Viewing 15 posts - 28,576 through 28,590 (of 49,552 total)
Nadrek (1/7/2011)
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
January 7, 2011 at 2:33 pm
tfifield (1/7/2011)
Are they a double linked list? I see from the diagrams that they link forward. Do they link backwards also?
Yes. If it's not in the diagram, it's...
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
January 7, 2011 at 2:32 pm
Kevin Wood-419472 (1/7/2011)
Great article series. I'm trying to determine what is meant by "left-based subset".
A subset of the index key, reading from the left.
eg an index on (Col1, Col2,...
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
January 7, 2011 at 2:29 pm
TalkToLee (1/7/2011)
vs.
level #3 of this index...
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
January 7, 2011 at 2:29 pm
p.s. There are several very good index rebuild scripts already written and available for use. Don't reinvent the wheel.
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
January 7, 2011 at 9:18 am
In general, in most cases, worry about the leaf level and no other. The higher levels of the index are generally not large enough for fragmentation to matter, and they're...
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
January 7, 2011 at 9:16 am
It's not a seek because there's no predicate. A seek occurs when there's some defined value to search for. It's a backward scan that aborts after 1 page because it...
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
January 7, 2011 at 5:39 am
What is the data type of the column?
What query are you running?
Please remember we can't see what you're doing. The more info you give, the more likely it is...
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
January 7, 2011 at 5:37 am
What's the error?
What's the data type of the column?
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
January 7, 2011 at 5:11 am
Ok, so that statement needs to be amended to 'In normal cases ...' I wasn't thinking about TOP when I wrote that. Do note though, max on a column that's...
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
January 7, 2011 at 4:52 am
It depends. Among other things it depends on what data is going to be missing.
Thinking back to the bank there were some tables that we could do without during business...
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
January 7, 2011 at 4:00 am
It depends. Not enough information to answer that question
What are the queries that you're creating the index for? What's the table structure?
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
January 7, 2011 at 3:55 am
You don't attach a backup file. You restore a backup file.
RESTORE DATABASE <dbName> FROM DISK = <Backup file name>
Exactly what are you trying to do? (step by step or...
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
January 7, 2011 at 3:55 am
Try them out with statistics IO on and compare the logical reads with the number of pages in the table.
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
January 7, 2011 at 3:52 am
It would throw an error.
Error 666, Severity 16
The maximum system-generated unique value for a duplicate group was exceeded for index with partition ID <Partition ID>. Dropping and re-creating the...
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
January 7, 2011 at 2:36 am
Viewing 15 posts - 28,576 through 28,590 (of 49,552 total)