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-package example;
-
-import java.io.*;
-import java.sql.*;
-
-// rare in user code, but we use the LargeObject API in this test
-import org.postgresql.largeobject.*;
-
-/*
- * This example tests the thread safety of the driver.
- *
- * It does this by performing several queries, in different threads. Each
- * thread has it's own Statement object, which is (in my understanding of the
- * jdbc specification) the minimum requirement.
- *
- */
-
-public class threadsafe
-{
- Connection db; // The connection to the database
- Statement st; // Our statement to run queries with
-
- public threadsafe(String args[]) throws ClassNotFoundException, FileNotFoundException, IOException, SQLException
- {
- String url = args[0];
- String usr = args[1];
- String pwd = args[2];
-
- // Load the driver
- Class.forName("org.postgresql.Driver");
-
- // Connect to database
- System.out.println("Connecting to Database URL = " + url);
- db = DriverManager.getConnection(url, usr, pwd);
-
- System.out.println("Connected...Now creating a statement");
- st = db.createStatement();
-
- // Clean up the database (in case we failed earlier) then initialise
- cleanup();
-
- // Because we use LargeObjects, we must use Transactions
- db.setAutoCommit(false);
-
- // Now run tests using JDBC methods, then LargeObjects
- doexample();
-
- // Clean up the database
- cleanup();
-
- // Finally close the database
- System.out.println("Now closing the connection");
- st.close();
- db.close();
- }
-
- /*
- * This drops the table (if it existed). No errors are reported.
- */
- public void cleanup()
- {
- try
- {
- st.executeUpdate("drop table basic1");
- }
- catch (Exception ex)
- {
- // We ignore any errors here
- }
-
- try
- {
- st.executeUpdate("drop table basic2");
- }
- catch (Exception ex)
- {
- // We ignore any errors here
- }
- }
-
- /*
- * This performs the example
- */
- public void doexample() throws SQLException
- {
- System.out.println("\nThis test runs three Threads. Two simply insert data into a table, then\nthey perform a query. While they are running, a third thread is running,\nand it load data into, then reads from a Large Object.\n\nIf alls well, this should run without any errors. If so, we are Thread Safe.\nWhy test JDBC & LargeObject's? Because both will run over the network\nconnection, and if locking on the stream isn't done correctly, the backend\nwill get pretty confused!\n");
-
- thread3 thread3 = null;
-
- try
- {
-
- // create the two threads
- Thread thread0 = Thread.currentThread();
- Thread thread1 = new thread1(db);
- Thread thread2 = new thread2(db);
- thread3 = new thread3(db);
-
- // now run, and wait for them
- thread1.start();
- thread2.start();
- thread3.start();
-
- // ok, I know this is bad, but it does the trick here as our main thread
- // will yield as long as either of the children are still running
- System.out.println("Waiting for threads to run");
- while (thread1.isAlive() || thread2.isAlive() || thread3.isAlive())
- Thread.yield();
- }
- finally
- {
- // clean up after thread3 (the finally ensures this is run even
- // if an exception is thrown inside the try { } construct)
- if (thread3 != null)
- thread3.cleanup();
- }
-
- System.out.println("No Exceptions have been thrown. This is a good omen, as it means that we are\npretty much thread safe as we can get.");
- }
-
- // This is the first thread. It's the same as the basic test
- class thread1 extends Thread
- {
- Connection c;
- Statement st;
-
- public thread1(Connection c) throws SQLException
- {
- this.c = c;
- st = c.createStatement();
- }
-
- public void run()
- {
- try
- {
- System.out.println("Thread 1 running...");
-
- // First we need a table to store data in
- st.executeUpdate("create table basic1 (a int2, b int2)");
-
- // Now insert some data, using the Statement
- st.executeUpdate("insert into basic1 values (1,1)");
- st.executeUpdate("insert into basic1 values (2,1)");
- st.executeUpdate("insert into basic1 values (3,1)");
-
- // For large inserts, a PreparedStatement is more efficient, because it
- // supports the idea of precompiling the SQL statement, and to store
- // directly, a Java object into any column. PostgreSQL doesnt support
- // precompiling, but does support setting a column to the value of a
- // Java object (like Date, String, etc).
