Invalidating query cache entries table mysql

Invalidating query cache entries table mysql

At this time the

You need an efficient and reliable cache in order to achieve the desired result. If you do not have a lot of repeated queries, this can happen even after the cache is warmed up.

That is the server hasn't had a chance to fill the cache with result sets. For example, suppose we need to calculate the total count of items sold. This does not, however, offer very much improvement for keys which are not accessed very frequently. It is important to only cache things you know you will need again. For example, the position is and I want to analyze the previous five events.

The query cache

In order to make the miss path less expensive, use a layered approach to your caching. The server is seeing queries it hasn't seen before. This forces one query to do the computation while others wait for the result. This happens when multiple requests need data for the same key, but the key recently expired.

This method does not usually work well when database tables may be updated or when rows may be deleted. We are having issues with inconsistencies over time. External cache Memcached In order to eliminate the unpredictable nature of the the query cache, external caches like Memcached are usually employed.

One advantage of summary tables is that they are persistent unlike the query cache or Memcached. The query cache is not warm yet.

One advantage of

When this happens, the application attempts to get the cached value and fails. You lose all cached results, so run these lines during off-peak hours. The recording and slides for the webinar are available here. The summary table always exists, and should be fast to access, since it can be indexed appropriately for your queries. There are also probabilistic methods to enqueue items to be rebuilt with some increasing probability as the request time approaches the expiration time.

At this time, the application must compute the results, then place them into the cache. Regarding data consistency between the master and slave, you need to use row-based replication.

Ideally, the summary tables can be updated with only the information that changed since they were last populated. The other big problem with the query cache is that it is protected by a single mutex.

With this type of source data, one does not expect to see very many if any updates to the data once it has been collected. When talking about cache, the miss path is at least as important as the hit one. This improves the response time by avoiding the work of the query. Using less computing resources, particularly in the cloud, results in decreased overall operational costs, so caches provide real value by avoiding using those resources. If you perform hundreds of queries, fragmentation will come about rather quickly.

This recalculation may be very expensive. Cache data in the form that it makes most sense to your application. That is, the keys which are frequently accessed, or those that are expensive to recompute. This results in unpredictable and therefore, undesirable, performance.