Special Processes, EDB File Maintenance & Compute Cycles DETAIL DESIGN. Document Number BYCOVER. July 14, Phillip Thompson

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1 Special Processes, EDB File Maintenance & Compute Cycles DETAIL DESIGN Document Number BYCOVER July 14, 1995 Phillip Thompson Information Systems & Computing Office of the President University of California

2 Page 2 Final

3 Table of Contents Introduction... 1 Overview... 2 Input Bypass Flag:... 2 Activity Generation Number... 3 EDB Generation Number... 3 Program Changes... 5 PPP PPP Attachments... 6

4 Page 1 Introduction Releases 964, Student FICA, and 988, Daily Employment Status Derivation, introduced Special Processes to the EDB Maintenance process. These Special Processes involve the updating of the System Control Record via programs PPP020 and PPP130 in ways which make the production control of other EDB Maintenance processes difficult. A Special Process during the middle of an EDB File Maintenance cycle requires a rerun of PPP020 to reset the Activity Generation Number and Bypass flag. If multiple Special Processes were run, each with an execution of PPP020, a rerun of PPP020 to reset the Activity Generation Number would be required after each Special Process. If two Special Processes were run backto-back, each with its own run of PPP020, the Set Transaction Control Number would be initialized to zero. There is no simple way to correct this problem, and "manual" intervention would be required to restart the EDB File Maintenance process. PPP130 increments the EDB Generation Number. When a Special Process occurs in the middle of a Compute cycle and updates the EDB Generation Number, that results in several possible events within the Compute process. During the Compute edit cycle it will trigger re-editing. This is not a problem, especially since with online update re-editing should be done anyway. During the Compute, in PPP390 and PPP410, a message will be issued noting the change in the EDB Generation Number. In the Base system these messages are Warning level. The local effect depends on local JCL Condition Codes and local changes to the message severity. If the EDB Generation Number is changed between PPP410 and PPP420, PPP420 issues a message and performs a soft "abend" regardless of the message severity. It has been requested that the Special Processes be changed so that other PPS processes can occur without undue oversight and intervention by production control.

5 Page 2 Overview The proposed changes affect the way in which Special Processes will update the System Control Record, i.e. the SCR table. Specifically, the handling of the EDB Generation Number (SCR_EDB_GENNUM), Input Bypass Flag (SCR_INPUT_BYPASS) and the Activity Generation Number (SCR_ACTVTY_GENNUM) will be changed. The latter, in turn, will affect the handling of the Set Transaction Control Number (SCR_SET_CNTRL_NUM). Input Bypass Flag: The Input Bypass Flag is a vestigial control mechanism left from when PPP120 performed both EDB File Maintenance and Periodic Maintenance. It is used in PPP020, PPP050 and PPP120. It is set "on" in PPP020 when either Periodic Maintenance or a Special Process is requested. This indicates that no input transactions are expected to be processed. In PPP050, if the Input Bypass Flag is "on", PPP050 issues message (Base severity of 8) and stops. The message text is: OPER - NO DATABASE MAINTENANCE EXPECTED THIS RUN PPP120 contains logic that implies it can run if the Input Bypass Flag is "on", i.e. it checks its value in several locations. One approach would be to remove all references to SCR_INPUT_BYPASS from the three programs. It would be simple to do in PPP020 and PPP050. It would be more complicated in PPP120 because in most cases the reference is contained in a compound IF condition statement. There is also the issue of DDL work and INCLUDE's for the SCR row across the application. It is also possible that running PPP120 without input might be desirable for some future purpose, and thus the flag might serve a purpose (though it seems more likely that such a future purpose would more likely use the Special Process path). PPP020 will be changed to not update the Input Bypass Flag when a Special Process is being requested. If PPP020 is run to request Periodic Maintenance the Input Bypass Flag will continue to be turned on. If Periodic Indicator Initialization is requested, the Input Bypass Flag will continue to be turned off. And, if File Maintenance is requested, i.e. neither Period Indicators or the Special Process Indicator are on, then the Input Bypass Flag will continue to be turned off as it is now. If a Special Process is being requested, the Input Bypass Flag will remain unchanged. This, if it had been turned off to start an edit cycle, then it will still be off after the Special Process is run,

