![]() Some database vendors consider them effectively the same isolation level because the anomalies associated to other common non-serializable isolation levels aren't typically present in most MVCC implementations, but there's a lot more complexity here than you are acknowledging. So in your case, MVCC is what you're talking about, which is not the same level of consistency guarantee as serializable, rather it is based on snapshot isolation. Doing this on one server is much easier than doing this across a cluster of servers. ![]() You can process queries in parallel and still have a serializable result, because of transaction coordination. Databases have special concurrency control requirements in order to create hard guarantees on database consistency. "serialized" here doesn't really mean processed in serial, it means "serializable" in the context of database information theory. I'd rather just accept the fundamental truth of the hardware/OS and have the least amount of overhead possible when engaging with it. After a certain point, this is kinda like trying to beat basic information theory with ever-more-complex compression schemes. At the end of the day, you still have to go to disk on writes, and this must be serialized against reads for basic consistency reasons. I am not aware of any hosted SQL technology which is capable of magically interleaving large aggregate queries with live transactions and not having one or both impacted in some way. They go out to all of the SQLite databases, make a copy and then run analysis in another process (or on another machine). We have some telemetry services which operate in this fashion. If we wanted to run an aggregate that could potentially impact live transactions, we would just copy the SQLite db to another server and perform the analysis there. I would argue it is a bad practice in general to mix OLTP and OLAP workloads on a single database instance, regardless of the specific technology involved. ![]() We aren't running any reports on our databases like this. We support hundreds of simultaneous users in production with 1-10 megs of business state tracked per user in a single SQLite database. Something about it living in the same process as your business application seems to help a lot. SQLite has the lowest access latency that I am aware of. I do not think you can persist a row to disk faster with any other traditional SQL technology. If at this point you are still finding that SQLite is not as fast or faster than SQL Server, MySQL, et.al., then I would be very surprised. Execute one time against a fresh DB: PRAGMA journal_mode=WAL Trying to use the one connection per query approach with SQLite is going to end very badly.Ģ. SQLite operates in serialized mode by default, so the only time you need to lock is when you are trying to obtain the LastInsertRowId or perform explicit transactions across multiple rows. Only use a single connection for all access. If you are struggling to beat the "one query per second" meme, try the following 2 things:ġ.
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