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#datomic
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2020-07-27
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Sven13:07:17

Is it possible to preload multiple databases after instance restart or speed up the initial d/connect? I’d like to deploy ions often but every deployment results in the initial d/connect to a non preloaded db taking 10+ seconds.

Joe Lane13:07:33

@sl What kind of topology are you using?

Sven13:07:12

@joe.lane solo for dev and testing and production for qa and live

Joe Lane13:07:15

• Is it the same production topology for QA and Live? • How do you know the problem the d/connect time is taking a long time? • Are you sure it's not because of lambda coldstart? • Have you considered using HTTP DIrect?

Joe Lane14:07:01

@sl I'm not sure how you're measuring the time, but the first thing I would look at is switching to Http Direct if you aren't already using it.

Sven14:07:16

1) yes. Though the issue is way more pronounced on solo. 3) lambda cold starts occasionally contribute to the issue but I run lambda warmers to help mitigate this 4) I am using appsync so I have to invoke lambdas

Joe Lane14:07:29

3) I think that lambdas are rebuilt on redeploy so I'm not sure your warmers would be able to help 4) Doesn't appsync also support an http proxy?

Sven14:07:42

hmmm, I have somehow completely missed ions with HTTP direct. I’ll do some testing on production topology. Thanks for that tip! 2) as of d/connect taking a long time - when I manually reboot the solo topology instance and after restart connect to that system from my laptop (bypassing the lambda function altogether) then the first connect +query/transaction takes a long time.

David Pham14:07:59

With dev-local, what are the limitations about storage, number of transactors and readers?

stuarthalloway16:07:41

Hi David. dev-local is in process, so there are no transactors. Memory usage is described at https://docs.datomic.com/cloud/dev-local.html#limitations.

David Pham05:07:25

Thanks Stuart!

kschltz15:07:38

Hi there, I've heard rumours about datomic cloud support for cross db queries, do you guys know something about this? Any reading material on the subject is more than welcome

Joe Lane16:07:23

Cross DB queries in cloud refers to the same db at two different points on it's timeline, not two different databases across timeline's.

kschltz17:07:37

I see, given that I have db-A and db-B, isn't there any built-in features to support simultaneous queries in both bases?

kschltz21:07:31

Other thing that isn't very clear to me regarding datomic cloud. Suppose I have a production topology with several dbs, would the write ops interfere with one another among those databases or are they served by different transactors?

Joe Lane23:07:48

@schultzkaue Different transactors. They would not compete for resources in the way you described.

kschltz23:07:58

Great, thanks

stuarthalloway16:07:52

I would just add that you can increase the number of processes in the primary compute group if you have many databases: https://docs.datomic.com/cloud/operation/scaling.html#database-scaling

😄 6
kschltz14:07:14

That would be a perfect fit