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find if a parameter is dynamic in HANA

16th August 2021 / Leave a comment

We many times need to know whether a hana parameter is dynamic or a restart is required to make it effective. To check this goto below

open cdexe on the OS side, if you already configured this alias
otherwise go to the folder “cd /usr/sap/$SAPSYSTEMNAME/SYS/exe/hdb”
open the config folder by command “cd config”
open the Master ini files you need with the editor (do not adjust value in these files)
check the hint for the parameter you are looking for, there you will find configure online or offline

Example

Below files contains details about

Default values (not to be adjusted)
- /usr/sap/<sid>/HDB<inst>/exe/config
- /hana/shared/<sid>/HDB<inst>/exe/config
Valid for a specific service (e.g. indexserver) or component (e.g. multidb) on all hosts
- /usr/sap/<sid>/SYS/global/hdb/custom/config/<service_or_component>.ini
- /hana/shared/global/hdb/custom/config/<service_or_component>.ini
Valid for all services on all hosts
- /usr/sap/<sid>/SYS/global/hdb/custom/config/global.ini
- /hana/shared/<sid>/global/hdb/custom/config/global.ini
Valid for a specific service (e.g. indexserver) or component (e.g. multidb) on a specific host <host>
- /usr/sap/<sid>/HDB<inst>/<host>/<service_or_component>.ini
- /hana/shared/HDB<inst>/<host>/<service_or_component>.ini
Valid for all services on a specific host <host>
- /usr/sap/<sid>/HDB<inst>/<host>/global.ini
- /hana/shared/<sid>/HDB<inst>/<host>/global.ini

understanding sgen and pxa buffer

15th August 2021 / Leave a comment

There are n number of ABAP program in the system used for various functionalities/purposes, all these ABAP programs are stored in REPOSRC, for example below are the total number of programs in a S4HANA system.

Some are kind of must programs that needs to be compiled instantly when a user logs into the system or executes a transaction code. These compiled codes are placed in a table REPOLOAD, for example below are the total entries in a S4HANA system.

This table REPOLOAD is tightly integrated with PXA buffer, the PXA buffer is controlled by below parameters

abap/buffersize
abap/pxa_cache
abap/pxa_preload
abap/buffer_fragments

we can see the utilization of PXA or program buffer in ST02

Now,

When we start the AS ABAP Server, pxastat and pxanew in work directory is created, first wp-1 loads pxauserload, then pxanew, then pxastat, then will rename pxanew to pxastat, this deletes old pxastat, the pxa buffer is filled up to the percentage specified in abap/pxa_preload, once it is reached the preload is stopped. Once wp shutsdown it writes its pxa to pxanew.
if we run the ABAP program (or tcode) first time, it compiles and stores in REPOLOAD then stores in PXA buffer.
If we run another time the same ABAP program (or tcode), and the compiled program in REPOLOAD is changed then it will relook in REPOSRC compile it, place the compiled program in REPOLOAD, whenever a program is compiled it is placed in PXA buffer.

Now as I mentioned above parameters, there can be situations where the program might be dropped, then it will be again picked up from REPOLOAD into PXA, now if DB version is different we will get dump LOAD_PROGRAM_LOST.

Now if we activate a program from SE80 or SE38 then the activation timestamp is changed and PXA marks it as old, this information is sent to all abap servers asynchronously. Then all the reactivation process mentioned above is carried out.

With S4HANA we have a new job introduced with 1909, “SAP_SGEN_REGENERATE_LOADS”. The purpose of this is to minimize waiting times for users or developers by regenerating invalidated loads.

This job is periodic job which runs every hour, and run sgen for invalidated loads.

References

uninstall hana cockpit

31st May 2021 / Leave a comment

Note: The versions in my system is below

SAP HANA Database – version 2.00.047.00.1586595995
SAP HANA XS Advanced Runtime – version 1.0.127.426
SAP HANA Cockpit Stack – version 2.0.12.14.0

To Uninstall HANA cockpit please follow below.

GoTo /hana/shared/<Cockpit_SID>/hdblcm
choose option 10, then it will give you below options.
to uninstall all component choose all, or choose the required option and it will give you prompt for y/n, if everything looks good press y to proceed.
then uninstallation will start and once it completes it will give you below details, you should also check the log file mentioned at the last for any issues.

How to find SAP ABAP Schema Name?

12th June 2020 / Leave a comment

DB2

db2 "select tabschema from syscat.tables where tabname = 'SVERS'"

Oracle

SELECT username from dba_users where default_tablespace not in ('SYSTEM','SYSAUX');

Log utilization in DB2

1st June 2020 / Leave a comment

How to find log utilization in DB2?

db2 "select * from sysibmadm.log_utilization"

What do we mean by logs?

How to find all schema names in DB2?

1st June 2020 / Leave a comment

How to find all schema names in DB2?

```
db2 connect to <db_name>
```

db2 "select schemaname from syscat.schemata" OR

db2 "select distinct tabschema from syscat.tables"

List all Kernel Parameters

13th September 2019 / Leave a comment

In every Kernel Patches, either sap changes some parameter or adds/remove a parameter. If we are planning to add a new parameter we have to first verify if the parameter is supported by KERNEL or not. OR we can check by going through its particular note.

To do this follow below step to check if the parameter is included in the KERNEL or not

sappfpar all # will give list of all parameters

You can grep to check the parameter is supported in your KERNEL or not.

IDEALLY we should run sappfpar check after doing parameter changes, especially memory related parameters, but for planning for adding of new parameters we can use this step.

Important Links
* https://wiki.scn.sap.com/wiki/display/SI/SAP+Kernel:+Important+News