Archive for the ‘Articles’ Category

Procedure Cache – Memory Pressure

December 13, 2012 3 comments

_MG_2719Hi everyone,

Recently I was dealing with unusual behavior of Procedure Cache caused pseudo-random execution plans to be removed from memory (SQL Server 2005, 2008, 2008R2). As a result, under a large workload there was observed locks contention related to schema locks required in order to compile and insert a procedure into Procedure Cache. This is a predictable behavior of heavy loaded systems. But, the main question here is – how can we identify this type of issues related to so called Memory Pressure in Procedure Cache? Read more…

Categories: Memory, Uncategorized

Using fn_dblog

I like the fn_dblog function even if it is undocumented. It enables you to read from you transaction log which contains very valuable information about stuff that is happening in your database. It is for example the only way I now at this time to determin which object experienced a page split if you search for the LOP_DELETE_SPLIT operation.

FROM ::fn_dblog(NULL, NULL)

Read more…

Categories: News, SQL Server 2005 Tags: , ,

Do I have to assign the Lock Pages in Memory privilege for Local System?

This article has been written in the beginning of 2007 but, anyway, I face quite often with memory related issues dealing with costumers who are using Standard Edition of SQL Server. From my point of view it is worth to read this article through and systematize your knowledge about Locked Pages in SQL Server Standard Edition. Read more…

NEWSEQUENTIALID() – is it a panacea or not?

GUIDs and Clustered Indexes

Uniqueness is a key factor when synchronizing data within distributed environment, SQL Server/Azure and multiple endpoints like Slates and Smartphones, etc.  With data simultaneously created and updated on servers and clients, ensuring rows are unique to avoid key collisions is critical.  As you know, each row is uniquely identified by its Primary Key. Read more…

Categories: I/O, News Tags: , , ,

Mirroring in SQL Server 2008 Standard and Enterprise Editions

Both Standard and Enterprise versions of SQL Server have different lists of features which relate to DB mirroring. In order to be more familiar with such differences just go through this article. It could be very important if you a trying to implement some stuff on SQL Server Standard Edition and you just cannot because this version has several important restrictions. Read more…

Database Splitting into different File-Groups

During the process of database optimization database administrators quite often face with optimization of low-level I/O system. As a result, they try to split a database between different Disks, RAID-s, LUN-s, etc., in order to scale I/O workload out. This process is known also as “Database Splitting” between several logical I/O units. Read more…

FIBRE CHANNEL vs. iSCSI for SQL databases

April 10, 2011 1 comment

During last several years we saw a lot of battles around Storage Area Network technologies. The largest question there was which technology is better. If you know the answer, send me an email right now because I think it is impossible to have only one right answer thus different business requirements demand different characteristics from SAN. Read more…

Categories: Articles, I/O, News Tags: , ,