Technical Articles
Collected information about memory in context of SAP HANA
last updated: 2023-03-11
Introduction
SAP HANA is an in-memory database architecture. This architecture is the heart of the concept. Huge knowledge available about SAP HANA memory topic, but the knowledge is fragmented (Help Portal, Blog post, SAP KBA, SAP Note, other). In order to simply and make content consumption easier I have created a centralized page, a single source of the available information regarding SAP HANA memory.
Table of Content
- Where to find documentations in SAP Help Portal?
- Which is the master SAP Knowledge Base Article of the SAP HANA memory?
- Concept of the SAP HANA memory structure
- Which memory measurement values needs to be understand?
- What does resident means?
- How to limit SAP HANA memory consumption?
- What is the general way to monitoring the SAP HANA memory usage?
- What are the available tools for monitoring the SAP HANA memory usage?
- Which SAP HANA Alert IDs belongs to the topic?
- What is the recommended way of troubleshooting the SAP HANA memory usage?
- What else is recommended to check in case of memory issue?
- Which other documentation is important regarding SAP HANA memory?
- What blog posts can be helpful?
- Other articles in this series
- Other articles in connected series
- Useful bookmark
IMPORTANT !
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Where to find documentations in SAP Help Portal?
- SAP HANA Developer Guide – SAP HANA In-Memory Database
- SAP HANA Administration Guide for SAP HANA Platform – Memory Usage in the SAP HANA Database
- SAP HANA Troubleshooting and Performance Analysis Guide – Memory Problems
Which is the master SAP Knowledge Base Article of the SAP HANA memory?
- 1999997 – FAQ: SAP HANA Memory
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Concept of the SAP HANA memory structure
This is essential to understand the memory concept of the SAP HANA database system. The most used illustration explains how the memory structure looks like and which important areas are exists.
Image source: SAP Knowledge Base Article – 1999997 – FAQ: SAP HANA Memory
❗Rule of thumb: the recommendation from SAP is the tables data should not use more than 50 % of the available memory.
- 1999997 – FAQ: SAP HANA Memory
➡️ 45. What is a good table memory share?
➡️ 10. How can I judge if the available memory is sufficient for the current system and a projected future growth?
Which memory measurement values needs to be understand?
Below graph shows different memory measurement values on a time scale.
Image source: HA200 – SAP HANA 2.0 SPS05 – Installation and Administration
Basic understanding and high level quick overview, about SAP HANA memory management explained in the SAP HANA Academy content.
Overview of these memory usage indicators can be checked in SAP HANA Studio.
SYSTEMDB:
HXE (Tenant DB):
❗Note: While we are checking the values, only the ‘Database Resident’ numbers are different. This number belongs to the actual database while other numbers are belongs to the overall system.
What does resident means?
SAP HANA database is greedy. It means the database reserves its memory even if it is not used. SAP HANA does not care if some amount memory actually not used by the database. It assumes if memory assigned (GAL) to the database and it was used before, it will be used in the “near” future, so the database does not release the memory.
The related SAP HANA documentations:
- 2081473 – SAP HANA Resident Memory: High Memory Usage
- 3134933 – HANA database Resident memory is different from OS command “free -h”
- 2743981 – Resident Memory and Used Memory for MDC system in HANA Studio Overview
How to limit SAP HANA memory consumption?
- 3202692 – How to set Memory Limit for SQL Statements
- 2383578 – How to set HANA memory limit for a single user
- 2926166 – How to limit the overall SAP HANA memory allocation
- 2175606 – HANA: How to set allocation limit for tenant databases
- 2924720 – Is it possible to Limit maximum memory allocation of SYSTEMDB?
What is the general way to monitoring the SAP HANA memory usage?
- 3058134 – Monitoring SAP HANA Memory usage statistics
What are the available tools for monitoring the SAP HANA memory usage?
The general way to do the monitoring is to use SQL commands. The actual memory information can be reviewed with the following SQL Statement: “HANA_Memory_Overview”.
- 1969700 – SQL Statement Collection for SAP HANA
- 3330262 – SQL Statement Collection: “HANA_Memory_Overview” report for SAP HANA
The action can be done in a graphical way also.
- SAP HANA Administration with SAP HANA Studio – Memory Indicators in the SAP HANA Studio
- SAP HANA Administration with SAP HANA Cockpit – Memory Analysis
SAP HANA Academy video explains the memory monitoring process via SAP HANA Cockpit.
Which SAP HANA Alert IDs belongs to the topic?
- 1840954 – Alerts related to HANA memory consumption
What is the recommended way of troubleshooting the SAP HANA memory usage?
- 3011480 – How-To : Troubleshooting SAP HANA Memory Consumption
❗Note: The following documentation describes the most typical and common scenarios users encounter during memory pressure situations. Memory related SAP HANA Alert IDs are also listed here.
What else is recommended to check in case of memory issue?
In general the parameters needs to be checked, also improper parameter setup cause memory issue in many case.
- 2600030 – Parameter Recommendations in SAP HANA Environments
Which other documentation is important regarding SAP HANA memory?
- 2222250 – FAQ: SAP HANA Workload Management
- 2332170 – How-To: Analyzing SAP HANA composite OOM dump
- 1984422 – How-To: Analyzing SAP HANA Out-of-memory (OOM) Dumps
- 2399990 – How-To: Analyzing ABAP Short Dumps in SAP HANA Environments
- 1998599 – How-To: Analyzing high SAP HANA Memory Consumption due to Translation Tables
- 2222718 – Troubleshooting HANA High Memory Consumption – Guided Answers
What blog posts can be helpful?
- SAP HANA – Detailed Memory Analysis Walkthrough
- How to identify the SQL statement text from compositelimit oom trace
- Further explained on Linux Free Memory, Virtual Memory, Resident Memory vs HANA used Memory and Pool Memory
✍️ Collected information regarding partitioning in SAP HANA (with examples)
✍️ Collected information regarding High Availability and Disaster Recovery in SAP HANA
Other articles in connected series
✍️ Where can I find knowledge and information belongs to SAP HANA?
✍️ Where can I find information about the available tools for SAP HANA (all types of use)?
🔖 2872774 – Bookmark of Frequently Asked Questions for SAP HANA
🔖 3311408 – Bookmark of SQL Statement Collection reports for SAP HANA
Do you have further questions?
Q&A link for SAP HANA: https://answers.sap.com/tags/73554900100700000996
Contribution
If you find any missing information belongs to the topic, please let me know. I am happy to add the new content. My intention is to maintain the content continuously to keep the info up-to-date.
Release Information
| Release Date | Description |
|---|---|
| 2023.02.15 | First/initial Release of the SAP Blog Post documentation (Technical Article). |
| 2023.03.11 | Section added: Table of Content |
Great job Laszlo,
All related info together including referenced notes and HANA Academy videos .I'm going to book mark this blog for sure!
Thanks !
Hi Amin,
Thank you for the feedback. My intention is to maintain the content continuously to keep the info up-to-date. You can count on updates from time to time.
Regards,
Laszlo
Great article Laszlo Thoma ! Thanks for compiling and keeping the article current.