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James Bailey
James Bailey
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The (NOLOCK) optimizer hint is well known by most SQL developers for setting the isolation level so that tables with rows or escalated page locks can be read. I've always known about the bad and ugly; dirty reads, errors, dup rows that can occur. My specific question is why is it so overused in every organization I tend to consult with? I've seen it used for every select statement on every table in the last 3 clients I've been at. These are OLTP systems. Not and not replicated data that is read only. What are the possible reasons for this? Is the memory/hardware insufficient to get transactions processed? Is data consistency less important than it used to be? What is the general consensus and best practice on using NOLOCK?

The (NOLOCK) optimizer hint is well known by most SQL developers for setting the isolation level so that tables with rows or escalated page locks can be read. I've always known about the bad and ugly; dirty reads, errors, dup rows that can occur. My specific question is why is it so overused in every organization I tend to consult with? I've seen it used for every select statement on every table in the last 3 clients I've been at. These are OLTP systems. Not replicated data that is read only. What are the possible reasons for this? Is the memory/hardware insufficient to get transactions processed? Is data consistency less important than it used to be? What is the general consensus and best practice on using NOLOCK?

The (NOLOCK) optimizer hint is well known by most SQL developers for setting the isolation level so that tables with rows or escalated page locks can be read. I've always known about the bad and ugly; dirty reads, errors, dup rows that can occur. My specific question is why is it so overused in every organization I tend to consult with? I've seen it used for every select statement on every table in the last 3 clients I've been at. These are OLTP systems and not replicated data that is read only. What are the possible reasons for this? Is the memory/hardware insufficient to get transactions processed? Is data consistency less important than it used to be? What is the general consensus and best practice on using NOLOCK?

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James Bailey
James Bailey
  • 193
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  • 7

The (NOLOCK) optimizer hint is well known by most SQL developers for setting the isolation level so that tables with rows or escalated page locks can be read. I've always known about the bad and ugly; dirty reads, errors, dup rows that can occur. My specific question is why is it so overused in every organization I tend to consult with? I've seen it used for every select statement on every tablestable in the last 3 clients I've been at. These are OLTP systems. Not replicated data that is read only. What are the possible reasons for this? Is the memory/hardware insufficient to get transactions processed? Is data consistency less important than it used to be? What is the general consensus and best practice on using NOLOCK?

The (NOLOCK) optimizer hint is well known by most SQL developers for setting the isolation level so that tables with rows or escalated page locks can be read. I've always known about the bad and ugly; dirty reads, errors, dup rows that can occur. My specific question is why is it so overused in every organization I tend to consult with? I've seen it used for every select statement on every tables in the last 3 clients I've been at. What are the possible reasons for this? Is the memory/hardware insufficient to get transactions processed? Is data consistency less important than it used to be? What is the general consensus and best practice on using NOLOCK?

The (NOLOCK) optimizer hint is well known by most SQL developers for setting the isolation level so that tables with rows or escalated page locks can be read. I've always known about the bad and ugly; dirty reads, errors, dup rows that can occur. My specific question is why is it so overused in every organization I tend to consult with? I've seen it used for every select statement on every table in the last 3 clients I've been at. These are OLTP systems. Not replicated data that is read only. What are the possible reasons for this? Is the memory/hardware insufficient to get transactions processed? Is data consistency less important than it used to be? What is the general consensus and best practice on using NOLOCK?

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James Bailey
James Bailey
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Use of NOLOCK on Microsoft SQL Server

The (NOLOCK) optimizer hint is well known by most SQL developers for setting the isolation level so that tables with rows or escalated page locks can be read. I've always known about the bad and ugly; dirty reads, errors, dup rows that can occur. My specific question is why is it so overused in every organization I tend to consult with? I've seen it used for every select statement on every tables in the last 3 clients I've been at. What are the possible reasons for this? Is the memory/hardware insufficient to get transactions processed? Is data consistency less important than it used to be? What is the general consensus and best practice on using NOLOCK?