When issuing D STOR it may happen that the number in field "Overflows" is greater than zero, but Slot 12 shows no Failed Requests. How can this happen?

Products

• TPX - Session Management

Issue/Introduction

D STOR gives information about the storage usage below the 16MB-line. You are getting information about failed Slot Requests and Overflows. These Overflows are normally caused by a failed request for a Slot12-Storage (normally of size 10k).

 

 

Resolution

When issuing D STOR it may happen that the number in field "Overflows" is greater than zero, but Slot 12 shows no Failed Requests. like shown below in this example of the Output of a D STOR command:

TPX  ******************* TPX Operator    ************************* XXX0217

                         Storage Statistics (Below 16M line)

Open ACBs:   1852   Total ACBs:  03869  Terminals: 1711 Applications: 3075
DSA  Bytes: 04771840 Current Use: 013%  High Use:  019% Free Areas:   0005
Slot Bytes: 01114112 Current Use: 000%  High Use:  006% Overflows:   00439

 Slot   Size  * Count  =  Bytes     Curr.Use   Max.Use   Failed    Requests
  01    00008   3072      24576       000 %     000 %    0         4078    
  02    00016   1536      24576       000 %     000 %    0         20873186
  03    00032   768       24576       000 %     000 %    0         601440  
  04    00064   384       24576       008 %     010 %    0         490478  
  05    00128   192       24576       006 %     031 %    0         2292120  
  06    00256   336       86016       000 %     003 %    0         1943064 
  07    00512   72        36864       001 %     008 %    0         387088  
  08    01024   48        49152       000 %     012 %    0         184934  
  09    02048   80        163840      000 %     018 %    0         3797037 
  10    04096   72        294912      000 %     008 %    0         774380  
  11    08192   24        196608      000 %     012 %    0         153061  
  12    10240   16        163840      000 %     006 %    0         62227  
******************************** BOTTOM OF DATA ***************************

You can see that there are Overflows but no failed request for Slot 12.

The reason for these number of overflows is a GETSTOR request from TPX with LOC=BELOW,SLOT=YES and BYTES>10240. In several functions TPX issues such a GETSTOR LOC=BELOW,SLOT=YES where the number of bytes requested is calculated for the current situation. If the number of bytes is larger than the size of Slot 12 TPX will not modify the GETSTOR into SLOT=NO. It will leave this as SLOT=YES resulting in an increase of the overflow counter.

There is nothing to worry about this behavior. The storage is taken from DSA. If the values "High Use:" for the DSA- and the Slot-Storage are below the given thresholds then TPX runs normal. We suggest to observe the storage on a regular basis by using the concept of OPENGATE-User.