HANA update of table slowly, looking for improvments of update procedure

Hello,

I'm facing problem with very slow table updates. Currently I perform several 1000 updates on a table sequential. I would like to know some improvements for a better performance.

I will give a short introduce on what I'm doing exactly:

My starting situation is a table with sequences for different properties. Each value of the sequence represents one measured value for one day.

On this  I perform a sequential pattern mining using the SPADE implementation in R, getting as result a frequent sequence and the support of it. Let's say the result looks like following one:

Now I have a procedure which creates dynamical a table where each frequent sequence represents one column. The column name consist's of the property and the ID of the frequent sequence it represents (e.g "Temperature_1" stands for the freq. sequence "25:30"). Additional there are the columns sequence and property.

This table represents if a  frequent sequence occurs in a sequence or not. Therefore I fill them with 1 (occurs) or 0 (occurs not). E.g. as I mentioned column "Temperature_1" stands for the freq. sequence "25;30" this occurs in the sequence "22;25;30;24;20" so it will be "1" as it occurs also in "23;25;30;20;18" the second row in column "Temperature_1" will be also "1" but the third will be "0" as it's a totally other property.

Filling the table is also where I facing the performance problems.

In a first step I just insert the sequences and properties in the related columns.

To fill the table now with "0" or "1" for  occurrence or absence of a frequent sequence in a sequence I use the following algorithm:

-- iteration over all columns (frequent sequences)
FOR freqSequenceID IN 1..:maxFreqSequenceID DO  --get the propertie and the frequent sequence which the current column represents  SELECT "PROPERTY" INTO property FROM  FREQUENT_SEQUENCE_TBL WHERE "ID" = :freqSequenceID;  SELECT "SEQUENCE" INTO freqSequence FROM  FREQUENT_SEQUENCE_TBL WHERE "ID" = :freqSequenceID;  -- concatenate the name of current column  colName := CONCAT(:property,'_');  colName := CONCAT(:colName,freqSequenceID);  -- update all rows in the column with "0"  insertVar := CONCAT ('UPDATE OCCURENCE_TBL SET  "', :colName);  insertVar := CONCAT (insertVar, '" = 0');  EXECUTE IMMEDIATE (:insertVar);  -- update all rows where the current frequent sequence occurs in the sequence with one  --      UPDATE OCCURENCE_TBL SET  OCCURENCE_TBL.colName = 1 FROM OCCURENCE_TBL  --      INNER JOIN "SEQUENCE_TBL" ON OCCURENCE_TBL."SEQUENCE_ID" = SEQUENCE_TBL."SEQUENCE_ID" AND OCCURENCE_TBL."PROPERTY" = :property  --      WHERE LOCATE ( SEQUENCE_TBL."SEQUENCE", :freqSequence) >= 1 AND SEQUENCE_TBL."PROPERTY" = :property  insertVar := CONCAT ('UPDATE O SET  O."', :colName);  insertVar := CONCAT (insertVar, '" = 1 FROM OCCURENCE_TBL AS O INNER JOIN "SEQUENCE_TBL" AS S ON O."SEQUENCE_ID" = S."SEQUENCE_ID" AND O."PROPERTY" = ''');  insertVar := CONCAT (insertVar, :property);  insertVar := CONCAT (insertVar, '''WHERE LOCATE ( S."SEQUENCE", ''');  insertVar := CONCAT (insertVar, :freqSequence);  insertVar := CONCAT (insertVar,''') >= 1 AND S."PROPERTY" = ''');  insertVar := CONCAT (insertVar, :property);  insertVar := CONCAT (insertVar, '''');  EXECUTE IMMEDIATE (:insertVar);  
END FOR;

I think that the slow performance of it is because a update is sequential done for each column and not together at all in the end.

I tried already to collect all this update statement and execute them after the loop but it seems that with EXEC / EXECUTE IMMEDIATE only one statement is possible.

Has anyone an idea how to improve the update process of this table?

When it's possible it could be also a virtual table, it must be not persistent. In the next step it would be used for a classification with CART.

Thank you in advance

Matthias