The same basic execution logic is used to handle all four of the basic SQL query types:
DELETE. For example, when doing an
UPDATE, the identified rows to update are found in a familiar way and then fed to an
EXPLAIN ANALYZE UPDATE customers SET state=state WHERE customerid=1; QUERY PLAN ---------- Update (cost=0.00..0.28 rows=1 width=274) (actual time=63.289..63.289 rows=0 loops=1) -> Index Scan using customers_pkey on customers (cost=0.00..0.28 rows=1 width=274) (actual time=0.054..0.063 rows=1 loop s=1) Index Cond: (customerid = 1) Total runtime: 63.415 ms
DELETE can execute efficiently by keeping track of the tuple ID uniquely identifying each of the rows ...