6 Page 3 thus allowing PPP050 to process normally. It if had been turned on for Periodic Maintenance, it will be left on, thus requiring a run of PPP020 to start the next edit cycle. Activity Generation Number: PPP120 and PPP130 both currently always set the Activity Generation Number to zero and update the SCR table. A successful run of PPP120 signals the end of an edit cycle, and thus it should reset the Activity Generation Number. PPP130 Periodic Maintenance does not normally run in the middle of an edit cycle, and its resetting of the Activity Generation Number prohibits, or at least makes difficult, the running of Periodic Maintenance during an edit cycle. A problem occurs when PPP130 runs for a Special Process during an edit cycle, a likely occurrence now that the Special Daily Process has been implemented. Leaving aside the issue of the Input Bypass Flag discussed above for PPP050, if an edit cycle were attempted after a Special Process had reset the Activity Generation Number, PPP080 would note the zero value of the Activity Generation Number, assume there was no Old Activity file, and would only process the new transactions. A rerun of PPP020 with an appropriate Activity Generation Number on the Run Specification card could allow the edit cycle to continue. However, a worse case can happen. If the Activity Generation Number is zero, PPP020 sets the Set Transaction Control Number to zero. This is the number used to keep set transactions together and is also the key needed when correcting errors for set transactions in earlier edit cycles. If two Special Processes were run, the first would set the Activity Generation Number to zero in PPP130, and the second would set the Set Transaction Control Number to zero in PPP020. There is no way via PPP020 to update this number as one can the Activity Generation Number. "Manual" intervention would then be required to get the edit cycle back in synch. PPP130 will be changed to only set the Activity Generation Number to zero during Periodic Maintenance. During any Special Process it will not be updated. EDB Generation Number: PPP120 and PPP130 both currently increment the EDB Generation Number and update the SCR table. The problem occurs when PPP130 runs for a Special Process during a Compute edit cycle, between the edit and the Compute, or between the Compute and the Check Write.

7 Page 4 During the Compute edit cycle, PPP360 compares the SCR EDB Generation Number and the PCR EDB Generation Number. If they are different, the re-edit flag is set on, and transaction edediting occurs. This is not a problem, and with online update should be done anyway. During the Compute, PPP390 and PPP410 compare the SCR EDB Generation Number and the PCR EDB Generation Number. If they are different, a message will be issued noting the change. In the Base system these messages are Warning level. The local effect depends on local changes to the message severity and local JCL Condition Codes. During the Check Write, PPP420 compares the SCR EDB Generation Number and the PCR Last EDB Generation Number. If they are different, PPP420 issues a message and performs a soft "abend" regardless of the message severity. Given online update, which does not update the SCR EDB Generation Number but does update the EDB, it is possible that the whole process of checking the EDB Generation Number is no longer needed. However, it is proposed to leave this process in place for any procedure that might rely on it. Since online EDB does not increment the EDB Generation Number and has not adversely affected the Compute, it is safe to presume that the incrementing can be removed from PPP130 during Special Processes without ill effect. PPP130 will be changed to only increment the EDB Generation Number during Periodic Maintenance. During any Special Process it will not be updated.

8 Page 5 Program Changes PPP020: Currently a non-blank value in the Periodic Indicators or Special Process Indicator fields of the System Control Record (UPAY630) causes section Set-Period-Indicators-4000 to be performed. Period Indicators can be updated, OR Period Indicators can be initialized, OR the Special Process Indicator can be updated. Only one of the events can occur in a single run of PPP020. If the Period Indicators are simply being initialized then the Bypass flag is turned off, i.e. SCR_INPUT_BYPASS is set to zero. Otherwise, the Bypass flag is turned on, i.e. SCR_INPUT_BYPASS is set to one. Thus, Period Indicators and a Special Process currently both turn the flag on. Changes: This code will be changed to not update the existing value of SCR_INPUT_BYPASS if a Special Process Indicator is being updated. It will retain whatever its value was from the last run of PPP020. This will leave it off if an edit cycle has been begun. It will leave it on if the last run of PPP020 was for Periodic maintenance. See Attachment A for sample code. Note: the sample code shown includes a fix to a formatting problem during the printing of the Activity Generation Number on report PPP0202. PPP130: PPP130 currently moves zeros to SCR_ACTVTY_GENNUM and increments SCR_EDB_GENNUM by +1 (or sets it to 1 if it is currently 99). Changes: The code will be changed to not reset SCR_ACTVTY_GENNUM to zero nor to increment SCR_EDB_GENNUM when a Special Process is being performed by PPP130. See Attachment B for sample code.

9 Page 6 Attachments Attachment A Proposed PPP020 changes. Attachment B Proposed PPP130 changes.