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From "Tomohito Nakayama (JIRA)" <derby-...@db.apache.org>
Subject [jira] Commented: (DERBY-550) BLOB : java.lang.OutOfMemoryError with network JDBC driver (org.apache.derby.jdbc.ClientDriver)
Date Sat, 15 Jul 2006 05:52:15 GMT
    [ http://issues.apache.org/jira/browse/DERBY-550?page=comments#action_12421279 ] 
            
Tomohito Nakayama commented on DERBY-550:
-----------------------------------------

My consideration is that ByteArrayOutputStream should not be used for large data, especially
the size is unknown.

When program retrieve data from ByteArrayOutputStream object, it is needed to allocate another
memory other than instance variable byte[]buf of ByteArrayOutputStream.
Because ByteArrayOutputStream.buf does not have same length to the data of whch  program passed
to ByteArrayOutputStream object.

When the size of data is known, we can escape this problem 
because we can fix the size of the ByteArrayOutputStream.buf to the size of data at construction
time of ByteArrayOutputStream instance, and we can escape allocating another memory just using
ByteArrayOutputStream.buf directly.

> BLOB : java.lang.OutOfMemoryError with network JDBC driver (org.apache.derby.jdbc.ClientDriver)
> -----------------------------------------------------------------------------------------------
>
>                 Key: DERBY-550
>                 URL: http://issues.apache.org/jira/browse/DERBY-550
>             Project: Derby
>          Issue Type: Bug
>          Components: JDBC, Network Server
>    Affects Versions: 10.1.1.0
>         Environment: Any environment.
>            Reporter: Grégoire Dubois
>         Assigned To: Tomohito Nakayama
>         Attachments: BlobOutOfMem.java
>
>
> Using the org.apache.derby.jdbc.ClientDriver driver to access the
> Derby database through network, the driver is writting all the file into memory (RAM)
before sending
> it to the database.
> Writting small files (smaller than 5Mo) into the database works fine,
> but it is impossible to write big files (40Mo for example, or more), without getting
the
> exception java.lang.OutOfMemoryError.
> The org.apache.derby.jdbc.EmbeddedDriver doesn't have this problem.
> Here follows some code that creates a database, a table, and trys to write a BLOB. 2
parameters are to be changed for the code to work for you : DERBY_DBMS_PATH and FILE
> import NetNoLedge.Configuration.Configs;
> import org.apache.derby.drda.NetworkServerControl;
> import java.net.InetAddress;
> import java.io.*;
> import java.sql.*;
> /**
>  *
>  * @author  greg
>  */
> public class DerbyServer_JDBC_BLOB_test {
>     
>     // The unique instance of DerbyServer in the application.
>     private static DerbyServer_JDBC_BLOB_test derbyServer;
>     
>     private NetworkServerControl server;
>     
>     private static final String DERBY_JDBC_DRIVER = "org.apache.derby.jdbc.ClientDriver";
>     private static final String DERBY_DATABASE_NAME = "Test";
>     
>     // ###############################################################
>     // ############### SET HERE THE EXISTING PATH YOU WANT ################
>     // ###############################################################
>     private static final String DERBY_DBMS_PATH =  "/home/greg/DatabaseTest";
>     // ###############################################################
>     // ###############################################################
>     
>     
>     private static int derbyPort = 9157;
>     private static String userName = "user";
>     private static String userPassword = "password";
>     
>     // ###################################################################################
>     // ############# DEFINE HERE THE PATH TO THE FILE YOU WANT TO WRITE INTO THE DATABASE
###########
>     // ############# TRY A 100kb-3Mb FILE, AND AFTER A 40Mb OR BIGGER FILE #########################
>     // ###################################################################################
>     private static final File FILE = new File("/home/greg/01.jpg");
>     // ###################################################################################
>     // ###################################################################################
>     
>     /**
>      * <p>Used to test the server.
>      */
>     public static void main(String args[]) {
>         try {
>             DerbyServer_JDBC_BLOB_test.launchServer();
>             DerbyServer_JDBC_BLOB_test server = getUniqueInstance();
>             server.start();
>             System.out.println("Server started");
>         
>             // After the server has been started, launch a first connection to the database
