Set the execution status to ASYNC_READ after flushing all output.

Without this a query that did not get flushed completely to the server
would cause cursor.poll() to always go into the curs_poll_send()
branch even if it was retuning ASYNC_READ.

Bug report by Daniele Varrazzo.

psycopg/connection.h

@@ -51,6 +51,7 @@ extern "C" {
 #define CONN_STATUS_GET_CLIENT_ENCODING        10
 
 /* async query execution status */
+#define ASYNC_DONE  0
 #define ASYNC_READ  1
 #define ASYNC_WRITE 2
 

psycopg/connection_type.c

@@ -695,6 +695,7 @@ connection_setup(connectionObject *self, const char *dsn, long int async)
     self->status = async ? CONN_STATUS_SETUP : CONN_STATUS_READY;
     self->critical = NULL;
     self->async_cursor = NULL;
+    self->async_status = ASYNC_DONE;
     self->pgconn = NULL;
     self->mark = 0;
     self->string_types = PyDict_New();

psycopg/cursor_int.c

@@ -112,6 +112,7 @@ curs_poll_send(cursorObject *self)
     else if (res == 0) {
         /* all data flushed, start waiting for results */
         Dprintf("cur_poll_send: returning %d", PSYCO_POLL_READ);
+        self->conn->async_status = ASYNC_READ;
         return PyInt_FromLong(PSYCO_POLL_READ);
     }
     else {
@@ -153,6 +154,11 @@ curs_poll_fetch(cursorObject *self)
 
     if (last_result == 0) {
         Dprintf("cur_poll_fetch: returning %d", PSYCO_POLL_OK);
+        /* self->conn->async_status cannot be ASYNC_WRITE here, because we
+           never execute curs_poll_fetch in ASYNC_WRITE state, so we can
+           safely set it to ASYNC_DONE because we either fetched the result or
+           there is no result to fetch */
+        self->conn->async_status = ASYNC_DONE;
         return PyInt_FromLong(PSYCO_POLL_OK);
     }
     else if (last_result == 1) {

psycopg/cursor_type.c

@@ -1491,7 +1491,10 @@ psyco_curs_poll(cursorObject *self)
     if (self->conn->async_status == ASYNC_WRITE) {
         return curs_poll_send(self);
     }
-    else  {
+    else {
+        /* this gets called both for ASYNC_READ and ASYNC_DONE, because even
+           if the async query is complete, we still might want to check for
+           NOTIFYs */
         return curs_poll_fetch(self);
     }
 }