MySQL：如何编写Information Schema Plugin(11)

 const char *key; 

 size_t key_length; 

/*引用query_cache全局变量*/ 

  qc= (Accessible_Query_Cache *)&query_cache; 

/*对query_cache加锁*/ 

  query_cache.lock(); 

/*获取hash*/ 

 queries = qc->get_queries(); 

  /* 遍历hash中的所有记录/

  for(uint i= 0; i < queries->records; i++)

  {

         /*根据索引号获取记录*/ 

   query_cache_block_raw = hash_element(queries, i); 

   query_cache_block = (Query_cache_block*)query_cache_block_raw; 

query_cache_query= query_cache_block->query(); 

   table->field[COLUMN_STATEMENT_ID]->store(i+1, 0); 

   /* 获取sql语句*/ 

   statement_text = (const char*)query_cache_query->query(); 

   statement_text_length = strlen(statement_text); 

/*当超出长度时需要截断…*/ 

   table->field[COLUMN_STATEMENT_TEXT]->store(  (char*)statement_text 

                                ,statement_text_length > MAX_STATEMENT_TEXT_LENGTH? 

MAX_STATEMENT_TEXT_LENGTH 

                                :statement_text_length 

                                , scs 

   ); 

   /* 获取该查询的key*/ 

   key = (const char*)query_cache_query_get_key(  query_cache_block_raw                          

                                                           ,&key_length  , 0 ); 

key_length =strlen(key+statement_text_length+1)-1; 

         /*数据库名是key的一部分，适当的偏移key指针可以得到数据库名*/