2543442 - DB6: Long running work processes on tables with LOB columns | SAP Knowledge Base Article

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2543442 - DB6: Long running work processes on tables with LOB columns

Symptom

When you execute some transactions, the system seems to come to a standstill, or the transactions run for a longer period than the normal.

In the meanwhile, the work process monitor (SM66/SM50) shows the processes are running on tables with LOB (Large Object) columns. RAWSTRING and STRING are ABAP dictionary datatypes that are represented by BLOB and CLOB columns respectively in the database.

Some of the most common tables are DYNPSOURCE, DYNPLOAD, REPOSRC, REPOLOAD, FPLAYOUTT, and FPCONTEXT.

sm66.PNG

The transaction will show up and the system will come back to normal after several minutes.

To confirm if the tables listed in SM66/SM50 contain LOB columns, use the following query:

SELECT table_name, column_name FROM dba_lobs WHERE owner = '<sapuser>';

Additionally, we can take a look into the STAD records of the long running transactions as shown in following figures:

stad1.PNG

Most of the time is spent on Database request time, and the average direct/sequential read time per row will be very high as shown in the STAD record above.

It may also show most of the time is spent in processing time as shown in the STAD record below. (This is due to how actions within a single dialog step are measured. The Load & Generate process will make DB requests which are not accounted for in the Database section of the STAD record and thus appear as increased processing time.)

stad2.PNG


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Environment

SAP Netweaver

Database: IBM DB2 for Linux, UNIX, and Windows

  • DB2 10.1 lower than fix pack FP5SAP
  • DB2 10.5 lower than fix pack FP6SAP

Product

SAP NetWeaver 7.0 ; SAP NetWeaver 7.1 ; SAP NetWeaver 7.2 ; SAP NetWeaver 7.3 ; SAP NetWeaver 7.4 ; SAP NetWeaver 7.5

Keywords

System hang, Performance , KBA , SV-PERF , Performance Messages , Problem

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