How to avoid cache penetration problems using Memcached caching technology in PHP?

With the popularity of Web applications and the increasing amount of data, caching technology has become an indispensable part of Web applications. As an efficient distributed caching system, Memcached has been widely used in the Internet field. However, when using Memcached caching technology, you may encounter some problems, such as cache penetration problems. So, how to avoid cache penetration problems when using Memcached caching technology in PHP? Here are some solutions for you.

What is the cache penetration problem?

The cache penetration problem refers to querying data that does not exist when using cache technology, resulting in the need to search in the database for each query, which puts a lot of pressure on the database. In this case, the cache not only fails to play a role, but also becomes a bottleneck, affecting the performance and stability of the system. Usually, cache penetration problems are caused by malicious attacks or system code problems.

How to use PHP-Memcached to avoid cache penetration problems?

1. Interface parameter verification

When performing cache query, we need to verify the parameters passed into the interface. For example, if we hope that the data ID we query must be a legal number, then we need to perform type verification on the incoming ID. If it is not a number, it will be returned directly. This can effectively avoid cache penetration problems caused by malicious attacks or system code problems.

2. Data preheating

Another solution is to perform data preheating. That is, when the system starts, all possible data is preloaded into the cache. In this way, non-existence will not occur when querying data. Of course, this method is not suitable for very large amounts of data because it consumes a lot of system resources.

3. BloomFilter filter

The more advanced technology is to use the BloomFilter filter, which can hash the possible data and interface parameters in advance and calculate the The resulting hash value is stored in a bit array. When the interface parameters are passed in, the hash value can be directly calculated for judgment. If the value does not exist in the bit array, it will be returned directly. This method can well avoid cache penetration problems and consumes very little system resources.

4. Set TTL time

The last solution is to set the expiration time (TTL) of cached data. When querying data that does not exist, we can set a shorter TTL time for the data and make a judgment during the query. If the data does not exist, it will be returned directly. This method can effectively avoid cache penetration problems and consumes very little system resources.

Conclusion

To sum up, the cache penetration problem is a very common cache technology problem, which will have a great impact on the performance and stability of the system. When using PHP-Memcached caching technology, we need to pay attention to verifying interface parameters, preheating data, using BloomFilter filters and setting TTL time to avoid cache penetration problems. At the same time, we need to choose the appropriate solution according to the specific situation to ensure the performance and stability of the system.

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