Helpless

Java Simple Tail

2011-02-23T11:57:00.004+07:00

Many time we need to see application log but not for all log but for last line or -n line. As wee know tail in *NIX,solaris,etc have function like tail [-f] filename. And how if we make this future with JAVA code. This time i only give you a simple tail basic function that you have to extend it Here is the code:


 public String seek( String fileName , int line) {
  try {
         java.io.File file = new java.io.File( fileName );
      
         if( !file.exists() ){
          System.out.println("File Not Found");
          System.exit(0);
         }
         RandomAccessFile fileHandler = new RandomAccessFile( file, "r" );
         long fileLength = file.length() - 1;
         int newLineCount = 0;
         int carrierLineCount = 0;
         StringBuilder sb = new StringBuilder();
 
         for( long filePointer = fileLength; filePointer != -1; filePointer-- ) {
             fileHandler.seek( filePointer );
             int readByte = fileHandler.readByte();
             if( readByte == 0xA ) {              
              if( filePointer == fileLength ) {                  
                     continue;
                 } else {
                  newLineCount++;
                  if( newLineCount == line )
                   break;
              }
             } else if( readByte == 0xD ) {              
              if( filePointer == fileLength - 1 ) {
                  continue;
                 } else{                  
                  carrierLineCount++;
                  if( carrierLineCount == line )
                   break;
              }          
             }
             sb.append( ( char ) readByte );
         }
 
         String lastLine = sb.reverse().toString();
         return lastLine;
     } catch( java.io.FileNotFoundException e ) {
         e.printStackTrace();
         return null;
     } catch( java.io.IOException e ) {
         e.printStackTrace();
         return null;
     }
 }

Oracle Workforce Development Program

2008-12-12T08:59:00.003+07:00

In the year 2005 I decided to get Oracle course with Oracle Workforce Development Program (WDP). I take course with SQL Fundamental and Administration Workshop (to get OCA certificate). Event today my company not used Oracle as their databases but I still want to studying Oracle.

In a long period I search an e-book about Oracle (event I have Oracle book) and now it all was pay. I founded that book with lab script, unfortunately for SQL Fundamentals I’m not found for lab script.

This book is same as Oracle WDP program used in their courses, so you get the same case as the courses. Here I will list where you can download the book:

Notes:

For encrypted files, the password is `www.eftekasat.net`

Oracle Memory Structure

2008-12-12T08:52:00.003+07:00

The basic memory structures associated with an Oracle instance include:

System Global Area (SGA): Shared by all server and background process.

Program Global Area (PGA): Private to each server and background process; there is one PGA for each process.

The System Global Area (SGA) is a shared memory area that contains data and control information for the instance.
The SGA includes the following data structures:

Database buffer cache: Caches block of data retrieved from database

Redo log buffer: Caches redo information (used for instance recovery) until it can be written to the physical redo log files store on disk

Shared pool: Caches various constructs that can be shared among users

Large pool: Optional area used for buffering large I/O request

Java pool: Used for all session-specific Java code and data within the Java Virtual Machine (JVM)

Stream pool: Used by Oracle Streams

With the dynamic SGA infrastructure, the size of the database buffer cache, the shared pool, the large pool, the Java pool, and the Stream pool changes without shutting down the instance.
The preconfigured database has been pretuned with adequate setting for the memory parameters. However, as your database usage expands your may find it necessary to alter the setting of the memory parameters.
Oracle provides alerts and advisors to identify memory sizing problems and to help you determine appropriate values for memory parameters.
A Program Global Area (PGA) is a memory region which contains data and control information for each server process. A server process is a process that services a client’s request. Each server process has it own private PGA area that is created when the server process is started. Access to it is exclusive to that server process, and is read and written only by Oracle code acting on behalf of it.
The amount of PGA memory used and its content depends on weather the instance is configured in shared server mode. Generally, the PGA contains the following:

Private SQL area: Contains data such as bind information and run-time memory structures. Each session that issues a SQL statement has a private SQL area.

Session memory: Memory allocated ti hold session variables and other information related to the session.

Oracle Instance Management

2008-12-11T10:04:00.004+07:00

An Oracle database server consists of an Oracle database and Oracle instance. An Oracle instance is made up of memory buffers known as the System Global Area (SGA) and background process that handle much of the behind-the-scenes work involved in running an instance.
The instance is idle(nonexistent) until it is started. When the instance is started, an initialization parameter file is read and the instance is configured according to instructions contained within the parameter file.
After the instance is started and the database is opened, user can access the database.

Optimal Flexible Architecture (OFA)

2008-12-11T09:49:00.001+07:00

OFA is a methode for configuring the Oracle database and other database. OFA takes the advantage of the OS and disk subsystems capabilities to create an easy-to-administer configuration that allows maximum flexibilitiy for growing and high-performance database. the methodes described here are basics of OFA.

OFA is designed to:

Organize large amounts of complicated software and data on disk, to avoid device bottleneck and poor performance.
Facilitate routine administrative tasks such as software and data backup, which are often vulnerrable to data corruption.
facilitate switching between multiple Oracle databases.
Adequately manage and administer database growth.
Help eliminate fragmentation of free space in the data dictionary, isolate other fragmentation, and minimize resource contention.