diff --git a/dbcon/mysql/ha_mcs_impl.cpp b/dbcon/mysql/ha_mcs_impl.cpp
index 7cd602f9d..282bf8e0e 100644
--- a/dbcon/mysql/ha_mcs_impl.cpp
+++ b/dbcon/mysql/ha_mcs_impl.cpp
@@ -2348,8 +2348,19 @@ int ha_mcs_impl_rnd_init(TABLE* table, const std::vector<COND*>& condStack)
         return 0;
     }
 
-    //Update and delete code
-    if ( ((thd->lex)->sql_command == SQLCOM_UPDATE)  || ((thd->lex)->sql_command == SQLCOM_DELETE) || ((thd->lex)->sql_command == SQLCOM_DELETE_MULTI) || ((thd->lex)->sql_command == SQLCOM_UPDATE_MULTI))
+    /*
+      Update and delete code.
+      Note, we may be updating/deleting a different table,
+      and the current one is only needed for reading,
+      e.g. cstab1 is needed for reading in this example:
+
+      UPDATE innotab1 SET a=100 WHERE a NOT IN (SELECT a FROM cstab1 WHERE a=1);
+    */
+    if (!ci->isReadOnly() && // make sure the current table is being modified
+        (thd->lex->sql_command == SQLCOM_UPDATE ||
+         thd->lex->sql_command == SQLCOM_DELETE ||
+         thd->lex->sql_command == SQLCOM_DELETE_MULTI ||
+         thd->lex->sql_command == SQLCOM_UPDATE_MULTI))
         return doUpdateDelete(thd, gwi, condStack);
 
     uint32_t sessionID = tid2sid(thd->thread_id);
@@ -4079,6 +4090,7 @@ int ha_mcs_impl_external_lock(THD* thd, TABLE* table, int lock_type)
         return 0;
     }
 
+    ci->lock_type= lock_type;
 
     CalTableMap::iterator mapiter = ci->tableMap.find(table);
     // make sure this is a release lock (2nd) call called in
diff --git a/dbcon/mysql/ha_mcs_impl_if.h b/dbcon/mysql/ha_mcs_impl_if.h
index e9a433710..1719c8337 100644
--- a/dbcon/mysql/ha_mcs_impl_if.h
+++ b/dbcon/mysql/ha_mcs_impl_if.h
@@ -262,7 +262,8 @@ struct cal_connection_info
         utf8(false),
         useCpimport(1),
         delimiter('\7'),
-        affectedRows(0)
+        affectedRows(0),
+        lock_type(F_UNLCK)
     {
         // check if this is a slave mysql daemon
         isSlaveNode = checkSlave();
@@ -285,6 +286,11 @@ struct cal_connection_info
         return true;
     }
 
+    bool isReadOnly() const
+    {
+        return lock_type == F_RDLCK;
+    }
+
     sm::cpsm_conhdl_t* cal_conn_hndl;
     std::stack<sm::cpsm_conhdl_t*> cal_conn_hndl_st;
     int queryState;
@@ -335,6 +341,7 @@ struct cal_connection_info
     // MCOL-1101 remove compilation unit variable rmParms
     std::vector <execplan::RMParam> rmParms;
     long long affectedRows;
+    int lock_type;
 };
 
 const std::string infinidb_err_msg = "\nThe query includes syntax that is not supported by MariaDB Columnstore. Use 'show warnings;' to get more information. Review the MariaDB Columnstore Syntax guide for additional information on supported distributed syntax or consider changing the MariaDB Columnstore Operating Mode (infinidb_vtable_mode).";