FLEXPOOL (Dynamic Buffers)

The FLEXPOOL function dynamically adds or deletes data area or Index Area (DXX or IXX) flexible buffers to the system.
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The FLEXPOOL function dynamically adds or deletes data area or Index Area (DXX or IXX) flexible buffers to the system. The flexible part is that, with the FLEXPOOL function, these buffers can be removed from the system (normal buffers cannot). Therefore, for example, you can use the MUF startup option FLEXPOOL to add 500 data buffers and later reduce that number with the DBUTLTY FLEXPOOL function. You can also use the DBUTLTY FLEXPOOL function to add flexible pool buffers up to the maximum combined total for the MUF startup option and the DBUTLTY function (and the DATAPOOL or SYSPOOL buffers) of 99999 for each class. The alternate buffer pools defined with BUFFER_POOL_DEF also count in the maximum per class (IXX, DXX, data).
The FLEXPOOL function communicates with one MUF. Be aware of the following:
  • Ensure that DBUTLTY is communicating with the desired MUF by executing DBUTLTY with the same System Identifier module (DBSIDPR) that is being used by the MUF
  • Ensure proper load library concatenation by keeping the System Identifier modules (DBSIDPR) in separate load libraries.
If the z/OS Cross-System Coupling Facility (XCF) is being used, help ensure that the TOGROUP DBSIDPR parameter is correctly defined.
When using a console command, these steps are unnecessary.
The following topics are discussed on this page:
 
 
When to Use FLEXPOOL
Use FLEXPOOL to add or delete flexible buffers.
To see the current flexible buffer counts, use a FLEXPOOL add or delete statement for the desired buffer class with 0 specified. The function generates a message, on the console or on the DBUTLTY report, indicating the status of the request and the number of buffers added or deleted, remaining, and totals.
 The total buffers by type are those buffers for general use. They do not include any special data buffers added for sequential processing.
How to Use the Console Command (FLEXPOOL)
The MUF must be active when you execute this command.
Use the following in your command to initiate this function from the system console. Consult your site operating system documentation for additional syntax information.
►►─ FLEXPOOL ─┬─ ADD ────┬─┬─ ,DATA ──┬─
,number
─────────────────────────────►◄ └─ DELETE ─┘ ├─ ,DATA2 ─┤ ├─ ,DXX ───┤ └─ ,IXX ───┘
 
Command
 
  •  
    FLEXPOOL
    Invokes the function for dynamic buffer maintenance.
 
Required Keywords
 
  •  
    ADD
    Specifies to add buffers.
  •  
    DELETE
    Specifies to delete buffers.
  •  
    ,DATA
    Indicates data area primary buffers.
  •  
    ,DATA2
    Indicates data area secondary buffers, larger buffers than the primary buffers.
  •  
    ,DXX
    Indicates low-level Index Area buffers.
  •  
    ,IXX
    Indicates high-level Index Area buffers.
  •  
     
    ,number
     
    Specify the number of buffers of the type indicated that are to be added or deleted.
    •  
      Valid Entries:
      0 to 9999
    •  
      Default Value:
      (No default)
How to Use the DBUTLTY Command (FLEXPOOL)
The MUF must be active when you execute this command. To use this function, execute 
Datacom/DB
 Utility (DBUTLTY) using the command:
►►─ FLEXPOOL OPTION= ─┬─ ADD ────┬─ ,AREA= ─┬─ DATA ──┬─ ,NUMBER=
nnn
─────────►◄ └─ DELETE ─┘ ├─ DATA2 ─┤ ├─ DXX ───┤ └─ IXX ───┘
 
Command
 
  •  
    FLEXPOOL
    Invokes the function for dynamic buffer maintenance.
 
Required Keywords
 
  •  
    OPTION=
    Specifies the type of activity to be performed.
    •  
      Valid Entries:
      ADD or DELETE
    •  
      Default Value:
      (No default)
  •  
    ,AREA=
    Specifies the type of buffer to be added or deleted.
    •  
      DATA
      Indicates data area primary buffers.
    •  
      DATA2
      Indicates data area secondary buffers, larger buffers than the primary buffers.
    •  
      DXX
      Indicates low-level Index Area buffers.
    •  
      IXX
      Indicates high-level Index Area buffers.
    •  
      Valid Entries:
      DATA, DATA2, DXX, or IXX
    •  
      Default Value:
      (No default)
  •  
    ,NUMBER=
    nnn
     
    Specify the number of buffers of the type indicated that are to be added or deleted. If the amount of memory does not allow the total number requested to be added, as many as possible are added. If the number requested to be deleted is more than exists for the type of buffer, as many as exist are deleted.
    •  
      Valid Entries:
      0 to 9999
    •  
      Default Value:
      (No default)
Example JCL (FLEXPOOL)
 Use the following as a guide to prepare your JCL. The JCL statements are for example only. Lowercase letters in a statement indicate a value you must supply. Code all statements to your site and installation standards.
//jobname
See the previous note and
.
// EXEC PGM=DBUTLTY,REGION=2M //STEPLIB
See the previous note and
.
//SYSIN DD * Command input FLEXPOOL OPTION=ADD,AREA=DATA,NUMBER=20 /*
Sample Report
Following is a sample report page. For an example report header, see Sample Report Headers.
 
CONTROL CARD(S) .........1.........2.........3.........4.........5.........6.........7.........8 FLEXPOOL OPTION=ADD,AREA=DATA,NUMBER=20 FUNCTION=FLEXPOOL OPTION=ADD AREA=DATA NUMBER=20
This page of the report shows the following:
  • The command exactly as entered.
  • An analysis of keywords encountered and expected. Any errors found are flagged with a note in the left margin.
  • Any messages related to syntax processing.
DB00606I - FLEXPOOL ADD DATA 00020, NOW TOTAL 00220 FLEXPOOL 00020
This page of the report shows the following
  •  
    FLEXPOOL ADD
    Indicates the ADD or DELETE function.
  •  
    DATA
    Indicates the buffer class (data, IXX, or DXX).
  •  
    00020
    Indicates how many buffers were processed during this request. That is, if the request was to add 1000 but there is only enough memory for 700, this value is 700. Also, if FLEXPOOL had 700 and a delete request was made for 9999, this value is 700.
  •  
    TOTAL 00220
    Indicates the total number of buffers in this class (includes the MUF startup options, DATAPOOL and SYSPOOL, plus any FLEXPOOL buffers).
  •  
    FLEXPOOL 00020