Track sysvars that change pushdown execution

storage/xpand/ha_xpand.cc

@@ -253,7 +253,7 @@ xpand_connection *get_trx(THD *thd, int *error_code)
   xpand_connection *trx;
   if (!(trx = (xpand_connection *)thd_get_ha_data(thd, xpand_hton)))
   {
-    if (!(trx = new xpand_connection())) {
+    if (!(trx = new xpand_connection(thd))) {
       *error_code = HA_ERR_OUT_OF_MEM;
       return NULL;
     }
@@ -1264,7 +1264,7 @@ static int xpand_discover_table_names(handlerton *hton, LEX_CSTRING *db,
                                       MY_DIR *dir,
                                       handlerton::discovered_list *result)
 {
-  xpand_connection *xpand_net = new xpand_connection();
+  xpand_connection *xpand_net = new xpand_connection(NULL);
   int error_code = xpand_net->connect();
   if (error_code)
     goto err;
@@ -1278,7 +1278,7 @@ static int xpand_discover_table_names(handlerton *hton, LEX_CSTRING *db,
 
 int xpand_discover_table(handlerton *hton, THD *thd, TABLE_SHARE *share)
 {
-  xpand_connection *xpand_net = new xpand_connection();
+  xpand_connection *xpand_net = new xpand_connection(NULL);
   int error_code = xpand_net->connect();
   if (error_code)
     goto err;

storage/xpand/xpand_connection.cc

@@ -6,9 +6,15 @@ Copyright (c) 2019, MariaDB Corporation.
 
 #include "xpand_connection.h"
 #include <string>
-#include "errmsg.h"
 #include "handler.h"
 #include "table.h"
+#include "sql_class.h"
+#include "tztime.h"
+
+//#include "errmsg.h"
+//name conflicts on macro ER with sql_class.h
+#define CR_CONNECTION_ERROR 2002
+#define CR_CONN_HOST_ERROR 2003
 
 extern int xpand_connect_timeout;
 extern int xpand_read_timeout;
@@ -82,8 +88,8 @@ enum xpand_commands {
 /****************************************************************************
 ** Class xpand_connection
 ****************************************************************************/
-xpand_connection::xpand_connection()
-  : command_buffer(NULL), command_buffer_length(0), command_length(0),
+xpand_connection::xpand_connection(THD *parent_thd)
+  : session(parent_thd), command_buffer(NULL), command_buffer_length(0), command_length(0),
     trans_state(XPAND_TRANS_NONE), trans_flags(XPAND_TRANS_NO_POST_FLAGS)
 {
   DBUG_ENTER("xpand_connection::xpand_connection");
@@ -198,6 +204,43 @@ int xpand_connection::connect()
   DBUG_RETURN(0);
 }
 
+int xpand_connection::add_status_vars()
+{
+  DBUG_ENTER("xpand_connection::add_status_vars");
+  assert(session);
+
+  int error_code = 0;
+  system_variables vars = session->variables;
+  if ((error_code = add_command_operand_uchar(1)))
+    DBUG_RETURN(error_code);
+  //sql mode
+  if ((error_code = add_command_operand_ulonglong(vars.sql_mode)))
+    DBUG_RETURN(error_code);
+  //auto increment state
+  if ((error_code = add_command_operand_ushort(vars.auto_increment_increment)))
+    DBUG_RETURN(error_code);
+  if ((error_code = add_command_operand_ushort(vars.auto_increment_offset)))
+    DBUG_RETURN(error_code);
+  //character set and collation
+  if ((error_code = add_command_operand_ushort(vars.character_set_client->number)))
+    DBUG_RETURN(error_code);
+  if ((error_code = add_command_operand_ushort(vars.collation_connection->number)))
+    DBUG_RETURN(error_code);
+  if ((error_code = add_command_operand_ushort(vars.collation_server->number)))
+    DBUG_RETURN(error_code);
+  //timezone and time names
+  String tzone; //convert to utf8
+  vars.time_zone->get_name()->print(&tzone, get_charset(33,0));
+  if ((error_code = add_command_operand_str((const uchar*)tzone.ptr(),tzone.length())))
+    DBUG_RETURN(error_code);
+  if ((error_code = add_command_operand_ushort(vars.lc_time_names->number)))
+    DBUG_RETURN(error_code);
+  //transaction isolation
+  if ((error_code = add_command_operand_uchar(vars.tx_isolation)))
+    DBUG_RETURN(error_code);
+  DBUG_RETURN(0);
+}
+
 int xpand_connection::begin_command(uchar command)
 {
   if (trans_state == XPAND_TRANS_NONE)
@@ -211,6 +254,11 @@ int xpand_connection::begin_command(uchar command)
   if ((error_code = add_command_operand_uchar(trans_state | trans_flags)))
     return error_code;
 
+  if (trans_state & XPAND_TRANS_NEW_STMT ||
+      trans_state & XPAND_TRANS_REQUESTED)
+    if ((error_code = add_status_vars()))
+      return error_code;
+
   return error_code;
 }
 
@@ -620,7 +668,10 @@ class xpand_connection_cursor {
     ulong packet_length = cli_safe_read(xpand_net);
     if (packet_length == packet_error) {
       *stmt_completed = TRUE;
-      DBUG_RETURN(mysql_errno(xpand_net));
+      int error_code = mysql_errno(xpand_net);
+      my_printf_error(error_code, "Xpand error: %s", MYF(0),
+                    mysql_error(xpand_net));
+      DBUG_RETURN(error_code);
     }
 
     unsigned char *pos = xpand_net->net.read_pos;

storage/xpand/xpand_connection.h

@@ -31,6 +31,7 @@ class xpand_connection_cursor;
 class xpand_connection
 {
 private:
+  THD *session;
   MYSQL xpand_net;
   uchar *command_buffer;
   size_t command_buffer_length;
@@ -41,7 +42,7 @@ class xpand_connection
   int allocate_cursor(MYSQL *xpand_net, ulong buffer_size,
                       xpand_connection_cursor **scan);
 public:
-  xpand_connection();
+  xpand_connection(THD *parent_thd);
   ~xpand_connection();
 
   inline bool is_connected()
@@ -116,6 +117,7 @@ class xpand_connection
   int add_command_operand_vlstr(const uchar *str, size_t length);
   int add_command_operand_lex_string(LEX_CSTRING str);
   int add_command_operand_bitmap(MY_BITMAP *bitmap);
+  int add_status_vars();
   int begin_command(uchar command);
   int send_command();
   int read_query_response();