The INSERT INTO SELECT statement uses the append keyword and the enable_parallel_dml parameter as hints to enable bypass import.
Limitations
- Only parallel data manipulation language (PDML) data can be imported in bypass mode.
- You cannot execute two statements to write the same table at a time because a lock is added to the table during import.
- The
INSERT INTO SELECTstatement cannot be used in triggers. - The
INSERT INTO SELECTstatement supports loading LOBs but the loading performance is poor. Therefore, LOBs are still loaded to the corresponding paths by using transactions. - The
INSERT INTO SELECTstatement cannot be executed in a multi-row transaction.
Syntax
INSERT /*+ append enable_parallel_dml parallel(N) */ INTO table_name select_sentence
For more information about the syntax of the INSERT INTO statement, see INSERT (MySQL mode) and INSERT (Oracle mode).
The parameters are described as follows:
| Parameter | Description |
|---|---|
| append | Specifies to use bypass import. |
| enable_parallel_dml parallel(N) | The degree of parallelism (DOP) for loading data. The default value of N is 4.
NoteGenerally, the |
Examples
Import part of the data in the tbl2 table to the tbl1 table in bypass mode.
obclient [test]> SELECT * FROM tbl1;
Empty set
obclient [test]> SELECT * FROM tbl2;
+------+------+------+
| col1 | col2 | col3 |
+------+------+------+
| 1 | a1 | 11 |
| 2 | a2 | 22 |
| 3 | a3 | 33 |
+------+------+------+
3 rows in set
obclient [test]> INSERT /*+ append enable_parallel_dml parallel(16) */ INTO tbl1 SELECT t2.col1,t2.col3 FROM tbl2 t2;
Query OK, 3 rows affected
Records: 3 Duplicates: 0 Warnings: 0
obclient [test]> SELECT * FROM tbl1;
+------+------+
| col1 | col2 |
+------+------+
| 1 | 11 |
| 2 | 22 |
| 3 | 33 |
+------+------+
3 rows in set
In the Note section of the result of the EXPLAIN EXTENDED statement, check whether the data is written through bypass import.
obclient [test]> EXPLAIN EXTENDED INSERT /*+ append enable_parallel_dml parallel(16) */ INTO tbl1 SELECT t2.col1,t2.col3 FROM tbl2 t2;
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Query Plan |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| =========================================================================== |
| |ID|OPERATOR |NAME |EST.ROWS|EST.TIME(us)| |
| --------------------------------------------------------------------------- |
| |0 |OPTIMIZER STATS MERGE | |3 |27 | |
| |1 | PX COORDINATOR | |3 |27 | |
| |2 | EXCHANGE OUT DISTR |:EX10001 |3 |27 | |
| |3 | INSERT | |3 |26 | |
| |4 | EXCHANGE IN DISTR | |3 |1 | |
| |5 | EXCHANGE OUT DISTR (RANDOM)|:EX10000 |3 |1 | |
| |6 | OPTIMIZER STATS GATHER | |3 |1 | |
| |7 | SUBPLAN SCAN |ANONYMOUS_VIEW1|3 |1 | |
| |8 | PX BLOCK ITERATOR | |3 |1 | |
| |9 | TABLE SCAN |t2 |3 |1 | |
| =========================================================================== |
| Outputs & filters: |
| ------------------------------------- |
| 0 - output(nil), filter(nil), rowset=256 |
| 1 - output([column_conv(INT,PS:(11,0),NULL,ANONYMOUS_VIEW1.col1(0x7f0ba6a51800))(0x7f0ba6a522c0)], [column_conv(INT,PS:(11,0),NULL,ANONYMOUS_VIEW1.col3(0x7f0ba6a51ac0))(0x7f0ba6a59630)]), |
| filter(nil), rowset=256 |
