Redshift schemas and tables disappearing in the source panel

1

I have a MySQL (DB-06) and Redshift database sources., both with a lot of tables.

After a certain time of using dremio (creating virtual tables and reflections from Redshift) the source browser always start showing 0 item from Redshift and cannot run the previously created queries any more. If I login to Redshift with another client the tables are there. Deleting and recreating the redshift connection solves the problem but obviously not a great workaround.

Any idea how to solve this? This happens only with redshift source and not with mysql.

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2

I have this reproduced in an internal environment right now (fortunately), can you tell us more about where you have Dremio running?

3

I’m on the latest community edition on windows with 16gb ram. I m trying to create a reflection from a single redshift table (select * from …) with 30millions of rows and 10 columns.

I have this issue sometimes after 10 minutes of start creating the reflection sometimes after 2 or 3 hours.

4

Hi @koszti,

There looks to be an issue where the Redshift driver doesn’t validate that connections it retrieves from its connection pool are still valid properly. So I believe the problem is that Dremio gets a stale connection to Redshift, then fails to retrieve the list of tables from Redshift when this happens.

5

I’ve also experienced this issue earlier today after having Dremio connected to a Redshift cluster for roughly 10 days. I was able to fix it by changing the Redshift JDBC connection string to something bogus, then changing it back. It does look like Dremio was having issues with stale connections in its connection pool. Is there a known fix for this?

6

Hi @mclennon and @koszti,

We have a fix for this problem now. We updated the Redshift JDBC driver shipped with Dremio to resolve issues with connections being expired when pulled from a connection pool.

It will be available in the next release.

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7

Hi guys. I’m using Dremio 2.0.5-201806021755080191-767cfb5 and I am still facing this problem. A few hours after I create a Redshift source connection, the schemas and tables disappear.

@jduong told that the team updated the Redshift JDBC driver shipped with Dremio. Does this version contain this driver? If yes, can somebody help me to understand why I am still getting this error?

Thank you guys

8

Hi @Paulo_Vasconcellos,

Dremio 2.0.5 does not include the updated Redshift driver. The 3.0.1 release now available does include the updated driver.

9

Thank you @jduong! I’ll update it

10

I have installed Dremio 3.3.1 in my local system but still Redshift datasource is not showing up any schema.Please see below screenshot.

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11

@rohit9512

There could be an error in server.log, can you please look into server.log and see what is going on? If not able to figure out, send us the server.log, remove the source, add it again and send us the server.log right after that