March 16, 2014 at 7:30 pm
andrew gothard (3/16/2014)
GilaMonster (3/16/2014)
I have two clients where I'm writing up a performance report which includes an entire section on their use of NoLock. Going to be an interesting weekPHB "I've decided to make NOLOCK a standard, we're going to put it in every query." "No we're not". "I'm the Boss, I'm playing the boss card, we are". "Nope, not going to happen" <Hissy>, "we need the program to be fast!". "And inaccurate?", "YES, IF Needs be, we need to be Agile". "What part of the Agile Manifesto recommends inaccurate results, I missed that bit ... "
Funnily enough, he was actually a lovely guy.
I wonder why these people suggest to use NOLOCK on every query but won't ever suggest to use read uncommited isolation level. That only shows how little they know about this hint and its effects.
March 17, 2014 at 5:32 am
Jeff Moden (3/16/2014)
andrew gothard (3/15/2014)
GilaMonster (3/15/2014)
Wow, the things you learn around here.If you check index fragmentation, enable locked pages and enable (but don't configure) resource governor, SQL will magically start to use less memory
http://www.sqlservercentral.com/Forums/FindPost1551457.aspx
and the max memory that a process installed on 32-bit Windows can use is 32 GB. http://www.sqlservercentral.com/Forums/FindPost1551464.aspx
Don't recognise the name, but that is actually about the quality of "advice" I get from some of our vendors "SQL Experts". I'll post some of the bewilderingly clueless crap - including the "Well you've probably not heard of him, but I'm a member of Brent Ozar's group and he says .." "You're a member of Brent's GROUP? What do you mean by that, you subscribe to his newsletter, what have you run sp_blitz, sp_blitzindex, sp_AskBrent - I've run all of those and a shedload of other scripts, send me the output, we can go through it". "Er, I've not got the links" ... <Growl> "So what are you running and what's your output". Can I get back to you ...
My all-time "favorite" for bad vendor advice hit me right in the kisser when I started a new job more than a decade ago. When "gearing" up for what their "standards" might be, they told me that they had just spent 6 months and a god awful number of over-time manhours fixing all of their biggest performance problems based on a vendor's "expert" recommendation (4 of their staff concurred on the recommendation). The recommendation?
"Replace all cursors with Temp Tables/While Loops and add WITH(NOLOCK) to all queries." :blink::pinch::sick:
That's quite a piece of...er uh..."advice".
March 17, 2014 at 5:57 am
andrew gothard (3/16/2014)
GilaMonster (3/16/2014)
I have two clients where I'm writing up a performance report which includes an entire section on their use of NoLock. Going to be an interesting weekPHB "I've decided to make NOLOCK a standard, we're going to put it in every query." "No we're not". "I'm the Boss, I'm playing the boss card, we are". "Nope, not going to happen" <Hissy>, "we need the program to be fast!". "And inaccurate?", "YES, IF Needs be, we need to be Agile". "What part of the Agile Manifesto recommends inaccurate results, I missed that bit ... "
Funnily enough, he was actually a lovely guy.
I just had a client tell me they are perfectly fine with inaccurate results. Every query in the databases employs the nolock hint. Yes - every query.
When asking them if it was ok if they over/undercharged a client or if their financials were wrong - they said it's ok because somebody will probably just rerun them anyway.
Jason...AKA CirqueDeSQLeil
_______________________________________________
I have given a name to my pain...MCM SQL Server, MVP
SQL RNNR
Posting Performance Based Questions - Gail Shaw[/url]
Learn Extended Events
March 17, 2014 at 6:45 am
SQLRNNR (3/17/2014)
andrew gothard (3/16/2014)
GilaMonster (3/16/2014)
I have two clients where I'm writing up a performance report which includes an entire section on their use of NoLock. Going to be an interesting weekPHB "I've decided to make NOLOCK a standard, we're going to put it in every query." "No we're not". "I'm the Boss, I'm playing the boss card, we are". "Nope, not going to happen" <Hissy>, "we need the program to be fast!". "And inaccurate?", "YES, IF Needs be, we need to be Agile". "What part of the Agile Manifesto recommends inaccurate results, I missed that bit ... "
Funnily enough, he was actually a lovely guy.
I just had a client tell me they are perfectly fine with inaccurate results. Every query in the databases employs the nolock hint. Yes - every query.
When asking them if it was ok if they over/undercharged a client or if their financials were wrong - they said it's ok because somebody will probably just rerun them anyway.
Bernie Madov's still trading?
I'm a DBA.
I'm not paid to solve problems. I'm paid to prevent them.
March 17, 2014 at 6:45 am
I just love the way a couple of heavy IO operations turns my (5 month old) laptop into a paperweight. Busy shrinking one DB and zipping the backup of another and now opening Word takes over a minute, Outlook's been loading for 2 min and getting a new query window takes long enough that I can get coffee during the process. 🙁
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
March 17, 2014 at 7:55 am
GilaMonster (3/17/2014)
I just love the way a couple of heavy IO operations turns my (5 month old) laptop into a paperweight. Busy shrinking one DB and zipping the backup of another and now opening Word takes over a minute, Outlook's been loading for 2 min and getting a new query window takes long enough that I can get coffee during the process. 🙁
Hope you've been feeding the pigeons
---------------------------------------------------------
How best to post your question[/url]
How to post performance problems[/url]
Tally Table:What it is and how it replaces a loop[/url]
"stewsterl 80804 (10/16/2009)I guess when you stop and try to understand the solution provided you not only learn, but save yourself some headaches when you need to make any slight changes."
