I have several questions:
1) If Oracle manages both High-water Mark and Low High-water Mark in ASSM tablespace then do we have to think about that when thinking about performance? I mean, does Oracle manages deleted blocks itself and does not scan those blocks during table full scan, or do we still have to shrink those tables (alter table mytable shrink space;) in order to clean those deleted blocks and increase performance?
2) If ASSM gives automatisation for this and other related stuff then no doubtfully there's a performance trade-offs when choosing ASSM instead of MSSM. What should be major criteria on choosing ASSM or MSSM?
UPDATE. I did a test on my laptop with mytable (ASSM). First, inserted 1.000.000 records. Query "select count(*) from mytable" was executing at average 0.05 s. Then did full DELETE. The same query was executing at average 0.03 s, so maybe Oracle was still reading deleted blocks. Only after TRUNCATE the query executed at average 0.001 s. Maybe ASSM takes time to shrink table space, or still I have manually to shrink it?