During direct-path INSERT, the database obtains exclusive locks on the table (or
on all partitions of a partitioned table). As a result, users cannot perform any
concurrent insert, update, or delete operations on the table, and concurrent
index creation and build operations are not permitted. Concurrent queries,
however, are supported, but the query will return only the information before
the insert operation.
The
behaviour of /*+ APPEND */ hint has changed in the different versions of
Oracle:
- In Oracle 10g and previous releases the APPEND hint is ignored when
specifying INSERT..VALUES. Thus even though stated, the insert will be done in
conventional mode and not use direct-path insert into the buffer cache. When
using INSERT..SELECT the hint will be honoured.
- On 11g Release 1, the APPEND hint will be honoured for an INSERT with VALUES
and the row will be inserted directly into datafiles, bypassing the buffer
cache.
- In 11g release 2, a new hint has been added, /*+ APPEND_VALUES */ that will
load the data directly into the datafiles.
To
summarize, there are now 2 different hints for direct-path load:
- APPEND: Instructs Oracle to use direct-path INSERT with the subquery syntax
of the INSERT statement.
- APPEND_VALUES: Instructs Oracle to use direct-path INSERT with the VALUES
clause.
INSERT .. VALUES and APPEND
HINT
Version:
10.2.0.4
--SID=159:
SQL> create table test_insert (id number, name varchar2(25));
SQL> insert /*+ APPEND */ into test_insert values (1,'Test1');
1 row created.
select sid,type,id1,id2,lmode from v$lock where sid=159;
SQL>
SID TY ID1 ID2 LMODE
---------- -- ---------- ---------- ----------
159 TM 61245 0 3
159 TX 262153 3571 6
APPEND
hint ignored and lock mode=3 Row Exclusive Version:
11.1.0.7
--SID=131:
SQL> create table test_insert (id number, name varchar2(25));
SQL> insert /*+ APPEND */ into test_insert values (1,'Test1');
1 row created.
select sid,type,id1,id2,lmode from v$lock where sid=131;
SQL>
SID TY ID1 ID2 LMODE
---------- -- ---------- ---------- ----------
131 TM 84239 0 6
131 TX 65548 4981 6
APPEND
hint honoured and lock mode=6 Exclusive
Version:
11.2.0.3
--SID=59
SQL> create table test_insert (id number, name varchar2(25));
SQL> insert /*+ APPEND */ into test_insert values (1,'Test1');
1 row created.
select sid,type,id1,id2,lmode from v$lock where sid=59;
SID TY ID1 ID2 LMODE
---------- -- ---------- ---------- ----------
69 TM 96843 0 3
69 TX 196640 3301 6
APPEND
hint ignored and lock mode=3 Row Exclusive INSERT
.. VALUES and APPEND_VALUES HINTVersion:
11.2.0.3
--SID=134
SQL> create table test_insert (id number, name varchar2(25));
SQL> insert /*+ APPEND_VALUES */ into test_insert values (1,'Test1');
1 row created.
SQL> select sid,type,id1,id2,lmode from v$lock where sid=134;
SID TY ID1 ID2 LMODE
---------- -- ---------- ---------- ----------
134 TM 96843 0 6
134 TX 65565 7849 6
New
APPEND_VALUES hint honoured and lock mode=6 Exclusive INSERT .. SELECT and APPEND HINT
All
Versions
--SID=77
SQL> insert /*+ APPEND */ into test_insert select object_id,object_name from user_objects;
59 rows created.
SQL> select sid,type,id1,id2,lmode from v$lock where sid=77;
SID TY ID1 ID2 LMODE
---------- -- ---------- ---------- ----------
77 TM 96843 0 6
77 TX 589827 8029 6
APPEND
hint honoured and lock mode=6 Exclusive
阅读(1011) | 评论(0) | 转发(0) |