- //
- // Also, this is the only way of writing dates in a datestyle independent
- // manner. (DateStyles are PostgreSQL's way of handling different methods
- // of representing dates in the Date data type.)
- PreparedStatement ps = db.prepareStatement("insert into basic1 values (?,?)");
- for (int i = 2;i < 2000;i++)
- {
- ps.setInt(1, 4); // "column a" = 5
- ps.setInt(2, i); // "column b" = i
- ps.executeUpdate(); // executeUpdate because insert returns no data
- // c.commit();
- if ((i % 50) == 0)
- DriverManager.println("Thread 1 done " + i + " inserts");
- }
- ps.close(); // Always close when we are done with it
-
- // Finally perform a query on the table
- DriverManager.println("Thread 1 performing a query");
- ResultSet rs = st.executeQuery("select a, b from basic1");
- int cnt = 0;
- if (rs != null)
- {
- // Now we run through the result set, printing out the result.
- // Note, we must call .next() before attempting to read any results
- while (rs.next())
- {
- int a = rs.getInt("a"); // This shows how to get the value by name
- int b = rs.getInt(2); // This shows how to get the value by column
- //System.out.println(" a="+a+" b="+b);
- cnt++;
- }
- rs.close(); // again, you must close the result when done
- }
- DriverManager.println("Thread 1 read " + cnt + " rows");
-
- // The last thing to do is to drop the table. This is done in the
- // cleanup() method.
- System.out.println("Thread 1 finished");
- }
- catch (SQLException se)
- {
- System.err.println("Thread 1: " + se.toString());
- se.printStackTrace();
- System.exit(1);
- }
- }
- }
-
- // This is the second thread. It's the similar to the basic test, and thread1
- // except it works on another table.
- class thread2 extends Thread
- {
- Connection c;
- Statement st;
-
- public thread2(Connection c) throws SQLException
- {
- this.c = c;
- st = c.createStatement();
- }
-
- public void run()
- {
- try
- {
- System.out.println("Thread 2 running...");
-
- // First we need a table to store data in
- st.executeUpdate("create table basic2 (a int2, b int2)");
-
- // For large inserts, a PreparedStatement is more efficient, because it
- // supports the idea of precompiling the SQL statement, and to store
- // directly, a Java object into any column. PostgreSQL doesnt support
- // precompiling, but does support setting a column to the value of a
- // Java object (like Date, String, etc).
- //
- // Also, this is the only way of writing dates in a datestyle independent
- // manner. (DateStyles are PostgreSQL's way of handling different methods
- // of representing dates in the Date data type.)
- PreparedStatement ps = db.prepareStatement("insert into basic2 values (?,?)");
- for (int i = 2;i < 2000;i++)
- {
- ps.setInt(1, 4); // "column a" = 5
- ps.setInt(2, i); // "column b" = i
- ps.executeUpdate(); // executeUpdate because insert returns no data
- // c.commit();
- if ((i % 50) == 0)
- DriverManager.println("Thread 2 done " + i + " inserts");
- }
- ps.close(); // Always close when we are done with it
-
- // Finally perform a query on the table
- DriverManager.println("Thread 2 performing a query");
- ResultSet rs = st.executeQuery("select * from basic2 where b>1");
- int cnt = 0;
- if (rs != null)
- {
- // First find out the column numbers.
- //
- // It's best to do this here, as calling the methods with the column
- // numbers actually performs this call each time they are called. This
- // really speeds things up on large queries.
- //
- int col_a = rs.findColumn("a");
- int col_b = rs.findColumn("b");
-
- // Now we run through the result set, printing out the result.
