1. When the `_TX_TS_ALIGNED_ALLOC_SIZE` parameter is set, the first Data Block Area (DBA) of a Tablespace Bitmap Unit allocated is aligned to a multiple of the configured value.

For example, if `_TX_TS_ALIGNED_ALLOC_SIZE` is set to `4M`, the starting address of the first block of every Extent that is 4MB or larger will be a multiple of 4MB.

2. The `_vt_datafile_bm` view allows querying the `LAST_DATA_BLKNO`, which is the last data block number available in the data file. If `(LAST_DATA_BLKNO + 1)` is a multiple of 16, the data file is aligned.

This patch supports rolling patching. Alignment is not applied to existing data files. Alignment is only applied to new data files created after the parameter is set.

1. Modify allocation of Tablespace Bitmap Units to apply alignment according to the `_TX_TS_ALIGNED_ALLOC_SIZE` parameter setting.

2. Modify the `_vt_datafile_bm` view to allow querying `LAST_DATA_BLKNO`. If `(LAST_DATA_BLKNO + 1)` is a multiple of 16, the data file supports alignment.

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 for the starting address of Extents when allocating Tablespace Bitmap space.

If a space smaller than the parameter value is requested, allocation proceeds as before from the front Free Unit.

<Precautions>

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 identified in the ALIGNED column of the _vt_datafile_bm view.
2. Setting the parameter to 0 disables alignment.
3. To prevent fragmentation, alignment is applied only when requesting space equal to or larger than the parameter value.

For example, if the parameter is set to 4MB, alignment applies only to 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: Determines whether to align Extent addresses according to the ALIGNED_ALLOC_SIZE setting when allocating Tablespace Bitmap space.

Data files created after enabling this parameter are created in a state that supports alignment.

Data files created after disabling this parameter do not support alignment.

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