Applies to:
SAP BW 3.5 , SAP BW 7.0.
Summary
This wiki helps in exlporing the various table types in order to understand which is the most optimal way to use and where..
Author(s): Vikram Srivastava
Company: Infosys Technologies Ltd.
Created on: 29-12-2009
Author(s) Bio
Vikram Srivastava is working as Technology Analyst with Infosys Technologies Limited. He has got rich experience on various BW Implementation/Support Projects in both SAP BW 3.5 and SAP BW 7.0.
READ TABLE WITH KEY
|| Table Types || Processing Manner || Time Taken ||
Sorted Table |
Complete table in scanned to read the data. If the key is a part of the table key then also full table scan is done , but to find out the first row BINARY SERACH is used. |
More the number of records,more is the time taken. |
Hashed Table |
Complete table in scanned to read the data. If the key contains all the table keys then HASHED PROCESS is used. |
More the number of records,more is the time taken. |
Standard Table |
Complete table in scanned to read the data row by row. |
More the number of records,more is the time taken. |
READ TABLE WITH TABLE KEY
|| Table Types || Processing Manner || Time Taken ||
Sorted Table |
A BINARY scan is used to read the record. |
It is proportional to log ( number of entries) |
Hashed Table |
HASHED process is used to read the record. |
It has a constant access time. |
Standard Table |
Complete table in scanned to read the data row by row. |
More the number of records,more is the time taken. |
READ TABLE INDEX
|| Table Types || Processing Manner || Time Taken ||
Sorted Table |
Complete scan is not required. |
Constant Time |
Hashed Table |
It is not possible. |
|
Standard Table |
Complete scan is not required. |
Constant Time |
LOOP AT TABLE WHERE
|| Table Types || Processing Manner || Time Taken ||
Sorted Table |
If the WHERE clause contains the first part of the key with a query on = , a binary search is used uo to a entry point. |
Log(number of table entries) + number of hits in first case ,else more the number of records,more is the time taken. |
Hashed Table |
Complete table in scanned. |
More the number of records,more is the time taken. |
Standard Table |
Complete table in scanned to read the data row by row. |
More the number of records,more is the time taken. |