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- 4D Language Reference
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- Cache Management
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Managing priorities in database cache
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ADJUST BLOBS CACHE PRIORITY
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ADJUST INDEX CACHE PRIORITY
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ADJUST TABLE CACHE PRIORITY
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Cache info
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FLUSH CACHE
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Get adjusted blobs cache priority
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Get adjusted index cache priority
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Get adjusted table cache priority
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Get cache size
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GET MEMORY STATISTICS
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SET BLOBS CACHE PRIORITY
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SET CACHE SIZE
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SET INDEX CACHE PRIORITY
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SET TABLE CACHE PRIORITY
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ADJUST BLOBS CACHE PRIORITY
| ADJUST BLOBS CACHE PRIORITY ( aTable ; priority ) | ||||||||
| Parameter | Type | Description | ||||||
| aTable | Table |
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Table whose "blobs" data priority value has to be adjusted | |||||
| priority | Longint |
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Cache priority value for BLOBs in the table | |||||
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 |
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)
Product: 4D
Theme: Cache Management
Number:
1431
Created: 4D v16 R2
4D Language Reference ( 4D v20 R7)
