December 5, 2012 at 12:27 pm
Hi everyone,
I've done a lot of sql programming and administration over the years (10+). However, i've worked mostly for start-ups and have no experience with multi-terabyte databases. On a recent interview for a SQL development position, i pretty much nailed all the questions they threw at me but was told later that my lack of experience with VLDBs caused me to be cut from consideration. I know there are many administration problems/considerations that appear with large databases that do not with smaller ones, but i'm wondering what the differences are for the developer. Most jobs i come across these days require experience with VLDBs and i am wondering what i can do/study/know to have a shot at such jobs without direct experience in the big db world. To put it shortly, what challenges does a sql programmer face with VLDBs that he would not with smaller dbs?
Many thanks in advance for your help.
-bird
December 5, 2012 at 12:31 pm
bagofbirds-767347 (12/5/2012)
To put it shortly, what challenges does a sql programmer face with VLDBs that he would not with smaller dbs?
Performance.
Everything's fast on few hundred rows. With a small database a developer can write any garbage query, ignore indexes and it'll still work fairly well. When you're dealing with millions of rows, the same does not apply.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
December 5, 2012 at 1:01 pm
gotcha. so indexes and general performance tuning is an issue. I have done a good amount of performance tuning in my day. When tables grow over a million rows say, queries and indexes need to be adjusted. Query plans need to be examined and i know basically how to do this, how to look out for table scans, apply indexes, examine i/o reads and writes. Though i guess what you are saying is that performance tuning is much more complex in the VLDB world? Would you say then, that the ability to expertly examine query plans and have an expert (though perhaps only academic) knowledge of perf tuning would help me out here? i'd like to be able to say to my interviewer that i at least have an academic knowledge of what is different when dealing with large dbs.
Thanks for your input. are there other issues besides perf tuning anyone can think of?
thanks again
-bird.
December 5, 2012 at 1:32 pm
Maintenance and backups are a challenge.
Table partitioning can be a consideration.
CEWII
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