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7.5.4.3 Query Cache Configuration »
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7.5.4.2. Query Cache SELECT Options

Two query cache-related options may be specified in SELECT statements:

  • SQL_CACHE

    The query result is cached if it is cacheable and the value of the query_cache_type system variable is ON or DEMAND.

  • SQL_NO_CACHE

    The query result is not cached.

Examples: 

SELECT SQL_CACHE id, name FROM customer;
SELECT SQL_NO_CACHE id, name FROM customer;

User Comments

Posted by [name withheld] on August 24 2005 5:58pm[Delete] [Edit]

Note: Using SQL_NO_CACHE does not bypass the cache mechanism, so it is not a reliable way to time query speed. All it does is tell the server not to cache the results of the specific query you're sending.

If you've already executed the query without the option, some other time, that cached result will be fetched.

Posted by Oli Sennhauser on July 10 2006 1:36pm[Delete] [Edit]

I do not agree with the comment above because of 2 reasons:
1.) The hash is different when I have SELECT SQL_NO_CACHE * ... and SELECT * ... So the result will never match.
2.) See test sequence below:
mysql> select count(*) from City c1 join City c2 on c1.name = c2.name;

+----------+
| count(*) |
+----------+
|     4271 |
+----------+
1 row in set (7.98 sec)

mysql> select count(*) from City c1 join City c2 on c1.name = c2.name;
+----------+
| count(*) |
+----------+
|     4271 |
+----------+
1 row in set (0.00 sec)

mysql> select sql_no_cache count(*) from City c1 join City c2 on c1.name = c2.name;
+----------+
| count(*) |
+----------+
|     4271 |
+----------+
1 row in set (8.04 sec)

mysql> select sql_no_cache count(*) from City c1 join City c2 on c1.name = c2.name;
+----------+
| count(*) |
+----------+
|     4271 |
+----------+
1 row in set (8.46 sec)

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