Configuration of an offset extraction in terms of time or value

The functions described in this chapter are supported only by the two process extractors Process Extractor SAP-2-PPM and Process Extractor JDBC-2-PPM and only when using a data source configuration.

For the time-based extraction, you can specify a time value in the data source configuration. The value is subtracted from the current execution time as the end time when executing the corresponding command line program without end time parameters (-enddate or -endtime). Data extraction will end earlier by the specified value (in seconds).

Without specifying a time offset value, data records that have been created but not written explicitly to the database to be extracted might not be extracted in any of two subsequent extraction operations due to their offset time stamp (see Continuous automated extraction). This can be prevented by specifying an offset value.

Example (SAP data source)

<?xml version="1.0" encoding="ISO-8859-1"?>

<!DOCTYPE datasource SYSTEM "datasource.dtd">

<datasource name="SAP" type="MYSAP" lastreaddate="19700101"

lastreadtime="000000" readoffset="86400">

<description name="default_description" language="en"/>

<description name="default_description" language="de">
SAP
</description>

...

</datasource>

The readoffset XML attribute indicates an offset value of 86400 seconds. When calling the command line program with

runsap2ppm -datasource SAP.xml

the extraction operation ends one day (86400 seconds) before the current execution time. If the program execution time is 11.08.08 9:48:05, the extraction operation ends on 10.08.08 at 9:48:05.

...

I: 11.08.08 09:48:06: [XML] Reading data with start date/time 19700101/000000 and end date/time 20080810/094805...

...

The offset value of the last extraction time is written to the data source file as the start time for the next data extraction.

For the conditional extraction using an integer criterion (logical operator valueconstraint, see Extraction using conditions), you can similarly specify an offset value that is subtracted from the start value (lastreadvalue from the data source file) when running the program. If the result of your data is a negative value for the integer criterion, this value is handled like a positive value.

An offset value specified in the data source configuration is included in data extraction only if the end time or the lower limit of the integer criterion is not explicitly specified. 

Tip

You can easily configure offset values in PPM Customizing Toolkit in the Client module group under Data source management. Enter the value as additional information for the last extraction time or the last value extracted in the components of the relevant data source. 

Specify a time zone

If you have not specified the end time in the command line (-enddate or -endtime arguments) the current time of the local computer is used as end time by default. This end time is used for the creationtimestamp, date_creationtimestamp, or char_creationtimestamp operators to restrict the data volume to be extracted. If the data field referenced in the operators contains time stamps assigned to a different time zone, you can specify this time zone in the sourcefieldtimezone XML attribute (e.g. Australia/Canberra). In the subsequent data extraction, the local computer time is converted to the time zone specified, and after successful extraction the time is saved as last time of extraction (lastreaddate and lastreadtime XML attributes) in the data source.

If no valid time zone or the attribute itself is not specified in the sourcefieldtimezone XML attribute, a time zone conversion of the end time will not be carried out. With CTK, the time zone can be easily selected using the interface.

Time zone examples

Africa/Dakar, Africa/Johannesburg, Australia/Sydney, America/Denver, America/Los_Angeles, America/Mexico_City, Canada/Central, Europe/Berlin, Europe/London, Mexico/General, US/Central, US/Hawaii