| 2 - output([column_conv(INT,PS:(11,0),NULL,ANONYMOUS_VIEW1.col1(0x7f0ba6a51800))(0x7f0ba6a522c0)], [column_conv(INT,PS:(11,0),NULL,ANONYMOUS_VIEW1.col3(0x7f0ba6a51ac0))(0x7f0ba6a59630)]), |
| filter(nil), rowset=256 |
| dop=16 |
| 3 - output([column_conv(INT,PS:(11,0),NULL,ANONYMOUS_VIEW1.col1(0x7f0ba6a51800))(0x7f0ba6a522c0)], [column_conv(INT,PS:(11,0),NULL,ANONYMOUS_VIEW1.col3(0x7f0ba6a51ac0))(0x7f0ba6a59630)]), |
| filter(nil) |
| columns([{tbl1: ({tbl1: (tbl1.__pk_increment(0x7f0ba6a51d80), tbl1.col1(0x7f0ba6a30a90), tbl1.col2(0x7f0ba6a30d50))})}]), partitions(p0), |
| column_values([T_HIDDEN_PK(0x7f0ba6a52040)], [column_conv(INT,PS:(11,0),NULL,ANONYMOUS_VIEW1.col1(0x7f0ba6a51800))(0x7f0ba6a522c0)], [column_conv(INT,PS:(11,0),NULL,ANONYMOUS_VIEW1.col3(0x7f0ba6a51ac0))(0x7f0ba6a59630)]) |
| 4 - output([column_conv(INT,PS:(11,0),NULL,ANONYMOUS_VIEW1.col1(0x7f0ba6a51800))(0x7f0ba6a522c0)], [column_conv(INT,PS:(11,0),NULL,ANONYMOUS_VIEW1.col3(0x7f0ba6a51ac0))(0x7f0ba6a59630)], |
| [T_HIDDEN_PK(0x7f0ba6a52040)]), filter(nil), rowset=256 |
| 5 - output([column_conv(INT,PS:(11,0),NULL,ANONYMOUS_VIEW1.col1(0x7f0ba6a51800))(0x7f0ba6a522c0)], [column_conv(INT,PS:(11,0),NULL,ANONYMOUS_VIEW1.col3(0x7f0ba6a51ac0))(0x7f0ba6a59630)], |
| [T_HIDDEN_PK(0x7f0ba6a52040)]), filter(nil), rowset=256 |
| dop=16 |
| 6 - output([column_conv(INT,PS:(11,0),NULL,ANONYMOUS_VIEW1.col1(0x7f0ba6a51800))(0x7f0ba6a522c0)], [column_conv(INT,PS:(11,0),NULL,ANONYMOUS_VIEW1.col3(0x7f0ba6a51ac0))(0x7f0ba6a59630)]), |
| filter(nil), rowset=256 |
| 7 - output([ANONYMOUS_VIEW1.col1(0x7f0ba6a51800)], [ANONYMOUS_VIEW1.col3(0x7f0ba6a51ac0)]), filter(nil), rowset=256 |
| access([ANONYMOUS_VIEW1.col1(0x7f0ba6a51800)], [ANONYMOUS_VIEW1.col3(0x7f0ba6a51ac0)]) |
| 8 - output([t2.col1(0x7f0ba6a50d40)], [t2.col3(0x7f0ba6a512f0)]), filter(nil), rowset=256 |
| 9 - output([t2.col1(0x7f0ba6a50d40)], [t2.col3(0x7f0ba6a512f0)]), filter(nil), rowset=256 |
| access([t2.col1(0x7f0ba6a50d40)], [t2.col3(0x7f0ba6a512f0)]), partitions(p0) |
| is_index_back=false, is_global_index=false, |
| range_key([t2.__pk_increment(0x7f0ba6a6ccf0)]), range(MIN ; MAX)always true |
| Used Hint: |
| ------------------------------------- |
| /*+ |
| |
| USE_PLAN_CACHE( NONE ) |
| PARALLEL(16) |
| ENABLE_PARALLEL_DML |
| APPEND |
| APPEND |
| */ |
| Qb name trace: |
| ------------------------------------- |
| stmt_id:0, stmt_type:T_EXPLAIN |
| stmt_id:1, INS$1 |
| stmt_id:2, SEL$1 |
| Outline Data: |
| ------------------------------------- |
| /*+ |
| BEGIN_OUTLINE_DATA |
| FULL(@"SEL$1" "test"."t2"@"SEL$1") |
| USE_PLAN_CACHE( NONE ) |
| PARALLEL(16) |
| ENABLE_PARALLEL_DML |
| OPTIMIZER_FEATURES_ENABLE('4.0.0.0') |
| APPEND |
| APPEND |
| END_OUTLINE_DATA |
| */ |
| Optimization Info: |
| ------------------------------------- |
| t2: |
| table_rows:3 |
| physical_range_rows:3 |
| logical_range_rows:3 |
| index_back_rows:0 |
| output_rows:3 |
| est_method:local_storage |
| optimization_method:cost_based |
| avaiable_index_name:[tbl2] |
| table_id:500004:estimation info:(table_type:12, version:-1--1--1, logical_rc:3, physical_rc:3)] |
| stats version:0 |
| Plan Type: |
| DISTRIBUTED |
| Note: |
| Degree of Parallelism is 16 because of hint |
| Direct-mode is enabled in insert into select |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
86 rows in set
