HANA backtrace 45/2011

Ok, it’s been more than the planned week since my last post in this series (HANA backtrace 44/2011) but these are very busy times lately for a primary support guy like I am.

I write this post from our US Headquarter offices in Newtown Square near Philadelphia and that’s because I’ve been asked to deliver several internal HANA training workshops for our AGS colleagues over here. Thus, I booked the flight, packed my bag and flew over here.
And there we are – right in the middle of a quite packed training week, covering topics like performance analysis, modelling, data services and backup/recovery (and lots more).
And just as we’re in full flight, we see HANA SPS 03 being released to customers.

With this, many new features, usage types and bug fixes have been made available to HANA users.
Make sure not to miss out on the updated SAP HANA documentation.

For the HANA database, this is revision 20 and the changes that have been made in this revision are documented in SAP note #1648901 SAP HANA database Revision 20.

The actual SPS 03 release notes can be found as an attachment to SAP note #1642937 SAP HANA Appliance Software SPS 03 Release Note.

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With SPS 03 a new software installation tool (Software Update Manager, SUM)  had been released for HANA systems.
See SAP note #1545815 SAP Release Note for SUM for SAP HANA 1.0 to get the details.
The nice thing about this is, you can easily manage the upgrades of HANA related software parts all at once.

Also very important to know is that with SPS 3 now log backups are supported with the HANA database.
Note #1645183 Changing log mode for SAP HANA DB after SPS2 to SPS3 upgrade talks about the changes in log mode that have to be implemented for this to get activated.

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With SPS 03 a new way to access data from a HANA system had been released to customers: the web-based SAP HANA Information Composer. Find details in the following two notes

#1627904 SAP HANA Information Composer: Central Note
#1633168 SAP HANA Information Composer: SP3 Release Note

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Just a small code fix for a data type change for function module TREX_EXT_SHOW_INDEX is delivered by sap note
#1652229 SAP HANA: error code -10404 with TREX_EXT_SHOW_INDEX

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As far as I know, the pricing in HANA is based on the amount of data used with HANA, so the importance of a proper sizing is self-explanatory. SAP Note
#1637145 SAP BW on HANA: Sizing SAP In-Memory Database
contains the information about how to size a HANA system if you want to migrate your existing SAP BW system to it.

Which reminds me: BW on HANA has also been made available by the release of HANA SPS 03 and SAP BW SP5.

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Also related to the migration of ABAP systems to run on HANA is note
#1634681 DB Migration: Report for finding large Row Store Tables
which basically makes sure that you don’t overlook very large tables that should be put to the row store.
Why can this be an issue?
That’s because unlike column store tables, row store tables are always fully loaded into memory on HANA instance startup. So if too much data is put into such tables, it might be that the instance won’t come up anymore, since the automatic loading of these tables fails.

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As with all NetWeaver main databases, which is a use case for HANA as well (e.g. BW on HANA) there is the usage of a database sequence called DDLOG_SEQ. Unfortunately, older HANA revisions didn’t support persisted sequences, so after a restart of the HANA instance, the instance would actually be reset to its initial value.
To prevent this, see SAP note #1648526 Incorrect values for DDLOG sequence.

Talking about HANA usage with NetWeaver systems, the database interface library (DBSL) is a core piece of technology – so make sure to have SAP note #1600066 – verfügbare Patches der DBSL für NewDB on your radar to keep track of the latest fixes to it.

And, while you’re already at it, just also check SAP note #1597627 – HANA connection about the secondary database connection with HANA.

In case you should check your SM21 system log from time to time and find error messages that indicate ‘database system is not supported’ since you’re running on HANA, then SAP note #1650209 SM21 Meldung: “Datenbank System wird nicht unterstützt” is for you.

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I was quite happy to learn that there are also helper tools for HANA created for mere support folks like me when I found SAP note #1647717 Für den SAP-Support: Prüfprogramm für Tabellen.
This note contains a little check program that looks out for tables stored in HANAs column store that might require a MERGE of the delta indexes (in case the automatic MERGE had been turned off).

Nicely also SAP note #1652078 SAP HANA database: Hardware check is also kinda support related.
Since HANA revision 18, a little python script is delivered with HANA and executed during installation time.
It basically checks and reports whether your hardware is actually supported for HANA and it looks like my test instance definitively is not… 🙁

logon as root...
vml3012:/usr/sap/HAN/SYS/exe/hdb/python_support # python HanaHwCheck.py
performing Hardware check......
could not get Hardware Information: 'CPU Flags'
assuming largest storage device  /sapmnt/vml3012/a as data device....
assuming 2nd largest storage device  /dev/shm as log device....
System Manufacturer            VMware, Inc.              not supported
System Product Name            VMware Virtual Platform   not supported
could not get Hardware Information: 'CPU Model'
Hardware check failed!!

As a final support related sap note, there is #1641210  SAP HANA datebase: Checking for suspected problems.
So, in case there is any kind of issue, it’s sure a good idea to go through the steps mentioned in this one to avoid the common “traps”.

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For the SLT users, the following SAP notes are surely a must read/implement:

#1605140 SAP HANA 1.0: Central Note – SAP LT Replication Server
#1647648 HANA LTR – corrections for DMIS 2010 SP4 111031 (stop repl)
#1625755 SAP LT Replicator – individual table settings
#1649910 Applying SLT (DMIS_2010 SP05)with SAP HANA SPS03
#1650191 Syntax change in NEW-DB 111108

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In case you’re running HANA on IBM storage you should give SAP note #1650046 GPFS maintenance after SAP HANA node has failed a read to learn about the required checks to be performed when a cluster node failover happened.

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Other releases

As I barely had time to go through the notes while preparing my training sessions, I didn’t make it to the blogs on HANA this week. However, I’ve seen that there had been several HANA related posting, especially in connection to the recent SAP TechED, so give yourself a treat and check “SAP Blogs on In-Memory Business Data Management”  to catch up with them

So, that’s it for this week. I expect more to come for HANA, so see you next week.

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