March 12, 2019 at 3:50 pm
Just out of curiosity how big a whiff would you consider not knowing the difference between a clustered and non-clustered index in SQL Sever?
We're hiring for an ETL "BI" guy/gal --- light DBA duties (like backups, monitoring) -- okay maybe not so light, but it would be nice.
I understand an ETL guru not necessarily need to be an expert in SQL server. That said ... uh ... turning indexes on and off during ETL may be important. "Reading" and tuning queries fast enough to be imported into OLAP cubes or wherever is important.
In your opinion, --- the difference between a clustered and non-clustered index in SQL Sever (I would have accepted that a clustered index is a physical ordering of the database).
If an interview candidate didn't know that, would you consider that junior level? Still potentially mid-level? Obviously they are not expert level with that response.
Curious if I'm making too much out of it.
March 13, 2019 at 2:30 am
well how important turning indexes on / off highly depends on your architecture, if you process data in your DWH and Reporting is done somewhere else, you usually don't have many indexes you'd want to keep around anyways. But you should definitely know how to work with indexes because tuning will require knowing them rather well so I'd say junior level tops.
March 13, 2019 at 7:22 am
Funny enough, that's one of my phone screen questions. I'd say anyone that has to do more than consume data from SQL Server really has to know this. It's one thing if they're just moving data around. However, they're not simply going to disable/enable indexes, there's a good chance that they'll occasionally need to drop & recreate them. Not knowing what a clustered index is and the implications it has on non-clustered indexes is a sign of a junior person. However, that's my opinion, not hard fact.
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March 14, 2019 at 10:46 am
peter_parker - Tuesday, March 12, 2019 3:50 PMJust out of curiosity how big a whiff would you consider not knowing the difference between a clustered and non-clustered index in SQL Sever?We're hiring for an ETL "BI" guy/gal --- light DBA duties (like backups, monitoring) -- okay maybe not so light, but it would be nice.
I understand an ETL guru not necessarily need to be an expert in SQL server. That said ... uh ... turning indexes on and off during ETL may be important. "Reading" and tuning queries fast enough to be imported into OLAP cubes or wherever is important.
In your opinion, --- the difference between a clustered and non-clustered index in SQL Sever (I would have accepted that a clustered index is a physical ordering of the database).
If an interview candidate didn't know that, would you consider that junior level? Still potentially mid-level? Obviously they are not expert level with that response.
Curious if I'm making too much out of it.
It depends.
If it was any candidate that was interviewing for any kind of DBA position, then that would be a show-stopper.
If it was a developer position, that would be a show-stopper if they were applying for anything higher than an entry level position. That being said, I'm betting that I could ask that question of the developers here and I might get 2 or 3 right answers!
A BI position is probably the same a developer, if they have done this kind of work, and have no real idea of the meaning of a clustered or non-clustered index, then they probably have not done anything too terribly difficult.
Michael L John
If you assassinate a DBA, would you pull a trigger?
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March 14, 2019 at 10:18 pm
peter_parker - Tuesday, March 12, 2019 3:50 PMJust out of curiosity how big a whiff would you consider not knowing the difference between a clustered and non-clustered index in SQL Sever?We're hiring for an ETL "BI" guy/gal --- light DBA duties (like backups, monitoring) -- okay maybe not so light, but it would be nice.
I understand an ETL guru not necessarily need to be an expert in SQL server. That said ... uh ... turning indexes on and off during ETL may be important. "Reading" and tuning queries fast enough to be imported into OLAP cubes or wherever is important.
In your opinion, --- the difference between a clustered and non-clustered index in SQL Sever (I would have accepted that a clustered index is a physical ordering of the database).
If an interview candidate didn't know that, would you consider that junior level? Still potentially mid-level? Obviously they are not expert level with that response.
Curious if I'm making too much out of it.
I'm sure that there are many folks out there that will disagree with me but for people doing ETL (ELT, LET, or whatever you want to call it anymore), I personally consider an in depth understanding of indexes and indexing (along with "Minimal Logging" and what happens when you "turn an index on" (which isn't actually that simple) to be a critical skill. People that don't know those things don't even qualify as a "junior" in the area of ETL, IMHO.
--Jeff Moden
Change is inevitable... Change for the better is not.
March 15, 2019 at 7:40 am
Jeff Moden - Thursday, March 14, 2019 10:18 PMI'm sure that there are many folks out there that will disagree with me but for people doing ETL (ELT, LET, or whatever you want to call it anymore) [...]
GIGO? 😀
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March 17, 2019 at 5:03 pm
jonathan.crawford - Friday, March 15, 2019 7:40 AMJeff Moden - Thursday, March 14, 2019 10:18 PMI'm sure that there are many folks out there that will disagree with me but for people doing ETL (ELT, LET, or whatever you want to call it anymore) [...]
GIGO? 😀
Perfect! 😀 Same number of characters as "Crap". :D:D:D
--Jeff Moden
Change is inevitable... Change for the better is not.
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