Size of Query Cache Has Impact on Performance

In general, size impacts the performance. The size of My SQL query cache will affect My SQL Performance features. If the server has free RAM, setting the size of My SQL Query cache reduces cache prunes. Thereby it increases the performance. A My SQL query cache size of 200 MB tends to be larger. It is important to start with small size. Thereby it is valuable to consider the maintenance of high ratio of query cache hits and also low amount of query cache. The largest size of query cache leads to the performance degradation. This finally results in issues with cache. Queries accountable for cache removes the lock on My SQL query cache. In addition to this, operations like insert, update, delete or other modifications causes changes in the query cache. As a result, if the size of query cache goes larger, system takes more time to clear the locks. For instance, if the size of My SQL query cache size is set to 4 GB, the query may result as waiting for query cache lock.

Query Cache – Performance:

Instead of letting the database to execute the queries again and again, allowing the cache to resolve the queries is better. It is always safe to enable query cache, if the size goes above 50%. Due to the changes in My SQL set-ups, hardware specifications and database may differ among different facts like demand, query types and etc. Use always 200 MB as a pre-made suggestion. A My SQL’s cache size of 200 MB will vary based on server. Therefore, it becomes vital for investigation and this is to set the logging time of query as 1 second.

Cache with Average Speed Rate:

Query caching has greater impact towards the performance improvements. When you start to change the query cache size, check whether you adjust query cache limit as lesser than 1MB. Enable to fill up the cache at average speed rate, because, if you allow for the faster creation, it may lead to cache prunes. Have a glance at query cache tuning parameter so as to combat cache fragmentation. In most cases, you may feel difficult to store all cacheable queries in the query cache, but you can make use of it.

Set of Queries:

Qcache-free-memory:

It frees out the memory for new queries to be cached.

Qcache-inserts:

It tells the number of queries to be cached from the time when My SQL started.

Qcache-queries-in-cache:

It shows the queries present in cache.

Impact on Performance Improvements:

Mysql query cache is one of the most suitable features in My SQL. It is important to analyze the working mechanism of My SQL. It has the role in causing performance improvements. The My SQL query cache is a global one among the sessions.It is important to have unique spaces. It is important to know the environment in order to enable My SQL query cache and to check what the query cache size is. Setting the query-cache-type to zero eliminate the query cache mutex, as the query cache is difficult to enable during run-time.
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Bhawani Singh
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