The document discusses new features in SAP HANA SPS09 for workload management. It introduces resource management capabilities for CPUs and memory to avoid overcommitments. It allows setting execution priority for SQL statements and provides emergency support modes when the system becomes unresponsive. The document also describes how to configure settings for workload management in HANA configuration files.

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SAP HANA SPS 09 - What’s New? SAP HANA Workload Management
SAP HANA Product Management November, 2014
(Delta from SPS 08 to SPS 09)

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Disclaimer
This presentation outlines our general product direction and should not be relied on in making a purchase decision. This presentation is not subject to your license agreement or any other agreement with SAP.
SAP has no obligation to pursue any course of business outlined in this presentation or to develop or release any functionality mentioned in this presentation. This presentation and SAP’s strategy and possible future developments are subject to change and may be changed by SAP at any time for any reason without notice.
This document is provided without a warranty of any kind, either express or implied, including but not limited to, the implied warranties of merchantability, fitness for a particular purpose, or non-infringement. SAP assumes no responsibility for errors or omissions in this document, except if such damages were caused by SAP intentionally or grossly negligent.

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HANA Workload Management – What’s New in SPS09?
Initial Scope (single-server)
•Avoid over-commitments of CPUs
•Avoid uncontrolled memory consumption
•Avoid db-restart, when HANA is not responsive at all
Extended Scope (single-server)
•Resource budgeting (CPU, Memory)
•Execution priority for SQL Statements

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Understanding HANA resource pooling (CPU)
HANA Indexserver
Session-Layer
Job Executor
“delegate”
Job Worker Threads
Minor other threads
DSO Activation …
simple statement
Complex statement (OLAP)
Simple statement (OLTP)
SQL Executor
Thread Pool
Thread Pool
complex statement
see also: Session “DMM112 – HANA scalability”
Major Thread-Pools
SqlExecutor
Handle incoming client requests
Execute simple (OLTP-like) statements
JobExecutor
Executes complex statements as parallelized jobs
Assigns Jobs to available threads
Other threads
In progress: Integration into JobExecutor

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Controlling HANA parallelism
indexserver.ini
•SqlExecutor: sql_executors = <min #threads that can be used> (default: # of available threads)
•SqlExecutor: max_sql_executors = <max #threads that can be used> (default: 0 <unlimited>)
•JobExecutor: max_concurrency = <max #threads that can be used> (default: # of available threads)
Important remarks
•JobExecutor settings do not solely affect OLAP workload, but also other HANA subsystems (e.g. memory garbage collection, savepoint writes)
•JobExecutor executes also DBMS operations (e.g. table updates, backups), which were delegated by the SqlExecutor
•JobExecutor settings are soft-limits, i.e. the JobExecutor can “loan” threads, if available, and falls back to the max# when done

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Controlling HANA memory consumption
global.ini
•global_allocation_limit =
•<max amount of physical memory that can be used by the db (default: 90% of physical memory)
•statement_memory_limit =
•<max amount of memory that can be used by a single statement> (default: 0 <unlimited>)
•statement_memory_limit_threshold =
•<apply the statement_memory_limit, if the current HANA memory consumption exceeds “statement_memory_limit_threshold %” of the global_allocation_limit> (default: 0%, i.e. statement_memory_limit is always applied)
Assign statement_memory_limit to a db-user
•ALTER USER <username> SET PARAMETER STATEMENT MEMORY LIMIT = <gb>

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Avoid db-restart, when HANA is not responsive
Emergency Support Mode
•Used by the administrator when the HANA db cannot be reached by SQL due to high load or blocking situations
•HANA studio provides a separate connection to the SAP start service (sapstartsrv)
•Collect information about connections, blocked transactions, and threads in the system
•Administrator can cancel individual connections and transactions, or even cancel all transactions
HANA
sapstartsrv
python
Indexserver
hdbcons

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Extended Scope: Resource budgeting (CPU, Memory)
Memory budgeting
global.ini
•global_allocation_limit =
•<max amount of physical memory that can be used by the db> (default: 90% of physical memory)
CPU budgeting
daemon.ini
•section [indexserver], [nameserver], [xsengine], [preprocessor], [compileserver]
•affinity = <core-ids of logical cores in the server>

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CPU budgeting and CPU binding – Details
Evaluate the topology of sockets and cores in the server (use sysfs to collect linux kernel information)
set affinity parameter in daemon.ini per HANA process
(e.g. [indexserver] -> affinity = c0-c7)
(re-)start HANA db
Remarks
•Affinity parameter assigns logical cores (threads) to HANA processes
•It allows to budget CPU resources to HANA
•It allows to bind HANA processes to cores on the same socket (NUMA)
•The affinity parameter is not set per default, i.e. all HANA processes use all logical cores
•Recommendation: Minimal number of logical cores per process = number of logical cores of one CPU
•Resource binding and NUMA-aware job execution are continuous development efforts

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Extended Scope: Execution priority for SQL statements
HANA-internal priority for mixed OLAP/OLTP workload
•HANA tries to detect “short-running” OLTP statements to give them a higher internal priority than long-running OLAP statements
•It allows HANA to execute OLTP statements “between” OLAP statements and thereby remain responsive in a mixed workload environment
User-level priority
•user-level priority for all statements in the current connection
•priority is between 0…9, default is 5
•Syntax:
•ALTER USER SYSTEM SET PARAMETER PRIORITY = '9'; -> set to highest priority
•SELECT PRIORITY FROM M_CONNECTIONS WHERE CONNECTION_ID = CURRENT_CONNECTION; -> get priority for current connection

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How to find SAP HANA documentation on this topic?
•In addition to this learning material, you can find SAP HANA platform documentation on SAP Help Portal knowledge center at http://help.sap.com/hana_platform.
•The knowledge centers are structured according to the product lifecycle: installation, security, administration, development:
SAP HANA Options
SAP HANA Advanced Data Processing
SAP HANA Dynamic Tiering
SAP HANA Enterprise Information Management
SAP HANA Predictive
SAP HANA Real-Time Replication
SAP HANA Smart Data Streaming
SAP HANA Spatial
•Documentation sets for SAP HANA options can be found at http://help.sap.com/hana_options:
SAP HANA Platform SPS
What’s New – Release Notes
Installation
Administration
Development
References
•

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Thank you
Contact information
Ruediger Karl
SAP HANA Product Management
Ron Silberstein
SAP HANA Product Management
AskSAPHANA@sap.com

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