How to detect when the size of a BLOB column read exceeds a threshold (PEGA0039 alert)

This alert is generated when a database query retrieves a BLOB (pzPVStream property value) that is larger (in bytes) than the threshold value. The alert provides a warning that memory performance of your system may be hurt when Process Commander expands the BLOB onto a clipboard page.

In contrast to this alert, the similar PEGA0004 alert indicates the size of the entire result set of a query, that may or may not include a BLOB in the individual rows.

Alert log message

The alert identifies the pzInsKey that was read, and the size in bytes of the BLOB:

Read blob from database with compressed size 2058486 expanded size 4125916. pzInsKey: RULE-FILE-BINARY WEBWB OPENAUTHORING!CAB #20100304T152007.144 GMT

Modifying the alert settings

You can modify the default alert settings as follows:

1. Add or edit the following prconfig Dynamic System Settings:
   

   Dynamic System Setting: prconfig/alerts/database/blobsizeread/enabled/default
   The prconfig/alerts/database/blobsizeread/enabled/default setting enables the PEGA0039 alert log entry to be written to the ALERT log if a database query retrieves a BLOB column larger than the threshold value. If this setting is disabled, then no PEGA0039 alerts will be created. The following values are valid for this Dynamic System Setting:
   Value	Description
   true	PEGA0039 alert enabled. (Default)
   false	PEGA0039 alert disabled.

   Dynamic System Setting: prconfig/alerts/database/blobsizeread/threshold/default

   The prconfig/alerts/database/blobsizeread/threshold/default setting defines the threshold BLOB size for the PEGA0039 alert. The following describes the valid values for this Dynamic System Setting:

   Value Description

   Integer. Sets the threshold value, in Megabytes, for the PEGA0039 alert. If a database query retrieves a BLOB column larger than the this value, a PEGA0039 alert is written to the ALERT log. The default value for this setting is 3.

   Change this setting with care. Prconfig Dynamic System Settings can have broad impact on the operation of your system. See How to create or update a prconfig setting.

   
   

2. Stop and restart the server.

 

Next steps

Examine the record being read (identified by the pzInsKey value and determine if the entire BLOB is needed. Usually, you can break the data into additional logical segments (as dictated by your application). This alert is often related to PEGA0004 and PEGA0025 alerts.

Related PDN articles

Consult these Pega Developer Network articles:

• PRKB-25335 Understanding the PEGA0004 Alert
• PRKB-25362 Understanding the PEGA0025 Alert
• PRKB-23116 How to detect and remedy the performance impact of Obj-List methods and List View reportswas PRKB-19879

	alert log, prconfig.xml file, storage stream, schema
	Understanding alerts How to detect when size of BLOB column written to the PegaRULES database exceeded a threshold (PEGA0040 alert) How to detect when total BLOB column sizes in an a single HTTP interaction exceed a threshold (PEGA0004 alert)

SysAdmin category