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Dqlite – High-Availability SQLite

dqlite.io

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Re: Dqlite – High-Availability SQLite

#21

Post by hardwaresofton »

emmelaich wrote: post #6

I was going to ask what is the difference between this and rqlite, which also uses Raft. Found the answer on Reddit: > rqlite is a full RDBMS application, but dqlite is a library you must link with other code. It's like the difference between MySQL and libsqlite3.so. * https://www.reddit.com/r/golang/comments/8a8h8y/dqlite_distr...

There's one more big distinction, rqlite's replication is command based [0] where as dqlite is/was WAL frame-based -- so basically one ships the command and the other ships WAL frames. This distinction means that non-deterministic commands (ex. `RANDOM()`) will work differently.

It looks like dqlite's documentation has changed -- for some reason frames are no longer mentioned anywhere[2]. So maybe this isn't the case any more, but this was once the biggest differentiator for me.

[0]: https://github.com/rqlite/rqlite/#limitations

[1]: https://webcache.googleusercontent.com/search?q=cache:p1XBgh...

[2]: https://github.com/canonical/dqlite/commit/35ea7cd56e93a36c5...

Re: Dqlite – High-Availability SQLite

#25

Post by rlpb »

hardwaresofton wrote: post #21
emmelaich wrote: post #6

I was going to ask what is the difference between this and rqlite, which also uses Raft. Found the answer on Reddit: > rqlite is a full RDBMS application, but dqlite is a library you must link with other code. It's like the difference between MySQL and libsqlite3.so. * https://www.reddit.com/r/golang/comments/8a8h8y/dqlite_distr...

There's one more big distinction, rqlite's replication is command based [0] where as dqlite is/was WAL frame-based -- so basically one ships the command and the other ships WAL frames. This distinction means that non-deterministic commands (ex. `RANDOM()`) will work differently. It looks like dqlite's documentation has changed -- for some reason frames are no longer mentioned anywhere[2]. So maybe this isn't the case…

> dqlite is/was WAL frame-based...maybe this isn't the case any more

According to https://github.com/canonical/dqlite/blob/master/doc/faq.md this is still the case.

Re: Dqlite – High-Availability SQLite

#26

Post by hardwaresofton »

rlpb wrote: post #25
hardwaresofton wrote: post #21

Earlier quoted context omitted.

There's one more big distinction, rqlite's replication is command based [0] where as dqlite is/was WAL frame-based -- so basically one ships the command and the other ships WAL frames. This distinction means that non-deterministic commands (ex. `RANDOM()`) will work differently. It looks like dqlite's documentation has changed -- for some reason frames are no longer mentioned anywhere[2]. So maybe this isn't the case…

> dqlite is/was WAL frame-based...maybe this isn't the case any more According to https://github.com/canonical/dqlite/blob/master/doc/faq.md this is still the case.

Ahhhh thank you -- that information just got pushed into the FAQ -- I was thinking "surely they didn't just remove this information" but didn't look hard enough at all. Direct link:

https://github.com/canonical/dqlite/blob/master/doc/faq.md#h...

Re: Dqlite – High-Availability SQLite

#28

Post by dragonsh »

This is developed by LXD team for it's cluster. It's used by us in production as a part of LXD cluster. Initially there were some issues but now it can support thousands of nodes in a cluster easily in our regression tests.

It's good they made it as a separate project can be used independent of LXD containers.

Re: Dqlite – High-Availability SQLite

#29

Post by tyingq »

usgroup wrote: post #14

I'm not brimming with ideas of where this would be a good fit tbh. Is anyone using it or considering it for anything?

It's sort of like a SQL version of etcd, so maybe some of the use cases for etcd would be similar: https://github.com/etcd-io/etcd/blob/master/Documentation/pr...
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