3 ms·
Pretty well all modern commercial DBs do use summary (or sampled?) statistics of the cardinalities. The alternative is rule-based rewriters which were heuristic
by zasdffaa 4y ago
Pretty well all modern commercial DBs do use summary (or sampled?) statistics of the cardinalities. The alternative is rule-based rewriters which were heuristically-driven only, and AFAIK they justifiably went out of use decades ago.