3 ms·

Or just having any long OLAP queries mixed into your OLTP workload. A readers-writer lock can often end up with tons of writers waiting on one last long read to

• manigandham 4y ago
  SQLite WAL mode means readers and writer don't block each other: https://www.sqlite.org/wal.html https://www.sqlite.org/wal.html Since it's SQLite, it's also trivial to just copy the database file as a snapshot for separate OLAP queries if necessary.
  • derefr 4y ago
    Not all OLAP queries are for reporting. Sometimes they drive OLTP processes — really complex, separate-statements but same-transaction equivalents to "INSERT/UPDATE/DELETE ... WHERE" queries. Of course, you can still drive those using a separate snapshot for the read side, to generate an ID set for a follow-up write on the business layer. But now you're doing CQRS — less trivial. You're not getting any of the ACID benefits of doing the OLAP and OLTP queries together in a single transaction; so your data model has to be designed for that (by e.g. having all tables be temporal tables.)