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Diffstat (limited to 'src/interfaces/jdbc/example/threadsafe.java')
-rw-r--r-- | src/interfaces/jdbc/example/threadsafe.java | 402 |
1 files changed, 0 insertions, 402 deletions
diff --git a/src/interfaces/jdbc/example/threadsafe.java b/src/interfaces/jdbc/example/threadsafe.java deleted file mode 100644 index cb6c0d03f2f..00000000000 --- a/src/interfaces/jdbc/example/threadsafe.java +++ /dev/null @@ -1,402 +0,0 @@ -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(); - } - } -} |