Which two statements are true regarding Oracle database space management within blocks managed by Automatic Segment Space Management (ASSM)?

Automatic Segment Space Management (ASSM) uses bitmaps to track the free space within each data block. It categorizes blocks based on their fullness to efficiently manage space for DML operations. This categorization allows Oracle to quickly find a suitable block for an insert. A fundamental task of ASSM during an insert is to locate a block with sufficient free space to accommodate the new row, which is a primary reason for its efficiency and for reducing block contention.

B: Row migration (relocating a row due to an update) only occurs if the updated row no longer fits in its original block; it is not an "always" operation. D: ASSM intentionally distributes inserts across multiple free blocks to avoid "hot block" contention, rather than always using the first available block. E: PCTFREE defaults to 10, but this can be overridden. Furthermore, its behavior is altered or ignored by features like Advanced Row Compression, so it does not apply universally.

1. Oracle Database Concepts, 23ai, "Automatic Segment Space Management". The documentation explains, "The database uses bitmaps to manage segment space in ASSM. The bitmaps... Track the status of each data block within a segment with respect to the amount of space available in the block."

2. Oracle Database Concepts, 23ai, "Space Management in Tablespaces". It describes how ASSM improves concurrency by "spreading out inserts among many blocks." This contradicts the idea of always using the first available block.

3. Oracle Database Administrator's Guide, 23ai, "Managing Space for Schema Objects". This guide details how ASSM automates the management of free space, which includes finding appropriate blocks for inserts.