Re: ZODB storage for cassandra
Jim Fulton <[email protected]>
| Newsgroups | gmane.comp.web.zope.zodb |
|---|---|
| Message-ID | <CAPDm-FhOk8C=987SAR21K3u8-c1Jf0sTDL-RFBgVxCSR2X5o0A@mail.gmail.com> |
On Mon, May 15, 2017 at 7:12 AM, Ramon Navarro Bosch <[email protected]> wrote: > We are starting to use https://www.cockroachlabs.com , I really like the > aproach, have you tried Jim ? > Nope. They certainly make some big promises. Something that makes it hard to compare databases is that they don't always mean the same thing by "consistency". In NoSQL databases "consistency" means that different copies of a single data record across distributed nodes are consistent. In traditional, non-distributed, transactional databases, consistency refers to a collection of related records being logically consistent. It's worth noting that ZODB is even less scalable than relational databases due to the way it maintains cache consistency. ZODB database caches are essentially database replicas. An object cache is maintained in a point-in-time consistent state. To achieve this, the database is essentially versioned. Each transaction has an id and ids are increasing over time. Assigning these ids requires a global lock. So even writes to unrelated data must be serialized. Jim -- Jim Fulton http://jimfulton.info -- You received this message because you are subscribed to the Google Groups "zodb" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.