March 17, 2014 at 8:09 am
GilaMonster (3/17/2014)
I just love the way a couple of heavy IO operations turns my (5 month old) laptop into a paperweight. Busy shrinking one DB and zipping the backup of another and now opening Word takes over a minute, Outlook's been loading for 2 min and getting a new query window takes long enough that I can get coffee during the process. 🙁
Is that not an SSD you have in there? If it's spinning rust then yes, that sounds about right--you've probably got a disk queue length somewhere a long way north of where you'd like it. 🙂
March 17, 2014 at 8:11 am
paul.knibbs (3/17/2014)
GilaMonster (3/17/2014)
I just love the way a couple of heavy IO operations turns my (5 month old) laptop into a paperweight. Busy shrinking one DB and zipping the backup of another and now opening Word takes over a minute, Outlook's been loading for 2 min and getting a new query window takes long enough that I can get coffee during the process. 🙁Is that not an SSD you have in there?
Nope. If I want an SSD in my work notebook, I have to buy one myself. Disk utilisation at 100%, couple hundred hard page faults/sec and 85% memory in use.
Reminds me why I always go for multiple drives when building my home desktop. SQL hammering its databases doesn't kill the OS or break my games.
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
March 17, 2014 at 8:51 am
Had an interesting question from my kid last night. He is studying for a GIS test and was confused about the phases of database design
- conceptual
- logical
- physical
I found a few references (http://www2.amk.fi/digma.fi/www.amk.fi/opintojaksot/0303011/1146161367915/1146161680673/1146161874577/1146161968355.html), but couldn't give him good examples of how #1 and #2 differentiate. I've tended to blur them together in my past.
Any succinct explanations?
March 17, 2014 at 8:52 am
GilaMonster (3/17/2014)
paul.knibbs (3/17/2014)
GilaMonster (3/17/2014)
I just love the way a couple of heavy IO operations turns my (5 month old) laptop into a paperweight. Busy shrinking one DB and zipping the backup of another and now opening Word takes over a minute, Outlook's been loading for 2 min and getting a new query window takes long enough that I can get coffee during the process. 🙁Is that not an SSD you have in there?
Nope. If I want an SSD in my work notebook, I have to buy one myself. Disk utilisation at 100%, couple hundred hard page faults/sec and 85% memory in use.
Reminds me why I always go for multiple drives when building my home desktop. SQL hammering its databases doesn't kill the OS or break my games.
You must not be using NOLOCK.
It fixes all performance issues!
March 17, 2014 at 9:00 am
Steve Jones - SSC Editor (3/17/2014)
Had an interesting question from my kid last night. He is studying for a GIS test and was confused about the phases of database design- conceptual
- logical
- physical
I found a few references (http://www2.amk.fi/digma.fi/www.amk.fi/opintojaksot/0303011/1146161367915/1146161680673/1146161874577/1146161968355.html), but couldn't give him good examples of how #1 and #2 differentiate. I've tended to blur them together in my past.
Any succinct explanations?
Not a hard stretch to blur them.
Maybe going from the standpoint of getting an understanding of what data is related and the where the dependencies fall(conceptual), then you can map data to tables (logical).
Once you have it mapped and the tables designed - then start down the path of physical layout on disk.
Jason...AKA CirqueDeSQLeil
_______________________________________________
I have given a name to my pain...MCM SQL Server, MVP
SQL RNNR
Posting Performance Based Questions - Gail Shaw[/url]
Learn Extended Events
March 17, 2014 at 9:12 am
Steve Jones - SSC Editor (3/17/2014)
Had an interesting question from my kid last night. He is studying for a GIS test and was confused about the phases of database design- conceptual
- logical
- physical
I found a few references (http://www2.amk.fi/digma.fi/www.amk.fi/opintojaksot/0303011/1146161367915/1146161680673/1146161874577/1146161968355.html), but couldn't give him good examples of how #1 and #2 differentiate. I've tended to blur them together in my past.
Any succinct explanations?
Conceptual includes the tables and just the idea that they relate to one another.
It would also include fields / attributes.
Logical will include more detail - how the tables actually relate to each other (FK's). And may break some tables into more normalized structure to minimize redundancy.
Yes, they do tend to be hard to separate out. As I am in the conceptual phase, I find myself filling in more details about the logical layer.
So I go back and forth, and may even start the physical mapping before finishing conceptual and logical.
March 17, 2014 at 9:26 am
From a presentation on design I did recently:
Business Analysis/Conceptual design
Process of gathering requirements
Identify entities
Identify attributes
Identify business rules
Produces a conceptual model
Logical Design
Refining of the conceptual model
Define the full set of entities that define the system
Define the full set of attributes for each entity
Identify the candidate keys for each entity
Define the relationships between the entities and their cardinality
Identify the domain for each attribute
Normalise
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
March 17, 2014 at 10:37 am
Lots of repetition in the explanations here. Anyone have a good entity example that shows the difference? As I explain this, it sounds as though "more detail in the logical model" is what everyone thinks, but I'm not sure that's a good definition.
March 17, 2014 at 11:39 am
Steve Jones - SSC Editor (3/17/2014)
Lots of repetition in the explanations here. Anyone have a good entity example that shows the difference? As I explain this, it sounds as though "more detail in the logical model" is what everyone thinks, but I'm not sure that's a good definition.
See if this[/url] is clear enough.
There is overlap. Each adds to the picture, where physical gets into the specific platform.
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