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Topic: How SQL the server works with a disk?

Good afternoon;
There was a question: what portions of data SQL exchanges with a disk.
In subconsciousness the digit 64 but when tried to find its substantiation could not sits:
- At Microsoft found such articles:
https://docs.microsoft.com/ru-ru/sql/re … ture-guide
https://docs.microsoft.com/ru-ru/sql/re … ding-pages
https://docs.microsoft.com/ru-ru/sql/re … ting-pages
From which explicitly does not follow, what even read operations are fulfilled by units on 64 - is told only that operation dataful happens at level of pages - i.e. 8. Also there is an advancing reading which can read to 512 for time, but a minimum probably 8, instead of 64, at least at reading of indexes.
Operation possibly happens to a broad gull in smaller portions - on one record.
Share, if know, clever articles from MS where more accurately describe a physical disk swapping, and whether it is possible to influence any adjustments the size of portions of a disk swapping?
p.s. The question arose on 2012 versions, but I think with 2000-2005 a little that changed in this part.
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That does not become, all to the best.

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Re: How SQL the server works with a disk?

Denis;
Reads extents 8 on 8 = 64. But more often takes at once and adjacent

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Re: How SQL the server works with a disk?

Reads differently. Can look in sys.dm_os_virtual_file_stats.

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Re: How SQL the server works with a disk?

Denis;
Read
https://www.codeproject.com/Articles/63 … es-a-query

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Re: How SQL the server works with a disk?

Denis;
More 64 do not spring, the maximum cluster size NTFS.

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Re: How SQL the server works with a disk?

Vladislav Kolosov;
And here clusters NTFS???
One extent is not one page and not one cluster.
Denis;
Digit "64" sat down since SQL 2000 when really there was an exchange with disk the given units 8  8 (page) and a broad gull 2  2.
By default it, of course, and now can be so - but this parameter for a long time already changed.

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Re: How SQL the server works with a disk?

wrote:

One extent is not one page and not one cluster.

Decade apparently?

wrote:

By default it, of course, and now can be so - but this parameter for a long time already changed.

Where? It is possible to make less 64?

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Re: How SQL the server works with a disk?

It is possible to be guided on number of logical reads in respect of request.
One logical read = 8.
Truth the data can be both  and .

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Re: How SQL the server works with a disk?

Denis;
https://blog.purestorage.com/what-is-sq … lock-size/

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Re: How SQL the server works with a disk?

TaPaK wrote:

it is passed...
Decade apparently?
it is passed...
Where? It is possible to make less 64?

And what for it generally to do, if not a secret? To reduce, in sense, volume of one extent? When all aspire to read units more and to shift them .

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Re: How SQL the server works with a disk?

Goats wrote:

It is possible to be guided on number of logical reads in respect of request.
One logical read = 8.
Truth the data can be both  and .

, you will not check, but logical read it just from a cache

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Re: How SQL the server works with a disk?

a_shats wrote:

it is passed...
And what for it generally to do, if not a secret? To reduce, in sense, volume of one extent? When all aspire to read units more and to shift them .

The size of an extent can be changed?

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Re: How SQL the server works with a disk?

TaPaK wrote:

the size of an extent can be changed?

Well if only to enumerate for decades.
And so by determination it is beaten:  = 8 pages

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Re: How SQL the server works with a disk?

o-o wrote:

it is passed...
Well if only to enumerate for decades.
And so by determination it is beaten:  = 8 pages

Well

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Re: How SQL the server works with a disk?

o-o wrote:

it is passed...
Well if only to enumerate for decades.
And so by determination it is beaten:  = 8 pages

At recalculation for decades there is no the unambiguous method truly to count.

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Re: How SQL the server works with a disk?

Denis;
What for to you? All the same cannot change it;
Is better would tell, what task solve

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Re: How SQL the server works with a disk?

The critic;
Yes probably on interview did not know how to get off.