sql server 2005 - newid() vs newsequentialid() What are the differences/pros and cons? -

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In a database where all your primary keys are GUIDs, the difference / implication and / () versus the newly added () "default value or Binding "as

I know that the only difference is that the new () creates a new random GUID, because the new GUID builds against the new sequential () in the last one, which is in enlarged fashion in the table .

As I think, when you insert one in a row, Will be inserted in relative order. With a general guide, it can be anywhere in the table. A new sequential () will always be added at the end of the table.

Therefore the performance of the merge is improved.

Indicates the difference between the two different methods and the benchmark.

Update - The referenced blog post has been transferred. The link now refers to a web.archive.org link. Here's the main bad thing:

The most striking is the number of writing required by the newiid system function. This, along with the average page density of 69%, is the evidence of page division due to the random distribution of inserts at the leaf level. As soon as a page fills, 50% of each of them needs to be divided into 2 pages to complete it. Page is not only badting due to the density of the page, it has broken the data pages very badly (99% are likely to not have the next data page ahead of the current one). The most likely place for any free page needed for page breakdown in our tests is at the end of the table, even if the row is being inserted. Therefore, to read the rows, the scan needs to jump forward and back between the widely divided split pages, so frightening fragmentation.

- Stephen Delmarco


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