model 204 File Management wiki pages]]. </p>

	[[Category: Overviews]]		[[Category: Overviews]]

	[[Category: Application development]]		[[Category: Application development]]

ELowell: /* Introduction */

2014-06-12T20:29:38Z

Introduction

← Older revision		Revision as of 20:29, 12 June 2014
Line 2:		Line 2:

	Record locking controls the access and maintains the integrity of the data within the record. A record-locking conflict occurs when multiple users try to access the same records in a file for update.		Record locking controls the access and maintains the integrity of the data within the record. A record-locking conflict occurs when multiple users try to access the same records in a file for update.
	<p>This ~~section~~ discusses record-locking conflicts and how to prevent and manage them. </p>		<p>This topic discusses record-locking conflicts and how to prevent and manage them. </p>

	==Locking conflict example==		==Locking conflict example==

← Older revision		Revision as of 22:43, 4 December 2014
Line 403:		Line 403:

	==Controlling record locking problems==		==Controlling record locking problems==
			<p>
	<p>To control record-locking problems, keep in mind the following guidelines: </p>		To control record-locking problems, keep in mind the following guidelines: </p>

	<ul>		<ul>
	<li>You can avoid many conflicts by releasing records as soon as you no longer need them. </li>		<li>You can avoid many conflicts by releasing records as soon as you no longer need them. </li>

	<li>Use a commit statement at the end of every update unit. </li>		<li>Use a commit statement at the end of every update unit. </li>

	<li>If possible, keep update units within the same terminal I/O point. </li>		<li>If possible, keep update units within the same terminal I/O point. </li>

	<li>In a multi-request application, segregate updating functions from read-only functions. </li>		<li>In a multi-request application, segregate updating functions from read-only functions. </li>

	<li>To free pages in CCATEMP, use the CLEAR LIST statement when you no longer need the records in a list. </li>		<li>To free pages in CCATEMP, use the CLEAR LIST statement when you no longer need the records in a list. </li>

	<li>Perform REDEFINE, RENAME, and DELETE FIELD functions during off-peak hours. </li>		<li>Perform REDEFINE, RENAME, and DELETE FIELD functions during off-peak hours. </li>
	<li>When not using the application subsystem facility, set the ENQRETRY parameter to control the number of retries before a message is generated. </li>
			<li>When not using the application subsystem facility, set the <var>[[ENQRETRY parameter\|ENQRETRY]]</var> parameter to control the number of retries before a message is generated. </li>

	<li>Place the records you need on a list, release the records, and process from the list in situations where no updates are taking place or where updates are known not to affect the data in question. </li>		<li>Place the records you need on a list, release the records, and process from the list in situations where no updates are taking place or where updates are known not to affect the data in question. </li>

	<li>Defer index updates whenever possible. </li>		<li>Defer index updates whenever possible. </li>
	</ul>		</ul>

	<p>For more information on file management, see the [[:Category: ~~File management~~\|Model 204 ~~File Management~~ wiki pages]]. </p>		<p>For more information on file management, see the [[:Category: Model 204 files\|Model 204 file management wiki pages]]. </p>

	[[Category: Overviews]]		[[Category: Overviews]]

	[[Category: Application development]]		[[Category: Application development]]