Comments for SQL Fascination

Comment on Rolling a Partition Forward – Part 2 by andrewhogg

andrewhogg — Wed, 25 Aug 2010 07:16:38 +0000

Users and partitions have nothing in common, unless you are planning to use partitioning for multi-tenancy, which I do not believe is a good use of partitioning. More details here : http://sqlfascination.com/2010/01/05/

Comment on Guidance on How to Layout a Partitioned Table across Filegroups by andrewhogg

andrewhogg — Wed, 25 Aug 2010 07:12:03 +0000

It will depend on the variance and size of the data rows, depending on that variance I would take the disk space penalty, or opt for all partitions into a single filegroup and spread the filegroup’s files across all the disks. That technique has disavantages when it comes to the backup strategy, and will not perform as well since the filegroup will fragment over time.

Comment on Rolling a Partition Forward – Part 2 by developer

developer — Wed, 25 Aug 2010 05:18:21 +0000

Hi,
Can you please suggest what partitioning strategy is to be used for managing a large no:of user accounts?

Comment on Guidance on How to Layout a Partitioned Table across Filegroups by aparna

aparna — Wed, 25 Aug 2010 05:11:38 +0000

Hi,
What is the best strategy of partitioning if the quantity of data in each partition might vary considerably?

Comment on Finding Next Identity Value, and a Wild Goose Chase. by Matthijs

Matthijs — Tue, 27 Jul 2010 21:58:34 +0000

I just saw your post on stack overflow, and it was good. Found this blog in the same google. Also good is that you worked on answering the question, instead of questioning why the question was asked – if you catch my drift.

In my own case I was checking up reports from a user on missing records. I could see in the table no gaps in the ID order, so that told me the records had probably not been added and then physically deleted (there’s no ID re-set in this system). But how would I know if the missing records had been added at the “end” of the table or not? I needed to know the next ID, without actually making a record, to know if there was a “gap” at the “end” of the table.

Comment on Immutable Primary Key vs Immutable Clustered Key by andrewhogg

andrewhogg — Tue, 20 Jul 2010 19:33:50 +0000

You are right in that as a generic concept and the relevance of application to other databases / logical design it would provide more hits on a search engine for good reason – I am more interested in the physical implementation of a table design and impact on the database performance specifically from the SQL Server perspective – the choice of the clustering key is a key decision when implementing the logical design / data model.

The concept of a clustered table is not unique to SQL Server, Oracle’s Index Organised Tables would be akin and the same concepts could be explored there, but I’ve not tried to reverse a redo log as yet.

Comment on Immutable Primary Key vs Immutable Clustered Key by Kamal

Kamal — Tue, 20 Jul 2010 19:16:28 +0000

Hi Andrew,
thanks for this post!
I think the immutability of the Primary Key gets more attention because the reason behind it is logical (and not DBMS specific), whereas for the Clustering Key there is a physical reason (SQL Server specific).
I wouldn’t compare / relate the two reasons. When you model your data you might desire an immutable PK even before knowing what DBMS you’re going to use…

Cheers

–
Kamal

Comment on Guidance on How to Layout a Partitioned Table across Filegroups by andrewhogg

andrewhogg — Thu, 24 Jun 2010 12:29:16 +0000

Creating the initial partition script is not a problem, what you are probably having trouble with the the rolling of the partition window as a new month appears and an old month is to go. I have written a guide covering the harder parts of that process in two parts (part 1, part 2 )

Comment on Guidance on How to Layout a Partitioned Table across Filegroups by Marcelo

Marcelo — Wed, 23 Jun 2010 21:16:05 +0000

Hi
do you have the sample script to do this partition in months?

Comment on Query Parameterization and Wildcard Searches by Mark Pilkington

Mark Pilkington — Wed, 09 Jun 2010 09:34:43 +0000

Excellent…

will have to give this a try and see the results. We seem to have had an increase in ‘%?%’ like queries just lately!

thanks andrew

Comment on Locating Table Scans Within the Query Cache by pinaldave

pinaldave — Thu, 11 Mar 2010 00:23:39 +0000

Thanks,

This is for sure enhancement to original script.

Kind Regards,
Pinal

Comment on Dynamic Partitioning : What objects are using a Partition Schema? (SQL Tuesday #002) by Adam Machanic : T-SQL Tuesday #002: The Roundup

Adam Machanic : T-SQL Tuesday #002: The Roundup — Mon, 08 Feb 2010 19:16:12 +0000

[...] Hogg contributed a post in which he describes the trickery required to query the various DMVs in order to properly do dynamic partitioning. In the end, five views are needed to satisfy what at [...]

Comment on Finding Next Identity Value, and a Wild Goose Chase. by faheem

faheem — Wed, 20 Jan 2010 13:13:41 +0000

very nice

Comment on What is the SQL Server 2008 DateTime2 Internal Structure? by andrewhogg

andrewhogg — Tue, 13 Oct 2009 09:30:32 +0000

Your absolutely right, I’ve ended up copying the wrong thing out of the Query window and duplicated a result that should be different. I’ve updated the post with the correction.

Comment on What is the SQL Server 2008 DateTime2 Internal Structure? by BEL8490

BEL8490 — Tue, 13 Oct 2009 09:14:46 +0000

Thanks for this clarifying insight.

I would suggest two minor editing corrections:

1. The code at the beginning of the article does not have a declaration for the variable @bin1 and should be corrected as follows:
set @bin = CONVERT(varbinary(max), @dt)

2. At about halfway down the following example

’0180/06/06 00:00:00′ => 0x070000000000FFFF00
’0180/06/07 00:00:00′ => 0x070000000000FFFF00

should be corrected as:

’0180/06/06 00:00:00′ => 0x070000000000FFFF00
’0180/06/07 00:00:00′ => 0×070000000000000001

as clearly two different dates can not have the same internal presentation.