Introduction to Sybase
Sybase completely focuses on mobilizing and managing information. it’s acknowledged to be the third largest management company after Oracle and IBM. Sybase products on Investment banking are well known to the world over and it offers several customized solutions for business intelligence.
Basic Things you will study in this Tutorial;
Features
Update statistics in Sybase
Criticism about Sybase IQ
Replication Server and SQL Remote in Sybase
Features
- User-defined SQL functions.
- Statistical aggregate functions.
- Row-locked system catalogs.
- Augmented security and encryption.
- SQL statement replication.
- QP Tune tuning utility.
- Shared-disk clustering.
Update statistics in Sybase
The update statistics command helps the server create the simplest selections concerning that indexes to use once it processes a question , by providing information concerning the distribution of the key values within the indexes. The update statistics commands produce statistics, if there are not any statistics for a selected column, or replaces existing statistics if they exist already. The statistics are stored in the system tables.
Criticism about Sybase IQ
Sybase storage systems are optimized for Dataware housing applications wherever information can’t be changed are often changed by looking out and accessing the information. It is column based mostly search criteria provides high performance for search however it negates the writing capability to the information. Performance for row relative based databases is worse because it is tough for updating and modifying them.
Replication Server and SQL Remote in Sybase
Both SQL Remote and Replication Server perform replication. SQL Remote was originally a part of the Adaptive Server anywhere tool kit and is meant for intermittent replication. Replication Server is intended for near real-time replication scenarios.
Differnces between an LTM and a RepAgent in Sybase
Log Transfer Managers (LTMs) and RepAgents are the processes that transfer data between ASE and the Replication Server.
•LTMs were delivered with the first releases of Replication Server. Each LTM is a separate process at the operating system level that runs along side ASE and Replication Server. As with ASE and Replication Server, a RUN_ and configuration file is required for each LTM. One LTM is required for each database being replicated.
•Along with ASE 11.5 a new concept was introduced, RepAgents might refer to earlier versions of Replication Server. Every RepAgent is a slot-in replacement for associate LTM. However, rather than running as separate software package method, it runs as a thread among ASE. Just about all of the wants for Replication server and associate LTM which is apply to the RepAgents. One per information being replicated, etc. however currently which you are doing for that no need to separate configuration files.
Replicate side in Sybase
Sybase replication works by taking every transaction that happens within the primary dataserver and applying to the replicate. Since replication works on the group action log, a single, atomic, update on the first side that updates a million rows are going to be translated into a million single row updates. This could appear terribly strange however may be a easy consequence of however it works. On the first, this million row update can plan to increase the locks that it’s taken intent on exclusive table lock.
•However, on the replicate side every row is updated severally, very much like if they were being updated inside a pointer loop. Now, Sybase tries to increase locks from one atomic statement (see ASE Qx.y), thus it will never try and increase the lock. However, since the updates are unit taking place with in a single transaction, Sybase can ought to do away with enough page locks to lock the million rows.
Sybase
has worlds leading products some of them are
ASE
Avantgo
Power builder and power designer
SQL ianywhere
Sybase IQ
Sybase replication server
Sybase RTE
Sybase information federation
Main frame connect
Replication Server on unix in Sybase
It is a decent follow with production installations of Replication Server on Unix that you use raw partitions for the stable devices. This is often for simply an equivalent reason that production ASE’s use raw partitions. Raw devices are often a most of 2GB with replication server up to release 11.5.
In order to apply a raw partition that’s larger than 2GB in size you’ll be able to do the subsequent (remember all of the cautionary warnings concerning making an attempt this type of stuff move into development first!):
add partition firstpartition on ‘/dev/rdsk/c0t0d0s0’ with size 2024go
add partition secondpartition on ‘/dev/rdsk/c0t0d0s0’ with size 2024
starting at 2048
go
Notice that the initial partition is sized at 2024MB and not 2048. I actually have not found this within the documentation, however replication actually looks to own a drag allocating a full 2GB. apparently, do an equivalent operation through Rep Server Manager and Sybase central caused no issues at all.
Drawbacks of normalization
Although most successful databases are normalized to some extent, there is one substantial downside of a normalized information: reduced database performance. The acceptance of reduced performance needs the data that once a query or transaction request is distributed to the information, there are factors involved, like mainframe usage, memory usage, and input/output (I/O). A normalized information needs rather more mainframe, memory, and I/O to method transactions and information queries for a denormalized information.
•A normalized information should find the requested tables so be a part of information from the tables to either get the requested information or the method which contains specified data. A additional in-depth discussion regarding information performance happens in Hour 18, “Managing Database Users.”
Stored procedure
Stored procedure is a database object which is collection of SQL statements or constructs. Parameters are often passed and came back, and error codes is also checked. Stored procedures, after their first execution, become memory resident and don’t ought to be reparsed, reoptimized, or recompiled. So, they are faster.
Structure of Adaptive Server Enterprise
Structure of ASE installation hosts many databases and it comprises of one data server. Additionally system files occupy just one meta data. User databases are stored in the form of tables. Security and data privacy can be protected by setting permissions.