Variable not loading right away

Bug reports
1

I have quite a comlicated SQL including internal variables:

              @MSR_rank := IF(@current_to_place = g1.to_place, @MSR_rank + 1, 1) AS MSR_rank,
              @current_to_place := g1.to_place

which is included in left join (select…)

The problem is that when the chart is loaded, it seems to ignore the variable. But after one (sometimes 2-3) reloads of the page, it catches up and displays properly.

Does anybody have any idea why this unexpected behaviour? Is it a bug?

2

Hi @ivobrabec
Post “Diagnostic Info” from Admin > Troubleshooting, and which database you are querying.
Could it be that you’re using multiple statements? That’s currently no supported very well:
https://github.com/metabase/metabase/issues/4050 - upvote by clicking :+1: on the first post

3

Yes, definitely I have multiple statements in the SQL (the SQL is selecting top X results from group by and counting the reminder as ‘other’).
Nevertheless, evidently Metabase is able to handle it, I just don’t understand why I need to reload before it kicks in.
The database info is:
{
“browser-info”: {
“language”: “en-US”,
“platform”: “MacIntel”,
“userAgent”: “Mozilla/5.0 (Macintosh; Intel Mac OS X 11_2_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.82 Safari/537.36”,
“vendor”: “Google Inc.”
},
“system-info”: {
“file.encoding”: “UTF-8”,
“java.runtime.name”: “OpenJDK Runtime Environment”,
“java.runtime.version”: “11.0.10+9”,
“java.vendor”: “AdoptOpenJDK”,
“java.vendor.url”: “https://adoptopenjdk.net/”,
“java.version”: “11.0.10”,
“java.vm.name”: “OpenJDK 64-Bit Server VM”,
“java.vm.version”: “11.0.10+9”,
“os.name”: “Linux”,
“os.version”: “4.15.0-135-generic”,
“user.language”: “en”,
“user.timezone”: “GMT”
},
“metabase-info”: {
“databases”: [
“mysql”
],
“hosting-env”: “unknown”,
“application-database”: “mysql”,
“application-database-details”: {
“database”: {
“name”: “MySQL”,
“version”: “5.7.33”
},
“jdbc-driver”: {
“name”: “MariaDB Connector/J”,
“version”: “2.6.2”
}
},
“run-mode”: “prod”,
“version”: {
“date”: “2021-03-17”,
“tag”: “v0.38.2”,
“branch”: “release-x.38.x”,
“hash”: “91f0ed6”
},
“settings”: {
“report-timezone”: “Europe/Brussels”
}
}
}

4

@ivobrabec There are many different ways to write a query, but it doesn’t sound like you are using multiple statements.
Try doing EXPLAIN ANALYZE or enable debugging logs on MySQL to see why it behaves like that.

5

Thanks again, unfortunately my database is not upgrade to run analyze and explain does not give me much info. But the issue is that when I run the sql on mysql directly, this issue does not happen. Its metabase only which presents different results in appx. 50% cases. Is there a way to debug such behaviour?

6

@ivobrabec Not without debugging what the database does, since Metabase sends the query to the database. Otherwise create a function or view on the database and just call that from Metabase.

7

OK thanks. Just to clarify, I cannot use a mysql procedure in metabase, right? Since I cannot use multiple statements in one chart, correct? (building the SQL with a function is a challenge…)

8

@ivobrabec You can use (call) a procedure in Metabase, but you cannot create and call, since that would be multiple statements.