to
>             // 1) Create the database if it doesn't exist already,
>             // 2) Create the tables if they don't exist already.            
>             Class.forName(DERBY_JDBC_DRIVER).newInstance();
>             Connection connection = DriverManager.getConnection ("jdbc:derby://localhost:"+derbyPort+"/"+DERBY_DATABASE_NAME+";create=true",
userName, userPassword);
>             System.out.println("Network JDBC connection to Derby succeded. Database created
if not created already.");
>             
>             Statement statement = connection.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
>             Statement statement2;
>             // Create the table "file" if it doesn't already exist.
>             String [] tableNames={"file"};
>             boolean exist;
>             String currentTable;
>             ResultSet result = statement.executeQuery("SELECT TABLENAME FROM SYS.SYSTABLES");
>             for (int i=0;i<tableNames.length;i++) {
>                 exist=false;
>                 while (result.next()){
>                     if (tableNames[i].equalsIgnoreCase(result.getString(1)))
>                         exist=true;
>                 }
>             
>                 if (!exist) {
>                     statement2 = connection.createStatement();
>                     statement2.execute("CREATE TABLE file (" +
>                     "file BLOB(2G) NOT NULL)");
>                     connection.commit();
>                 }
>                 result.beforeFirst();
>             }
>             System.out.println("Table file created if not created already");
>             
>             System.out.println("File insertion into BLOB");
>             FileInputStream inputStream = new FileInputStream(FILE);
>             PreparedStatement   preparedStatement = connection.prepareStatement("INSERT
INTO file(file) VALUES (?)");
>             preparedStatement.setBinaryStream(1,inputStream,(int) FILE.length());
>             preparedStatement .execute();
>             connection.commit();
>             System.out.println("File inserted into BLOB");
>         }
>         catch (Exception e) {
>             e.printStackTrace();
>         }
>     }
>     
>     /** Creates a new instance of MckoiServer
>      * Password is used at the database creation. It will be the database password once
created.
>      */    
>     private DerbyServer_JDBC_BLOB_test() throws Exception {
>         System.setProperty("derby.system.home", DERBY_DBMS_PATH);
>         
>         // Set the server to request an authentification.
>         System.setProperty("derby.authentication.provider", "BUILTIN");
>         System.setProperty("derby.connection.requireAuthentication", "true");
>         
>         // Create a user that can connect to Derby.
>         System.setProperty("derby.user."+userName, userPassword);
>         
>         // Set Derby to grant full access to the created user (to all the databases).
>         System.setProperty("derby.database.fullAccessUsers", userName);
>         
>         //System.setProperty("derby.system.bootAll", "true");
>         
>         // See if the 9157 port is already taken.
>         // Change it if necessary.
>         boolean isPortFree = false;
>         while ( !isPortFree ) {
>             try {
>                 java.net.ServerSocket serverTest = new java.net.ServerSocket(derbyPort);
>                 serverTest.close();
>                 serverTest = null;
>                 
>                 isPortFree = true;
>             }
>             catch (Exception e) {
>                 System.out.println("Port already in use : "+derbyPort);
>                 derbyPort++;
>                 System.out.println("Try with port "+derbyPort);
>             }
>         }     
>         
>         server = new NetworkServerControl(InetAddress.getByName("localhost"),derbyPort);
>     }
>     
>     public static void launchServer() throws Exception {
>         derbyServer = new DerbyServer_JDBC_BLOB_test();
>     }
>     
>     public static DerbyServer_JDBC_BLOB_test getUniqueInstance() {
>         return derbyServer;
>     }
>     
>     /**
>      * <p>Start the server.
>      */
>     public void start() {
>         try {
>             server.start(null);
>         }
>         catch (Exception e) {
>             e.printStackTrace(System.err);
>         }
>     }
>     
>     /**
>      * <p>Stop the server.
>      */
>     public void stop() {
>         try {
>             server.shutdown();
>         }
>         catch (Exception e) {
>             e.printStackTrace(System.err);
>         }
>     }
> }

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