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Informational Parameters

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Applies to: Windows | Windows Server

Informational Parameters

This topic contains parameters that are used to expose information about the database engine.

JET_paramKeyMost
134

This read-only parameter indicates the maximum allowable index key length that can be selected for the current database page size (as configured by JET_paramDatabasePageSize).

Label Value

Default Value:

JET_cbKeyMost4KBytePage

Type:

Integer

Valid Range:

255 – 65535

Scope:

Global

Set After JetCreateInstance:

N/A

Set after JetInit:

N/A

Affects Physical Layout:

No

Affects Reliability:

No

Affects Performance:

No

Affects Resources:

No

Availability:

Starting with Windows Server 2008 and Windows Vista

JET_paramMaxColtyp
131

This read only parameter returns the maximum JET_COLTYP (JET_coltypMax) for that version of the database engine. This value can be used to test for support of a specific JET_COLTYP. If a given JET_COLTYP is less than the value of this parameter then it is supported by the database engine.

Label Value

Default Value:

JET_coltypUnsignedShort + 1

Type:

Integer

Valid Range:

0 – 255

Scope:

Global

Set After JetCreateInstance:

N/A

Set after JetInit:

N/A

Affects Physical Layout:

No

Affects Reliability:

No

Affects Performance:

No

Affects Resources:

No

Availability:

Starting with Windows Server 2008 and Windows Vista

JET_paramLVChunkSizeMost
163

Read only parameter that returns the long-value chunk size based on configured page size. If a long-value is to be read or written with multiple Jet{Set,Retrieve}Column calls then using a buffer whose size is a multiple of the chunk size is more efficient.

Label Value

Default Value:

2kb page = 1966 bytes
4kb page = 4014 bytes
8kb page = 8110 bytes
16kb page = 4050 bytes
32kb page = 8150 bytes

Type:

Integer

Valid Range:

0-10000

Scope:

Set After JetCreateInstance:

Set after JetInit:

Affects Physical Layout:

Affects Reliability:

Affects Performance:

Affects Resources:

Availability:

Requirements

Requirement Value

Client

Requires Windows Vista.

Server

Requires Windows Server 2008.

Header

Declared in Esent.h.

See Also

JetCreateInstance
JetInit
JET_COLTYP