Please help to explain me in detail about SAP Sybase ASE architecture

[DilipVoora]

Please help to explain me the concepts that are listed below in a detailed manner,

a) Architecture of SAP Sybase ASE

b)About internal threads and their functionalities

c)Shared memory
d)Also how does ASE executes an SQL or update statement?

NOTE: I am a beginner and looking forward for your valuable response.

[DilipVoora · Accepted solution]

Hi Kiran/Nicolaas,

I will be very much great if you guys elucidate the concepts in a Lehman terminology. As,I am in learning stage, trying to understand the basic concepts first in an easy way. I found the links are a bit higher and profound. Please help me over this.

Regards,

Dilip Voora.

[former_member187136 · Accepted solution]

Hi Dilip,

May be you can refer the below link: http://help.sap.com/ase1601?current=ase16

These are the classifications may be you can understand:

• What’s New
• Release Notes
• Installation and Upgrade Information
• Configuration Information
• System Administration and Maintenance Information
• Security Information
• Performance and Tuning
• Reference
• Glossary
• SAP Adaptive Server Enterise Options

Regards

Kiran K Adharapuram

[former_member207908 · Accepted solution]

Hi Dilip,

Any RDBMS contains three important components

1. Storage..think about disk or your database or files (A file can be an image or video or a pdf etc.,)

2. Memory.. Allocated RAM to your RDBMS..think about fast response times. more memory = faster response times.

Note: Disks IOs are slower when compared to Memory IOs

3. Some processes running in the background...These are mandatory for your server to run and are called as ASE internal threads (known as Background processes in Oracle)

Others include..executable files like ASE RUN server file, Errorlog file, Interface file and Configuration file.

Technically..

1. Your storage in Sybase is Databases;System databases (master, model, tempdb, sybsystemprocs, sybmgmtdb and saptools and saptempdb for SAP Applications) and User databases

2. Shared Memory is the technical term we use in ASE to indicate your memory which again is divided into 3 major components

• Procedure Cache: This is the place where compiled programs (called stored procedures for faster response times) are stored along with SQL statements abstract plans (in statement cache) to reduce the query optimization time
• Data cache: This is the place where the user (client process) gets his requested data actually from (Logical IO). If the requested data is not found in data cache, ASE fetches it from Disks (This is called Physical IO and is much slower than logical IO)
• Log cache: I would say the bread and butter for any Sybase DBA. It stores the information about the changes made to the user data. Known as Transaction log or syslogs (actually a table). This can be viewed as a big REDO log and UNDO segment combined in Oracle. Purpose of having Log cache is RECOVERY.

About ASE Architecture: ASE's threaded kernal uses its own threading model rather than depending on Operating system.

i.e., Instead of relying on the operating system (Unlike Oracle which creates a UNIX processes for every background process) to schedule operation on a CPU or multiple CPUs, ASE takes this responsibility for itself and handles scheduling and dispatching of user threads. This makes SAP SYBASE different from other RDBMS.

More details.. I will type when I find free time.

Note:This is NOT complete or exact but should serve your purpose "I will be very much great if you guys elucidate the concepts in a Lehman terminology. As,I am in learning stage, trying to understand the basic concepts first in an easy way ".

Dear Experts, You can correct me if my understandings are wrong.

HTH

Rajesh

[DilipVoora]

Hi Rajesh,

Thanks for making me understand in such a good way by using examples .Will be anticipating for your response over the remaining.

Regards,

Dilip Voora.

[Johan_sapbasis]

Hi Dilip,

Also check the following location for information.

http://scn.sap.com/docs/DOC-36181

Sybase adminstration guide which opens in pdf format.

http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/0040e969-b4a1-2f10-998d-e0eeec6fb...

Kind Regards,

Johan

[DilipVoora]

Hi Kiran,

Sure, will look into them and in case of any queries will ask you here directly.

Regards,

Dilip Voora.

[former_member187136]

Dilip,

Superb links shared by Nicolaas.

@Dilip: I think these docs are enough to understand the basic and administration, still you have any specific questions feel free to reply in the thread so that we can reply and help you accordingly

Regards

Kiran K Adharapuram

[DilipVoora]

Thanks a lot for your response Kiran.

[former_member187136]

Hello Dilip,

Go through the documents and links I shared,also I will provide you some more stuff which explains the concepts in deeper.

Regards

Kiran K Adharapuram.

[former_member187136]

ASE uses T-SQL for its SQL Statement Execution

[former_member187136]

Dilil,

Refer to the website:

http://infocenter.Sybase.com which is a one- stop deatination for yiur reference and refer the Sybase ASE Database Administrator Guide(sag1.pdf - Google Search) - One stop Destination for all your queries.

Let me know further details I will try explaining you accordingly

Regards

Kiran K Adharapuram

[former_member187136]

Links:

http://infocenter.sybase.com/help/topic/com.sybase.infocenter.help.ase.15.7/title.htm

http://infocenter.sybase.com/help/index.jsp

[former_member187136]

Hello Dilip,

Sybase server consists of:

a) Two processes, data server and backup server.

b) Devices which house the databases; one database (master) contains system and configuration data.

c) A configuration file which contains the server attributes.

Memory Model

The Sybase memory model consists of:

a) The program area, which is where the dataserver executable is stored.

b) The data cache, stores recently fetched pages from the database device.

c) The stored procedure cache, which contains optimized sql calls.

A database device stores the objects that make up databases.

The term device does not necessarily refer to a distinct physical device: it can refer to any piece of a

disk (such as a disk partition) or a file in the file system that is used to store databases and their objects.

Each database device or file must be prepared and made known to Adaptive Server before it can be used for database

storage. This process is called initialization.

A segment is a label that points to one or more database devices.

When you first create a database, Adaptive Server creates three segments in the database,

System: Stores the databases system tables.

Logsegment: Stores the databases transaction log.

Default: Stores all other database objects

unless you create additional segments and store tables or indexes on the new segments by using create table...on segment_name or

create index...on segment_name