.0.018 rows=0 loops=1) -> Filter: (t2.id > 1) (cost=0.35 rows=1) (actual time=0.016..0.016 rows=0 loops=1) -> Index scan on t2 using a2_uidx (cost=0.35 rows=1) (actual time=0.015..0.015 rows=0 loops=1) -> Single-row index lookup on t1 using PRIMARY (id=t2.id) (...
join数据,将两个结果集进行拼接 merges two record sets by looping through every record in the first set and trying to find a match in the second set. All matching records are returned. 遍历模式 索引模式 5、聚合 - Aggregate group by 操作 groups records together based on a GROUP BY or aggreg...
loops=2) 这里有几个新的度量: 获取第一行的实际时间以毫秒为单位) 获取所有行实际时间(以毫秒为单位 实际读取的行数 实际循环数 让看一个具体的示例,使用过滤条件的迭代成本估算和实际,该迭代过滤 2005 年 8 月的数据(上面 EXPLAIN ANALYZE 输出中的第 13 行)。 代码语言:javascript 代码运行次数...
Using Loops in Programming In most of the programming languages, three looping structures 'for', 'while', and 'do-while' are used to perform the statements that need to be executed repetitively until a given condition is satisfied. For example, the 'for' loop can be implemented (in C) as...
NESTED LOOPS TABLE ACCESS FULL Object owner=APPS Object name=HEK_TEST_INDETAIL TABLE ACCESS BY INDEX ROWID Object owner=APPS Object name=HEK_TEST_IN INDEX UNIQUE SCAN Object owner=APPS Object name=SYS_C00211467 分析得出:hek_test_in查询时使用索引扫描,而HEK_TEST_INDETAIL使用全表扫描。
Consider it like two embedded FOR loops. In Oracle Database 11g the internal implementation for nested loop joins changed to reduce overall latency for physical I/O so it is possible you will see two NESTED LOOPS joins in the operations column of the plan, where you previously only saw one...
select * from hek_test_in a,hek_test_indetail b where a.pid=b.fid; Explain Paln输出; SELECT STATEMENT, GOAL = CHOOSE NESTED LOOPS TABLE ACCESS FULL Object owner=APPS Object name=HEK_TEST_INDETAIL TABLE ACCESS BY INDEX ROWID Object owner=APPS Object name=HEK_TEST_IN ...
select * from hek_test_in a,hek_test_indetail b where a.pid=b.fid; Explain Paln输出; SELECT STATEMENT, GOAL = CHOOSE NESTED LOOPS TABLE ACCESS FULL Object owner=APPS Object name=HEK_TEST_INDETAIL TABLE ACCESS BY INDEX ROWID Object owner=APPS Object name=HEK_TEST_IN ...
C# Syntax: Breaking out of two nested foreach loops C# System.Configuration.ApplicationSettingsBase Mystery C# System.Drawing.Image and System.Drawing.Bitmap + (how to) Explicit Conversion + GetPixel C# System.OutOfMemoryException: 'Out of memory.' C# TCP Listener on External IP address - C...
where e.emp_id in(1, 2); -> Nested loop inner join (cost=1.61 rows=2) (actual time=0.238..0.258 rows=2 loops=1) -> Filter: (e.emp_id in (1,2)) (cost=0.91 rows=2) (actual time=0.218..0.233 rows=2 loops=1) -> Index range scan on e using PRIMARY (cost=0.91 rows=2)...