NOT IN (SELECT ...) and NOT EXISTS (SELECT .. WHERE correlation..) are "Anti Semi Joins". That is, recognised set based operations
WHERE NOT (MyColumn = 1) is a filter that requires all rows to be looked at
For more info, see:
Craig Freedman's "Introduction to Joins"
Wikipedia "Relational a...
I have to recreate this table to test anything anyway. Our old table didn't copy the full PK...I don't even know how this worked. It's an incomplete copy of another table on another DB
Without the full PK there's no way to make sure I get 100% of and only the correct rows best I can tell
We made it. It was part of an access database. It's a small chunk of a largeish table. Since the original data isn't ever updated through the app and performance is a big issue I'm keeping the partial table for now
it's kind of a stupid use case but it's what we've been doing
Alright. I am going to run along and get connected to an environment, just wanted to pop in. I wish you the best in that "when to leave" decision process, @gbn :-)
Hm. I have a 3,000,000 row table and I only need a specific subset of data. Do I A) make a select statement that only includes relevant data or B) select * the whole table and process the entire result set as a file RBAR?
@BenBrocka A developer at one of my clients was named Anurag, shortened to Anu. Once he left and we looked closely at the quality of his work, we coined "anu-rysm" as the inhouse catch phrase for dodgy code.
@BenBrocka Also, as critical as I can be of crud when I see it, I'm acutely aware that it's much easier to point out a better way of doing something than it is to get it right first time.
Oh, that makes more sense then. Refactoring and doing things right isn't really THAT hard. They just taped something together and forgot about it about 500 times too often
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My company's still at the level of "if you publish that a competitor might gain an advantage" for something like a better development process, or a tuning technique.
Have tried persuading the client that something smaller with SSD, or local SSD would be better (its for a dev/test hyper-v cluster) but they won't trust SSD yet sigh
I have a query that is taking a long time in the middle of a transaction. When I get the wait_type of the process it is PAGEIOLATCH_SH. What does this wait type mean and how can this be resolved?
NOT IN (SELECT ...) and NOT EXISTS (SELECT .. WHERE correlation..) are "Anti Semi Joins". That is, recognised set based operations
WHERE NOT (MyColumn = 1) is a filter that requires all rows to be looked at
For more info, see:
Craig Freedman's "Introduction to Joins"
Wikipedia "Relational a...
Edit this post as you feel is appropriate.
Blog Post Requirements
Peer review: Post must be reviewed and approved by at least 2 other dba.se editors.
Rep/badge requirements (?):
1,000 rep
On topic: Anything on topic for the main site.
I have a query that is taking a long time in the middle of a transaction. When I get the wait_type of the process it is PAGEIOLATCH_SH. What does this wait type mean and how can this be resolved?
