1872652 - SAP HANA Smart Data Access: Statistics for Virtual Tables

Symptom

This is a SAP note with specific information about SAP HANA smart data access.

Other Terms

data federation, SAP HANA appliance, SAP HANA platform,

Reason and Prerequisites

You are using the SAP HANA platform as of SPS06. With SAP HANA SPS06 SAP HANA smart data access has been shipped for the first time.

Solution

The current functionality of SAP HANA smart data access supports creation and deletion of statistics on virtual tables only. You can create and drop statistics using the following comands:

• CREATE STATISTICS

           You can create statistics using the following command but you need to specify the column list:
           [NOTE: Creating statistics on a virtual table can be an expensive operation, especially when it has a large number of rows and columns.]
           CREATE STATISTICS ON <table name>  (< column_name> {, <column_name>},..)] [TYPE HISTOGRAM]
           The keywords "TYPE HISTOGRAM" is optional but type of histogram objects.
           Examples:
           To create histogram on all columns of virtual table "ASE_TAB1" that has five columns "a1", "a2", "a3", "a4", and "a5", you will have to issue the following command
            CREATE STATISTICS ON "ASE_TAB1" ("a1", "a2", "a3"," a4", "a5");
           To create histogram on columns "a1" and "a5" of "ASE_TAB1", you will have to provide the column names to the CREATE STATISTICS command as shown below:
           CREATE STATISTICS ON ASE_TAB1(a1, a5) TYPE HISTOGRAM

• DROP STATISTICS

           You can drop statistics using the following command:
           DROP STATISTICS ON <virtual_table_name>   [(<column_name> {,  <column_name>},..)]
           Examples:
           To drop all histogram statistics on the virtual table "ASE_TAB1", you will use the following command:
           DROP STATISTICS ON "ASE_TAB1";
           To drop statistics on column "a5" of the virtual table "ASE_TAB1", you need to use the following command:
           DROP STATISTICS ON "ASE_TAB1"("a5");

For more information about the following SQL comands:

• CREATE STATISTICS

• DROP STATISTICS

• REFRESH STATISTIS

see the SAP HANA SQL Reference on SAP Help Portal
http://help.sap.com/hana/SAP_HANA_SQL_Reference_en.pdf

Header Data

Released On	02.07.2013 14:42:37
Release Status	Released for Customer
Component	HAN-DB SAP HANA Database
Priority	Correction with high priority
Category	Advance development