enq: TX - index contention等待

session 1:

CREATE OR REPLACE PROCEDURE bfw_do_select
IS
begin
for i in 1 .. 100000 loop
insert into wxh_tbd values(SEQUENCE_RDS_ALGORITHM.NEXTVAL,'s');
end loop;
commit;
end;
/

BEGIN
FOR idx IN 1 .. 10 LOOP
Dbms_Job.submit(:job_no,'bfw_do_select;');
END LOOP;
COMMIT;
END;
/

 

session2:

exec bfw_do_select;

>@sess_event

EVENT                          TOTAL_WAITS TIME_WAITED
------------------------------ ----------- -----------
buffer busy waits                    26392        2975
SQL*Net message from client             20        1825
enq: TX - index contention            3403         226
log buffer space                         2          72
events in waitclass Other             7262          42
library cache: mutex X                 213          27
enq: HW - contention                   119          22
enq: SQ - contention                   109           7
latch: cache buffers chains            174           3
log file switch completion               2           2
SQL*Net message to client               21           0
db file sequential read                  3           0

 

以前以為按照序列插入的值，不會存在enq: TX - index contention。

看來索引分裂不僅是 5 5 分裂。9 1 也會分裂。