SLTechnology News&Howtos › Database ›

Insert produces blockage

Shulou Source: shulou.com Published: 2022-06-01 05:45:57 10月03日 Update

Description: insert produces blocking.

1. Set up the test table.

SQL > create table lock1 (id1 int primary key)

Table created.

2. Open 2 sessions and perform insert operations sequentially without submitting.

Session 15:

SQL > select sid from v$mystat where rownum insert into lock1 values (1)

1 row created.

Session 151:

SQL > select sid from v$mystat where rownum insert into lock1 values (1); "= = session 151inserted into the database, resulting in a blocking event.

3, check the wait

SQL > select sid,event,BLOCKING_SESSION from v$session where BLOCKING_SESSION is not null

SID EVENT BLOCKING_SESSION

151151enq: TX-row lock contention 15 "= 151is blocked by 15. An enq: TX-row lock contention wait event is generated.

SQL > select * from v$Lock where sid in (151.151 pencils 21) and type='TX' order by sid

ADDR KADDR SID TY ID1 ID2 LMODE REQUEST CTIME BLOCK

55C69924 55C69964 15 TX 393230 952 60 0 165 1 "= waiting on a ROW.

55C7B03C 55C7B07C 151 TX 524320 892 6 0 104 0

576F9504 576F9530 151TX 393230 952 04 104 "= waiting some other resource held.

By the TX

0-none

1-null (NULL)

2-row-S (SS)

3-row-X (SX)

4-share (S)

5-S/Row-X (SSX)

6-exclusive (X)