GETCHUNKSIZE Function

When creating the table, you can specify the chunking factor, which can be a multiple of Oracle blocks. This corresponds to the chunk size used by the LOB data layer when accessing or modifying the LOB value. Part of the chunk is used to store system-related information, and the rest stores the LOB value.

This function returns the amount of space used in the LOB chunk to store the LOB value.

Syntax

DBMS_LOB.GETCHUNKSIZE (
   lob_loc IN BLOB) 
  RETURN INTEGER; 

DBMS_LOB.GETCHUNKSIZE (
   lob_loc IN CLOB CHARACTER SET ANY_CS) 
  RETURN INTEGER; 

Pragmas

pragma restrict_references(GETCHUNKSIZE, WNDS, RNDS, WNPS, RNPS); 

Parameters

Table 22-27 GETCHUNKSIZE Function Parameters

Parameter	Description
lob_loc	LOB locator.

Returns

The value returned for BLOBs is in terms of bytes. The value returned for CLOBs is in terms of characters.

Usage Notes

Performance is improved if you enter read/write requests using a multiple of this chunk size. For writes, there is an added benefit, because LOB chunks are versioned, and if all writes are done on a chunk basis, then no extra or excess versioning is done or duplicated. You could batch up the WRITE until you have enough for a chunk, instead of issuing several WRITE calls for the same chunk.