LevelDB storage engine (MDEV-3841)

[MDEV-4196] LevelDB: Autoincrement is not increased on inserting an explicit value Created: 2013-02-22  Updated: 2013-05-27  Resolved: 2013-05-27

Status: Closed
Project: MariaDB Server
Component/s: None
Affects Version/s: None
Fix Version/s: 10.1.0

Type: Technical task Priority: Minor
Reporter: Elena Stepanova Assignee: Sergei Petrunia
Resolution: Won't Fix Votes: 0
Labels: leveldb

Issue Links:
Relates

 Description   

If an explicit value (bigger than existing values) is inserted into an auto-increment column of a LevelDB table, the AUTO_INCREMENT doesn't get increased, so the next attempt to use it causes a duplicate key error.

With InnoDB it works as expected (the value grows).

mysql> create table t1 (pk int auto_increment primary key) engine=LevelDB;
 
Query OK, 0 rows affected (0.03 sec)
 
 
 
mysql> insert into t1 values (null);
 
Query OK, 1 row affected (0.00 sec)
 
 
 
mysql> insert into t1 values (2);
 
Query OK, 1 row affected (0.00 sec)
 
 
 
mysql> show create table t1;
 
+-------+-------------------------------------------------------------------------------------------------------------------------------------------+
 
| Table | Create Table                                                                                                                              |
 
+-------+-------------------------------------------------------------------------------------------------------------------------------------------+
 
| t1    | CREATE TABLE `t1` (
 
  `pk` int(11) NOT NULL AUTO_INCREMENT,
 
  PRIMARY KEY (`pk`)
 
) ENGINE=LEVELDB AUTO_INCREMENT=2 DEFAULT CHARSET=latin1 |
 
+-------+-------------------------------------------------------------------------------------------------------------------------------------------+
 
1 row in set (0.00 sec)
 
 
 
mysql> insert into t1 values (null);
 
ERROR 1062 (23000): Duplicate entry '2' for key 'PRIMARY'
 
mysql> 

revision-id: psergey@askmonty.org-20130208190127-uq98t2n3jl85c50r
 
revno: 4595
 
branch-nick: mysql-5.6-leveldb

Test case:

create table t1 (pk int auto_increment primary key) engine=LevelDB;
 
insert into t1 values (null);
 
show create table t1;
 
insert into t1 values (2);
 
show create table t1;
 
insert into t1 values (null);

Also covered in leveldb.autoincrement test, only there it causes a result mismatch rather than ER_DUP_ENTRY because the test uses a non-unique index for the column.



 Comments   
Comment by Sergei Petrunia [ 2013-05-15 ]

Debugging the statement

insert into t1 values (2);

I find that execution reaches this function

void handler::adjust_next_insert_id_after_explicit_value(ulonglong nr)
{
/*
If we have set THD::next_insert_id previously and plan to insert an
explicitely-specified value larger than this, we need to increase
THD::next_insert_id to be greater than the explicit value.
*/
if ((next_insert_id > 0) && (nr >= next_insert_id))
set_next_insert_id(compute_next_insert_id(nr, &table->in_use->variables));
}

and there, nr=<2, or whatever I have specified>, next_insert_id=0.

Since next_insert_id==0, the value is not updated.

Comment by Sergei Petrunia [ 2013-05-15 ]

The above might be ok actually. I'll need to debug auto_increment code further to find out.

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