ADJUST BLOBS CACHE PRIORITY

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4D v20.6


ADJUST BLOBS CACHE PRIORITY ( aTable ; priority )

Parameter	Type	Description
aTable	Table	Table whose "blobs" data priority value has to be adjusted
priority	Longint	Cache priority value for BLOBs in the table

Expert mode

This command is reserved for specific needs. It must be used with care since it can affect database performance.

The ADJUST BLOBS CACHE PRIORITY command modifies the priority of the "blobs" data related to aTable in cache for the current process. A call to this command replaces any priority previously adjusted through the same command in the same process. This command adjusts the priority for a temporary need, for example during a query or an import.

Note: This command only works in local mode (4D Server and 4D); it cannot be used in 4D remote mode.

"Blobs" data field types include BLOB, text, picture, and object. This command handles priority for such data when they are stored in the data file only. Priority for fields of scalar type (such as date, number, or string types) is adjusted by the ADJUST TABLE CACHE PRIORITY command.

Pass one of the following constants from the "Cache Management" theme in the priority parameter:

Constant	Comment
Cache priority low
Cache priority very low
Cache priority normal	Sets the cache priority to its default value
Cache priority high
Cache priority very high

Example

You want to temporarily change the cache priority for the [Docs] table text fields stored in the data file when executing a sequential search:

 ADJUST BLOBS CACHE PRIORITY([Docs];Cache priority very high)

 QUERY([Docs];[Docs]Author#"A@") // sequential search on a non indexed field

  //... run several other queries or sorts on the same table

  // when finished, set back to normal cache priority

 ADJUST BLOBS CACHE PRIORITY([Docs];Cache priority normal)