SAP HANA Architecture

How HANA Takes 30 to 40 Times the Memory of Other Databases

Executive Summary

  • HANA takes enormous levels of memory compared to competing databases.
  • HANA has continual timeout issues that are in part due to HANA’s problem managing memory.

Introduction to HANA’s Problems with Managing Memory

SAP’s database competitors like Oracle, IBM, and Microsoft, have internal groups that focus on memory optimization. Memory optimization (in databases) is how tables are moved into and out of memory. However, SAP tries to push more tables into memory that are necessary (but not as many tables as they state that they do, that is not “all the tables”). However, SAP does not have the optimization capabilities of the other database vendors.

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High Memory Consumption with HANA

HANA’s high memory consumption is explained in their SAP HANA Troubleshooting and Performance Analysis Guide, where they state the following.

“You observe that the amount of memory allocated by the SAP HANA database is higher than expected. The following alerts indicate issues with high memory usage.”

And…

“Issues with overall system performance can be caused by a number of very different root causes. Typical reasons for a slow system are resource shortages of CPU, memory, disk I/O and, for distributed systems, network performance.”

This is odd for SAP to observe shortages of resources. This is because HANA has the highest hardware specification of any other competing database. Also, the comparison is not even close. This is pointed out again by SAP regarding memory.

“If a detailed analysis of the SAP HANA memory consumption didn’t reveal any root cause of increased memory requirements it is possible that the available memory is not sufficient for the current utilization of the SAP HANA database.”

Conclusion

The same question arises, with so much memory usually part of the initial sizing, why is undersized HANA memory such an issue?