xtdb 2022-08-27 | Slack Archive

kokonut13:08:42

Has anyone seen this message? I see it both at lein run and lein install. The app still runs so I think this isn't a big issue but I want to figure this out. Especially when lein install, the command line got stuck, so I have to break it manually. WARN xtdb.cache - Could not open ConcurrentHashMap.table field - falling back to LRU caching. Use --add-opens java.base/java.util.concurrent=ALL-UNNAMED` to use the second-chance cache. INFO xtdb.tx - Started tx-ingester`

lispyclouds14:08:01

its from: https://github.com/xtdb/xtdb/issues/1462

🙏 1

kokonut14:08:34

Interesting, because I am using jdk-11.

lispyclouds14:08:14

hmm, shouldn't show up then. not sure why. totally sure its not jdk 16+ somehow?

kokonut14:08:11

Hmm, could this be affirmative? `$ java -version openjdk version "11.0.11" 2021-04-20 OpenJDK Runtime Environment AdoptOpenJDK-11.0.11+9 (build 11.0.11+9) OpenJDK 64-Bit Server VM AdoptOpenJDK-11.0.11+9 (build 11.0.11+9, mixed mode)`

lispyclouds14:08:02

could be, or your lein could be picking up a different jdk somehow. could try running (System/getProperty "java.version") in the lein repl

kokonut14:08:30

Ah, it returns "18.0.2.1".

kokonut14:08:52

I don't know why this happens though.

lispyclouds14:08:11

yeah lein is probably picking up a different JAVA_HOME maybe?

lispyclouds14:08:36

check what $JAVA_HOME is set to?

lispyclouds14:08:46

why its a different java version can have a lot of reasons and mostly its local machine things, not so straightforward to locate unfortunately 😕

kokonut14:08:46

Can #JAVA_HOME be shown on Repl?

lispyclouds14:08:46

its something that has already been set before lein starts

lispyclouds14:08:01

its a shell variable

kokonut14:08:54

I believe it isn't set up on my home folder

lispyclouds14:08:59

(System/getenv "JAVA_HOME") reads it from the repl but no guarantees its there

lispyclouds14:08:14

yeah at this point is pretty much a problem specific to your machine, try narrowing it down why java -version is 11 when theres a jdk 18 on your system too

kokonut14:08:04

Yep, I got it. Let me do the research and will share the result here. Thanks a lot for help!

➕ 1

tbrooke15:08:09

This may be off base but I have been reading about CRDTs and from what I understand it seems to be where XTDB is heading - Here is a CRDT Explainer https://youtu.be/gZP2VUmH05A. Just curious about the overlap if there is any

refset16:08:14

There's definitely overlap 🙂 Bitemporal modelling alone certainly can't "solve" all the hard problems in this space, but it's certainly a widely used primitive for making sense of time in a distributed world. Note that you could, if desired, already encode 'virtual clocks' into regular valid time timestamps, e.g. https://github.com/xtdb/xtdb/issues/895#issuecomment-636041476 I know Materialize, via Differential Dataflow (the underlying engine) has some kind of internal support for generalized "multitemporal" timestamps, which probably gets a bit closer (there are better links than this out there, I'm sure: https://github.com/MaterializeInc/materialize/issues/1309). DD was also used within https://github.com/sixthnormal/clj-3df and some CRDT-in-Datalog examples were experimented with at the time: https://github.com/sixthnormal/clj-3df/blob/7dfb89a438f9fb1a3c5d0d356f05acf3f9c51177/examples/rga.clj

2022-08-27

Channels