partial implementation

query_classifier/query_classifier.cc

@@ -736,15 +736,17 @@ static skygw_query_type_t resolve_query_type(
                         }
                 } /**< for */
 #if defined(TEMPORARY_TABLES)                
-                if ((skygw_query_type_t)type == QUERY_TYPE_READ)
-                {
-                        /** 
-			 * Find out the database name and all tables the query 
-			 * uses. Create a hashvalue from each and if any of the 
-			 * values can be found from property's hashtable, set 
-			 * query type to QUERY_TYPE_READ_TMP_TABLE.
-                         */
-                }
+		if ((skygw_query_type_t)type == QUERY_TYPE_READ)
+		  {
+		    /** 
+		     * Find out the database name and all tables the query 
+		     * uses. Create a hashvalue from each and if any of the 
+		     * values can be found from property's hashtable, set 
+		     * query type to QUERY_TYPE_READ_TMP_TABLE.
+		     */
+
+		  
+		  }
 #endif
         } /**< if */
 return_qtype:
@@ -874,8 +876,8 @@ char* skygw_query_classifier_get_stmtname(
 /**
 
  * Finds the head of the list of tables affected by the current select statement.
- * @param thd Pointer to a valid thread descriptor structure
- * @return Head of the TABLE_LIST chain or NULL in case of an error
+ * @param thd Pointer to a valid THD
+ * @return Pointer to the head of the TABLE_LIST chain or NULL in case of an error
  */
 void* skygw_get_affected_tables(void* thdp)
 {
@@ -893,6 +895,92 @@ void* skygw_get_affected_tables(void* thdp)
 
         return (void*)thd->lex->current_select->table_list.first;
 }
+
+
+/**
+ * Reads the parsetree and lists all the affected tables and views in the query.
+ * In the case of an error, the size of the table is set to zero and no memory is allocated.
+ * The caller must free the allocated memory.
+ *
+ * @param querybuf GWBUF where the table names are extracted from
+ * @param tblsize Pointer where the number of tables is written
+ * @return Array of null-terminated strings with the table names
+ */
+char** skygw_get_table_names(GWBUF* querybuf,int* tblsize)
+{
+  parsing_info_t* pi;
+  MYSQL*          mysql;
+  THD*            thd;
+  TABLE_LIST*     tbl;
+  SELECT_LEX*slx;
+  int i = 0, currtblsz = 0;
+  char**tables,**tmp;
+        
+  if (!GWBUF_IS_PARSED(querybuf))
+    {
+      tables = NULL;
+      goto retblock;
+    }
+  pi = (parsing_info_t *)gwbuf_get_buffer_object_data(querybuf, 
+						      GWBUF_PARSING_INFO);
+
+  if (pi == NULL)
+    {
+      tables = NULL;
+      goto retblock;                
+    }
+        
+  if (pi->pi_query_plain_str == NULL || 
+      (mysql = (MYSQL *)pi->pi_handle) == NULL || 
+      (thd = (THD *)mysql->thd) == NULL)
+    {
+      ss_dassert(pi->pi_query_plain_str != NULL &&
+		        mysql != NULL && 
+		 thd != NULL);
+      tables = NULL;
+      goto retblock;
+    }
+
+  thd->lex->current_select = thd->lex->all_selects_list;    
+
+  while(thd->lex->current_select){
+    
+    tbl = (TABLE_LIST*)skygw_get_affected_tables(thd);
+
+    while (tbl) 
+      {
+	if(i >= currtblsz){
+	  
+	  tmp = (char**)malloc(sizeof(char*)*(currtblsz*2+1));
+
+	  if(tmp){
+	    if(currtblsz > 0){
+	      int x;
+	      for(x = 0;x<currtblsz;x++){
+		tmp[x] = tables[x]; 
+	      }
+	      free(tables);
+	    }
+
+	    tables = tmp;
+	    currtblsz = currtblsz*2 + 1;
+
+	  }
+	  
+	  
+	}
+	tables[i++] = strdup(tbl->alias);
+	tbl=tbl->next_local;
+      }
+    thd->lex->current_select = thd->lex->current_select->next_select_in_list();
+  }
+
+ retblock:
+  *tblsize = i;
+  return tables;
+}
+
+
 /*
  * Replace user-provided literals with question marks. Return a copy of the
  * querystr with replacements.

query_classifier/query_classifier.h

@@ -73,6 +73,8 @@ skygw_query_type_t query_classifier_get_type(GWBUF* querybuf);
 
 /** Free THD context and close MYSQL */
 char*           skygw_query_classifier_get_stmtname(MYSQL* mysql);
+void*		skygw_get_affected_tables(void* thdp);
+char**		skygw_get_table_names(GWBUF* querybuf,int* tblsize);
 char*           skygw_get_canonical(GWBUF* querybuf);
 bool            parse_query (GWBUF* querybuf);
 parsing_info_t* parsing_info_init(void (*donefun)(void *));