ssl-write-retry-3.patch

diff --git a/src/interfaces/libpq/fe-misc.c b/src/interfaces/libpq/fe-misc.c
index 17dde4a..977e37c 100644
--- a/src/interfaces/libpq/fe-misc.c
+++ b/src/interfaces/libpq/fe-misc.c
@@ -793,20 +793,26 @@ pqSendSome(PGconn *conn, int len)
 	while (len > 0)
 	{
 		int			sent;
+		int			write_size = len;
 		char		sebuf[256];
 
-#ifndef WIN32
-		sent = pqsecure_write(conn, ptr, len);
-#else
-
+#ifdef WIN32
 		/*
 		 * Windows can fail on large sends, per KB article Q201213. The
 		 * failure-point appears to be different in different versions of
 		 * Windows, but 64k should always be safe.
 		 */
-		sent = pqsecure_write(conn, ptr, Min(len, 65536));
+		write_size = Min(len, 65536);
+#endif
+
+#ifdef USE_SSL
+		/* We have leftovers from previous SSL write, send these first. */
+		if (conn->ssl_retry_bytes)
+			write_size = conn->ssl_retry_bytes;
 #endif
 
+		sent = pqsecure_write(conn, ptr, write_size);
+
 		if (sent < 0)
 		{
 			/*
@@ -857,11 +863,30 @@ pqSendSome(PGconn *conn, int len)
 					return -1;
 			}
 		}
+#ifdef USE_SSL
+		else if (sent == 0)
+		{
+			/*
+			 * We are in non-blocking mode, set up for retrying a SSL write
+			 * operation. OpenSSL requires the same buffer to be passed to the
+			 * write retry, so we must remember the write size. However, we
+			 * don't need to keep the original buffer address as the 
+			 * SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER mode ought to be set.
+			 */
+			if (!conn->ssl_retry_bytes)
+				conn->ssl_retry_bytes = write_size;
+		}
+#endif
 		else
 		{
 			ptr += sent;
 			len -= sent;
 			remaining -= sent;
+#ifdef USE_SSL
+			/* Forget the retry buffer size if all the data has been sent */
+			if (conn->ssl_retry_bytes)
+				conn->ssl_retry_bytes = 0;
+#endif
 		}
 
 		if (len > 0)
diff --git a/src/interfaces/libpq/fe-secure.c b/src/interfaces/libpq/fe-secure.c
index cd1292c..540561d 100644
--- a/src/interfaces/libpq/fe-secure.c
+++ b/src/interfaces/libpq/fe-secure.c
@@ -757,6 +757,9 @@ init_ssl_system(PGconn *conn)
 #endif
 			return -1;
 		}
+
+		/* Enable moving write buffer to simplify write retry handling. */
+		SSL_CTX_set_mode(SSL_context, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
 	}
 
 #ifdef ENABLE_THREAD_SAFETY
diff --git a/src/interfaces/libpq/libpq-int.h b/src/interfaces/libpq/libpq-int.h
index d56ef5d..ae212a6 100644
--- a/src/interfaces/libpq/libpq-int.h
+++ b/src/interfaces/libpq/libpq-int.h
@@ -407,6 +407,8 @@ struct pg_conn
 	X509	   *peer;			/* X509 cert of server */
 	char		peer_dn[256 + 1];		/* peer distinguished name */
 	char		peer_cn[SM_USER + 1];	/* peer common name */
+
+	int			ssl_retry_bytes;	/* buffer size for SSL write retry */
 #ifdef USE_SSL_ENGINE
 	ENGINE	   *engine;			/* SSL engine, if any */
 #else