- // Again, we must call .next() before attempting to read any results
- while (rs.next())
- {
- int a = rs.getInt(col_a); // This shows how to get the value by name
- int b = rs.getInt(col_b); // This shows how to get the value by column
- //System.out.println(" a="+a+" b="+b);
- cnt++;
- }
- rs.close(); // again, you must close the result when done
- }
- DriverManager.println("Thread 2 read " + cnt + " rows");
-
- // The last thing to do is to drop the table. This is done in the
- // cleanup() method.
- System.out.println("Thread 2 finished");
- }
- catch (SQLException se)
- {
- System.err.println("Thread 2: " + se.toString());
- se.printStackTrace();
- System.exit(1);
- }
- }
- }
-
- // This is the third thread. It loads, then reads from a LargeObject, using
- // our LargeObject api.
- //
- // The purpose of this is to test that FastPath will work in between normal
- // JDBC queries.
- class thread3 extends Thread
- {
- Connection c;
- Statement st;
- LargeObjectManager lom;
- LargeObject lo;
- int oid;
-
- public thread3(Connection c) throws SQLException
- {
- this.c = c;
- //st = c.createStatement();
-
- // create a blob
- lom = ((org.postgresql.PGConnection)c).getLargeObjectAPI();
- oid = lom.create();
- System.out.println("Thread 3 has created a blob of oid " + oid);
- }
-
- public void run()
- {
- try
- {
- System.out.println("Thread 3 running...");
-
- DriverManager.println("Thread 3: Loading data into blob " + oid);
- lo = lom.open(oid);
- FileInputStream fis = new FileInputStream("example/threadsafe.java");
- // keep the buffer size small, to allow the other thread a chance
- byte buf[] = new byte[128];
- int rc, bc = 1, bs = 0;
- while ((rc = fis.read(buf)) > 0)
- {
- DriverManager.println("Thread 3 read block " + bc + " " + bs + " bytes");
- lo.write(buf, 0, rc);
- bc++;
- bs += rc;
- }
- lo.close();
- fis.close();
-
- DriverManager.println("Thread 3: Reading blob " + oid);
- lo = lom.open(oid);
- bc = 0;
- while (buf.length > 0)
- {
- buf = lo.read(buf.length);
- if (buf.length > 0)
- {
- String s = new String(buf);
- bc++;
- DriverManager.println("Thread 3 block " + bc);
- DriverManager.println("Block " + bc + " got " + s);
- }
- }
- lo.close();
-
- System.out.println("Thread 3 finished");
- }
- catch (Exception se)
- {
- System.err.println("Thread 3: " + se.toString());
- se.printStackTrace();
- System.exit(1);
- }
- }
-
- public void cleanup() throws SQLException
- {
- if (lom != null && oid != 0)
- {
- System.out.println("Thread 3: Removing blob oid=" + oid);
- lom.delete(oid);
- }
- }
- }
-
- /*
- * Display some instructions on how to run the example
- */
- public static void instructions()
- {
- System.out.println("\nThis tests the thread safety of the driver.\n\nThis is done in two parts, the first with standard JDBC calls, and the\nsecond mixing FastPath and LargeObject calls with queries.\n");
- System.out.println("Useage:\n java example.threadsafe jdbc:postgresql:database user password [debug]\n\nThe debug field can be anything. It's presence will enable DriverManager's\ndebug trace. Unless you want to see screens of items, don't put anything in\nhere.");
- System.exit(1);
- }
-
- /*
- * This little lot starts the test
- */
- public static void main(String args[])
- {
- System.out.println("PostgreSQL Thread Safety test v6.4 rev 1\n");
-
- if (args.length < 3)
- instructions();
-
- // This line outputs debug information to stderr. To enable this, simply
- // add an extra parameter to the command line
- if (args.length > 3)
- DriverManager.setLogStream(System.err);
-
- // Now run the tests
- try
- {
- threadsafe test = new threadsafe(args);
- }
- catch (Exception ex)
- {
- System.err.println("Exception caught.\n" + ex);
- ex.printStackTrace();
- }
- }
-}