This is a feature that aligns the starting address of Extents to a specified size unit (Alignment) when allocating space (Extent) in Bitmap-type Tablespaces.

The alignment unit (_TX_TS_ALIGNED_ALLOC_SIZE) is in bytes.

To prevent fragmentation, alignment is applied only to space requests larger than the configured parameter value.

Example: When set to 4MB, alignment is applied only to Extent allocation requests of 4MB or larger.

If the feature is disabled, the allocation proceeds as before by searching for contiguous free units from the front.

<Caution>
This patch cannot apply alignment to existing files created before the parameter was set; alignment can only be applied to new files created after the parameter is set. (Files created after setting USE_ALIGNED_ALLOCATE = Y)

Whether a file supports alignment can be confirmed in the ALIGNED column of V$DATAFILE_BM (VT_DATAFILE_BM).

TXTS_ALIGNED_ALLOC_SIZE can only be set as a multiple of (16 × DB_BLOCK_SIZE).

FS02PS_700438a

No incompatible items

• TAC Rolling Patch: Supported

• TSC Rolling Patch: Supported

• Backup Data Compatibility: Supported

• Protocol Compatibility: Supported

• Data Format Compatibility: Supported

• Plan change: No

• Result value change: No

• SQL syntax change: No

• System object change: No

• Existing feature change: No

Parameter Name: _TX_TS_ALIGNED_ALLOC_SIZE
• Type: CREATE
• Tip Type: DB
• Description: Sets the alignment unit in bytes to align the starting address of Extents when allocating space in Tablespace Bitmap.

If the requested space is smaller than the parameter value, allocation proceeds as before from the front free units.

<Cautions>

1. Alignment can only be applied to data files created after setting _TX_USE_ALIGNED_ALLOCATE to Y. Such data files do not use the first 16 blocks and can be confirmed via the ALIGNED column in the _vt_datafile_bm view.
2. Setting the parameter to 0 disables alignment.
3. Alignment is applied only when the requested space is equal to or larger than the parameter value to prevent fragmentation.

For example, if the parameter is set to 4MB, alignment applies only to space requests of 4MB or more.

• Disable Value: 0
• Parameter Type: Integer
• Default Value: 0
• Class: Optional, Adjustable, Dynamic, SYSTEM
• Range: 0 ~ UINT32MAX

Parameter Name: _TX_USE_ALIGNED_ALLOCATE

• Type: CREATE

• Tip Type: DB

• Description: Sets whether to align the Extent address according to the ALIGNED_ALLOC_SIZE setting when allocating space in Tablespace Bitmap.

Data files created after enabling this parameter are generated with alignment capability.

Data files created after disabling this parameter cannot apply alignment.

• Parameter Type: Boolean
• Default Value: N
• Class: Optional, Adjustable, Static, SYSTEM
• Range: -