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> MySQL is being used from top-traffic websites like Facebook and Twitter, to high traffic websites like GitHub and Basecamp and almost every PHP installation o

> MySQL is being used from top-traffic websites like Facebook and Twitter, to high traffic websites like GitHub and Basecamp and almost every PHP installation out there. Is it just me, or does this seem rather misleading? My understanding is that they can use MySQL because they've carefully designed their architectures to direct most hits to caches or Memcache/Redis, which minimizes the load on the database.

ralusek 10y ago
How is that misleading? Using RDBMS as your primary data store is the decision that people reading this are going to benefit from. When it comes time to cache and optimize for things like search, that's when you use the additional technologies. It's a huge mistake to think that companies that are using Redis/ElasticSearch/MapReduce are doing so to cover up for the wrong decision they made of going with an RDBMS. The RDBMS is their source of truth, everything else is just an indexing mechanism.
- user5994461 10y ago
  The RDBMS doesn't have to be the source of truth. Other databases can do that just fine.
smsm42 10y ago
It at least sounds misleading. Saying "Tool X is used at company Y which serves $tons_of_traffic" is not the same as saying "tool X is directly involved in serving $tons_of_traffic for company Y and replacing it with tool X' would not allow to do the same but would result in much worse results". But on a cursory reading, the former reads just like the latter. For almost all really high-traffic sites, and many not-facebook-scale-but-also-high-traffic sites, there are multiple layers of content generation and caching. Nobody serves Facebook-scale content directly from MySQL (or any other backend DB) to the wide web, that'd be insane. So when talking about backend performance, one always has to remember the layer involved and look for what happens in those layers.

ralusek 10y ago

How is that misleading? Using RDBMS as your primary data store is the decision that people reading this are going to benefit from. When it comes time to cache and optimize for things like search, that's when you use the additional technologies. It's a huge mistake to think that companies that are using Redis/ElasticSearch/MapReduce are doing so to cover up for the wrong decision they made of going with an RDBMS. The RDBMS is their source of truth, everything else is just an indexing mechanism.

user5994461 10y ago
The RDBMS doesn't have to be the source of truth. Other databases can do that just fine.

smsm42 10y ago

It at least sounds misleading. Saying "Tool X is used at company Y which serves $tons_of_traffic" is not the same as saying "tool X is directly involved in serving $tons_of_traffic for company Y and replacing it with tool X' would not allow to do the same but would result in much worse results". But on a cursory reading, the former reads just like the latter. For almost all really high-traffic sites, and many not-facebook-scale-but-also-high-traffic sites, there are multiple layers of content generation and caching. Nobody serves Facebook-scale content directly from MySQL (or any other backend DB) to the wide web, that'd be insane. So when talking about backend performance, one always has to remember the layer involved and look for what happens in those layers.