📄 st_b5772.out
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ij> autocommit off;ij> create table foo (a int, b char(250), c char(250), d int);0 rows inserted/updated/deletedij> insert into foo values (1, '1', '1', 1);1 row inserted/updated/deletedij> insert into foo values (11, '11', '1', 1);1 row inserted/updated/deletedij> insert into foo values (12, '12', '1', 1);1 row inserted/updated/deletedij> insert into foo values (13, '13', '1', 1);1 row inserted/updated/deletedij> insert into foo values (14, '14', '1', 1);1 row inserted/updated/deletedij> insert into foo values (15, '15', '1', 1);1 row inserted/updated/deletedij> insert into foo values (16, '16', '1', 1);1 row inserted/updated/deletedij> insert into foo values (17, '17', '1', 1);1 row inserted/updated/deletedij> insert into foo values (18, '18', '1', 1);1 row inserted/updated/deletedij> insert into foo values (11, '111', '1', 1);1 row inserted/updated/deletedij> insert into foo values (12, '121', '1', 1);1 row inserted/updated/deletedij> insert into foo values (13, '131', '1', 1);1 row inserted/updated/deletedij> insert into foo values (14, '141', '1', 1);1 row inserted/updated/deletedij> insert into foo values (15, '151', '1', 1);1 row inserted/updated/deletedij> insert into foo values (16, '161', '1', 1);1 row inserted/updated/deletedij> insert into foo values (17, '171', '1', 1);1 row inserted/updated/deletedij> insert into foo values (18, '181', '1', 1);1 row inserted/updated/deletedij> insert into foo values (2, '2', '1', 1);1 row inserted/updated/deletedij> insert into foo values (3, '3', '1', 1);1 row inserted/updated/deletedij> insert into foo values (4, '4', '1', 1);1 row inserted/updated/deletedij> insert into foo values (5, '5', '1', 1);1 row inserted/updated/deletedij> insert into foo values (6, '6', '1', 1);1 row inserted/updated/deletedij> insert into foo values (7, '7', '1', 1);1 row inserted/updated/deletedij> insert into foo values (8, '8', '1', 1);1 row inserted/updated/deletedij> insert into foo values (9, '9', '1', 1);1 row inserted/updated/deletedij> create index foox on foo (b);0 rows inserted/updated/deletedij> -- normal max optimization, last row in index is not deleted.select max(b) from foo;1 --------------------------------------------------------------------------------------------------------------------------------9 &ij> -- new max optimization, last row in index is deleted but others on page aren't.delete from foo where a = 9;1 row inserted/updated/deletedij> select max(b) from foo;1 --------------------------------------------------------------------------------------------------------------------------------8 &ij> -- new max optimization, last row in index is deleted but others on page aren't.delete from foo where a = 8;1 row inserted/updated/deletedij> select max(b) from foo;1 --------------------------------------------------------------------------------------------------------------------------------7 &ij> -- new max optimization, last row in index is null, real max on last page.insert into foo values (9, null, '1', 1);1 row inserted/updated/deletedij> select max(b) from foo;1 --------------------------------------------------------------------------------------------------------------------------------7 &ij> -- new max optimization, last is null and deleted, real max on last page.delete from foo where a > 2;22 rows inserted/updated/deletedij> select max(b) from foo;1 --------------------------------------------------------------------------------------------------------------------------------2 &ij> -- max optimization does not work - fail over to scan, all rows on last page are-- deleted, except for non-deleted null row on last page. max row on 1st page.delete from foo where a > 1;1 row inserted/updated/deletedij> insert into foo values (9, null, '1', 1);1 row inserted/updated/deletedij> select max(b) from foo;1 --------------------------------------------------------------------------------------------------------------------------------1 &ij> -- max optimization does not work - fail over to scan, all rows on last page are-- deleted. non-deleted null row on last page. max row is on 1st page.delete from foo where a > 1;1 row inserted/updated/deletedij> select max(b) from foo;1 --------------------------------------------------------------------------------------------------------------------------------1 &ij> create table b5772 (a int, b int);0 rows inserted/updated/deletedij> create index b1 on b5772(b);0 rows inserted/updated/deletedij> -- 0 row caseselect max(b) from b5772;1 -----------NULL ij> select min(b) from b5772;1 -----------NULL ij> -- 1 row caseinsert into b5772 values (1, 1);1 row inserted/updated/deletedij> select max(b) from b5772;1 -----------1 ij> select min(b) from b5772;1 -----------1 ij> -- 1 null row casedrop table b5772;0 rows inserted/updated/deletedij> create table b5772 (a int, b int);0 rows inserted/updated/deletedij> create index b1 on b5772(b);0 rows inserted/updated/deletedij> insert into b5772 values (2, null);1 row inserted/updated/deletedij> select max(b) from b5772;1 -----------NULL ij> select min(b) from b5772;1 -----------NULL WARNING 01003: Null values were eliminated from the argument of a column function.ij> -- 1 row plus, one null row.insert into b5772 values (1, 1);1 row inserted/updated/deletedij> -- cleanupdrop table b5772;0 rows inserted/updated/deletedij> drop table foo;0 rows inserted/updated/deletedij> commit;ij> ⌨️ 快捷键说明
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