fix: add a socket timeout on cancel requests

The timeout is configurable through cancelSignalTimeout in seconds with defult value of 10 seconds

fixes #603

pgjdbc/src/main/java/org/postgresql/PGProperty.java

@@ -250,6 +250,14 @@ public enum PGProperty {
    */
   SOCKET_TIMEOUT("socketTimeout", "0", "The timeout value used for socket read operations."),
 
+  /**
+   * Cancel command is sent out of band over its own connection, so cancel message can itself get
+   * stuck.
+   * This property controls "connect timeout" and "socket timeout" used for cancel commands.
+   * The timeout is specified in seconds. Default value is 10 seconds.
+   */
+  CANCEL_SIGNAL_TIMEOUT("cancelSignalTimeout", "10", "The timeout that is used for sending cancel command."),
+
   /**
    * Socket factory used to create socket. A null value, which is the default, means system default.
    */

pgjdbc/src/main/java/org/postgresql/core/v2/ConnectionFactoryImpl.java

@@ -132,9 +132,12 @@ public ProtocolConnection openConnectionImpl(HostSpec[] hostSpecs, String user,
         // Do authentication (until AuthenticationOk).
         doAuthentication(newStream, user, PGProperty.PASSWORD.get(info), logger);
 
+        int cancelSignalTimeout = PGProperty.CANCEL_SIGNAL_TIMEOUT.getInt(info) * 1000;
+
         // Do final startup.
         ProtocolConnectionImpl protoConnection =
-            new ProtocolConnectionImpl(newStream, user, database, logger, connectTimeout);
+            new ProtocolConnectionImpl(newStream, user, database, logger,
+                cancelSignalTimeout);
         readStartupMessages(newStream, protoConnection, logger);
 
         // Check Master or Slave

pgjdbc/src/main/java/org/postgresql/core/v2/ProtocolConnectionImpl.java

@@ -32,13 +32,13 @@
  */
 class ProtocolConnectionImpl implements ProtocolConnection {
   ProtocolConnectionImpl(PGStream pgStream, String user, String database, Logger logger,
-      int connectTimeout) {
+      int cancelSignalTimeout) {
     this.pgStream = pgStream;
     this.user = user;
     this.database = database;
     this.logger = logger;
     this.executor = new QueryExecutorImpl(this, pgStream, logger);
-    this.connectTimeout = connectTimeout;
+    this.cancelSignalTimeout = cancelSignalTimeout;
   }
 
   public HostSpec getHostSpec() {
@@ -102,7 +102,10 @@ public void sendQueryCancel() throws SQLException {
       }
 
       cancelStream =
-          new PGStream(pgStream.getSocketFactory(), pgStream.getHostSpec(), connectTimeout);
+          new PGStream(pgStream.getSocketFactory(), pgStream.getHostSpec(), cancelSignalTimeout);
+      if (cancelSignalTimeout > 0) {
+        cancelStream.getSocket().setSoTimeout(cancelSignalTimeout);
+      }
       cancelStream.SendInteger4(16);
       cancelStream.SendInteger2(1234);
       cancelStream.SendInteger2(5678);
@@ -255,6 +258,5 @@ public String getApplicationName() {
   private final String database;
   private final QueryExecutorImpl executor;
   private final Logger logger;
-
-  private final int connectTimeout;
+  private final int cancelSignalTimeout;
 }

pgjdbc/src/main/java/org/postgresql/core/v3/ConnectionFactoryImpl.java

@@ -222,9 +222,12 @@ public ProtocolConnection openConnectionImpl(HostSpec[] hostSpecs, String user,
         // Do authentication (until AuthenticationOk).
         doAuthentication(newStream, hostSpec.getHost(), user, info, logger);
 
+        int cancelSignalTimeout = PGProperty.CANCEL_SIGNAL_TIMEOUT.getInt(info) * 1000;
+
         // Do final startup.
         ProtocolConnectionImpl protoConnection =
-            new ProtocolConnectionImpl(newStream, user, database, info, logger, connectTimeout);
+            new ProtocolConnectionImpl(newStream, user, database, info, logger,
+                cancelSignalTimeout);
         readStartupMessages(newStream, protoConnection, logger);
 
         // Check Master or Slave

pgjdbc/src/main/java/org/postgresql/core/v3/ProtocolConnectionImpl.java

@@ -35,15 +35,15 @@
  */
 class ProtocolConnectionImpl implements ProtocolConnection {
   ProtocolConnectionImpl(PGStream pgStream, String user, String database, Properties info,
-      Logger logger, int connectTimeout) {
+      Logger logger, int cancelSignalTimeout) {
     this.pgStream = pgStream;
     this.user = user;
     this.database = database;
     this.logger = logger;
     this.executor = new QueryExecutorImpl(this, pgStream, info, logger);
     // default value for server versions that don't report standard_conforming_strings
     this.standardConformingStrings = false;
-    this.connectTimeout = connectTimeout;
+    this.cancelSignalTimeout = cancelSignalTimeout;
   }
 
   public HostSpec getHostSpec() {
@@ -103,7 +103,10 @@ public void sendQueryCancel() throws SQLException {
       }
 
       cancelStream =
-          new PGStream(pgStream.getSocketFactory(), pgStream.getHostSpec(), connectTimeout);
+          new PGStream(pgStream.getSocketFactory(), pgStream.getHostSpec(), cancelSignalTimeout);
+      if (cancelSignalTimeout > 0) {
+        cancelStream.getSocket().setSoTimeout(cancelSignalTimeout);
+      }
       cancelStream.SendInteger4(16);
       cancelStream.SendInteger2(1234);
       cancelStream.SendInteger2(5678);
@@ -282,8 +285,7 @@ public String getApplicationName() {
   private final String database;
   private final QueryExecutorImpl executor;
   private final Logger logger;
-
-  private final int connectTimeout;
+  private final int cancelSignalTimeout;
 
   /**
    * TimeZone of the current connection (TimeZone backend parameter)

pgjdbc/src/main/java/org/postgresql/ds/common/BaseDataSource.java

@@ -476,6 +476,22 @@ public int getSocketTimeout() {
     return PGProperty.SOCKET_TIMEOUT.getIntNoCheck(properties);
   }
 
+  /**
+   * @param seconds timeout that is used for sending cancel command
+   * @see PGProperty#CANCEL_SIGNAL_TIMEOUT
+   */
+  public void setCancelSignalTimeout(int seconds) {
+    PGProperty.CANCEL_SIGNAL_TIMEOUT.set(properties, seconds);
+  }
+
+  /**
+   * @return timeout that is used for sending cancel command in seconds
+   * @see PGProperty#CANCEL_SIGNAL_TIMEOUT
+   */
+  public int getCancelSignalTimeout() {
+    return PGProperty.CANCEL_SIGNAL_TIMEOUT.getIntNoCheck(properties);
+  }
+
 
   /**
    * @param enabled if SSL is enabled