SID and PID

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SID and PID

m.rajesh.uk

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June 3, 2013 at 11:22 pm

#294134

Hi can any one explain what these SID and PID . what is the use of them..

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Gail Shaw SSC Guru Points: 1004504 More actions · Answer 1

In what context? As seen where?

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

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m.rajesh.uk Hall of Fame Points: 3653 More actions · Answer 2

m.rajesh.uk

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June 4, 2013 at 4:07 am

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Asked in the interview Gail.

Kingston Dhasian SSCoach Points: 19799 More actions · Answer 3

m.rajesh.uk (6/4/2013)
Hi can any one explain what these SID and PID . what is the use of them..

Are these column names from some system tables?

Kingston Dhasian

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hvermaak SSChasing Mays Points: 642 More actions · Answer 4

All I can think of is the process identifier used in task manager and the security identifiers as used in syslogins which uniquely identifies and entity.

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 5

m.rajesh.uk (6/4/2013)
Asked in the interview Gail.

Then not enough context to answer. I would have asked the interviewer to clarify his question. They're probably identifiers, but what they're identifying depends on what context is being asked.

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

m.rajesh.uk Hall of Fame Points: 3653 More actions · Answer 6

Thanks for every one for your valuable time in answering the issues i am getting.

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 7

btw, if I was asked the meaning of some obscure column in a system table in an interview, my answer would be 'if I need to know that, I'll look it up in Books Online, where all the system tables are well documented"

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

HowardW One Orange Chip Points: 29109 More actions · Answer 8

They're typically Oracle terms. SID would most closely relate to SPID in SQL Server and PID to the OS level process ID.

There's no direct correlation to SQL Server, as in Oracle, with default settings (dedicated server process), each user connection would have a OS-level process to itself, therefore you'd have one PID for each SID. In Shared mode, you'd have multiple SIDs to PIDs, but still likely to be more than one PID. Then, other functions of the Oracle Database are handled by other processes that communicate with each other, each of which have their own PIDs.

In SQL Server, there's only one OS-level process (sqlservr.exe), which handles all operations of the SQL Server engine.

Lynn Pettis SSC Guru Points: 442467 More actions · Answer 9

HowardW (6/4/2013)
They're typically Oracle terms. SID would most closely relate to SPID in SQL Server and PID to the OS level process ID.
There's no direct correlation to SQL Server, as in Oracle, with default settings (dedicated server process), each user connection would have a OS-level process to itself, therefore you'd have one PID for each SID. In Shared mode, you'd have multiple SIDs to PIDs, but still likely to be more than one PID. Then, other functions of the Oracle Database are handled by other processes that communicate with each other, each of which have their own PIDs.
In SQL Server, there's only one OS-level process (sqlservr.exe), which handles all operations of the SQL Server engine.

Actually, SID is the security id in SQL Server. PID is more likely synonymous with SPID in SQL Server.

From the definition of SID in sys.server_principals:

SID (Security-IDentifier) of the principal. If Windows principal, then it matches Windows SID.

HowardW One Orange Chip Points: 29109 More actions · Answer 10

Lynn Pettis (6/4/2013)
Actually, SID is the security id in SQL Server. PID is more likely synonymous with SPID in SQL Server.
From the definition of SID in sys.server_principals:
SID (Security-IDentifier) of the principal. If Windows principal, then it matches Windows SID.

Sure, SID is an acronym used in SQL Server, but the two together in an interview are likely to be referring to Oracle (although I can only guess).

In Oracle terms, the SID is roughly equivalent to SPID, as it's the internal identifier for a session, whereas PID is the actual OS level process ID from Linux/Windows.

Lynn Pettis SSC Guru Points: 442467 More actions · Answer 11

I wouldn't assume Oracle unless I actually saw something that looked Oracle, like CREATE OR REPLACE. This was posted on a SQL Server forum with not (or actually any) real details. At this point I would think SQL Server still.