proposal: setKeepAlive

Hi,

The attached makes tcp-keep-alive enable. When PostgreSQL server gets down or
network gets down, client application can't receive any response from the server.

PostgreSQL server has GUC parameters: tcp_keepalives_* and statement_timeout,
but JDBC doesn't have such features. setQueryTimeout() is not implemented so
far, so setKeepAlive() is needed for above situation at the very least.

Best regards,

--
Toru SHIMOGAKI<shimogaki.toru@oss.ntt.co.jp>
NTT Open Source Software Center
diff -cpr postgresql-jdbc-8.3-603.src-orig/org/postgresql/core/PGStream.java
postgresql-jdbc-8.3-603.src/org/postgresql/core/PGStream.java
*** postgresql-jdbc-8.3-603.src-orig/org/postgresql/core/PGStream.java    2008-02-08 16:42:59.000000000 +0900
--- postgresql-jdbc-8.3-603.src/org/postgresql/core/PGStream.java    2008-02-08 21:29:38.000000000 +0900
*************** public class PGStream
*** 107,112 ****
--- 107,115 ----
          // really need to.
          connection.setTcpNoDelay(true);

+         // Enable tcp keep alive timer
+         connection.setKeepAlive(true);
+
          // Buffer sizes submitted by Sverre H Huseby <sverrehu@online.no>
          pg_input = new VisibleBufferedInputStream(connection.getInputStream(), 8192);
          pg_output = new BufferedOutputStream(connection.getOutputStream(), 8192);