Broken auto_increment on primary key? - mysql

I have no idea how to fix this, I've dumped and recreated the database (per an answer somewhere else), tried manually inserting 128 ... and tried just deleting 127 and tried again. :/ Can't figure it out.
Copied this from the query I just tried:
INSERT INTO `bestofthebest2`.`Topics` (`topicid`, `category`, `topic`)
VALUES ('128', '', ''), (NULL , '', '')
MySQL said: Documentation
#1062 - Duplicate entry '127' for key 'topicid'

Is the data type of topicid a TINYINT by chance? The maximum value a signed tinyint can hold is 127. Additionally, MySQL has a rather odd (in my opinion) overflow behavior in that it simply rounds down overflows rather than erroring. What's happening is that it's trying to increment to 128, but that overflows, so it gets changed to 127. Since 127 already exists, it errors.
This can be easily recreated:
CREATE TABLE test ( id TINYINT AUTO_INCREMENT PRIMARY KEY );
INSERT INTO test (id) VALUES (128);
-- A select will show you a row with id = 127
INSERT INTO test (id) VALUES (128);
-- ERROR 1062 (23000): Duplicate entry '127' for key 'PRIMARY'
The simplest fix is to use a bigger data type. A signed integer will afford you 2^31-1 values, so unless you plan on having more than 2 billionish topics, it should work well:
ALTER TABLE bestofthebest2 CHANGE topicid topicid INT NOT NULL;

First:
SELECT MAX(topicid)+1 FROM `bestofthebest2`.`Topics`;
Then with the result as $RESULT:
ALTER TABLE `bestofthebest2`.`Topics` AUTO_INCREMENT = $RESULT;

Related

Manually updating primary key in a row causes subsequent insert to fail / Duplicate entry for key

I have a table with schema like this:
CREATE TABLE `things` (
`thing_id` INT(11) NOT NULL AUTO_INCREMENT,
`name` VARCHAR(32) NOT NULL DEFAULT '',
PRIMARY KEY (`thing_id`)
) ENGINE=INNODB DEFAULT CHARSET=utf8mb4;
And some sample data:
INSERT INTO things VALUES (NULL, 'thing 1'), (NULL, 'thing 2');
In my application, sometimes I want to bump the primary key of a row to be the highest in the table. For example, I want the thing_id of thing 1 changed to 3 (the table's current autoincrement value). Previously the table was MyISAM and this was accomplished as follows:
UPDATE things t
JOIN (SELECT MAX(thing_id) + 1 AS max_id FROM things) v
SET t.thing_id = v.max_id
WHERE thing_id = 1;
That part still works. However, now with InnoDB, the next insert fails since doing that update leaves the table's autoincrement value still pointing to the same thing. So now if I do an insert now like this:
INSERT INTO things VALUES (NULL, 'thing 3');
I will get an error like:
Duplicate entry '3' for key 'PRIMARY'
This was not an issue with MyISAM. How can I accomplish the same thing using InnoDB without running into this error? My guess is that there's a better way to change the thing_id which will keep the table's autoincrement value intact, but that's where I'm stumped.
And lastly, here's a dbfiddle:
https://www.db-fiddle.com/f/enJPVkwNN6hocjquw38BHD/0
Reference: Innodb Auto Increment Initialization
If you specify an AUTO_INCREMENT column for an InnoDB table, the table handle in the InnoDB data dictionary contains a special counter called the auto-increment counter that is used in assigning new values for the column. This counter is stored only in main memory, not on disk.
Update:
You can reset this counter using below query, works for InnoDB storage engine in MySQL 5.7
ALTER TABLE things AUTO_INCREMENT = 1;
Executing this is resetting auto-increment counter to Max + 1 value.

INSERT ON DUPLICATE updates unrelated row

I currently have a table with 3 columns, ID (primary ai), Key (unique binary(32)), Value (string) and that's it. Key is just the sha256 binary value of Value.
I'm testing my database by doing a lot of prepared batch inserts statements, each with 1-200 values at random. The reason I'm updating Value is incase Value somehow got changed overtime, I always want Value to match the Key hash
INSERT INTO kv (key, value) VALUES (UNHEX(?), ?) ON DUPLICATE KEY UPDATE id=id, value = VALUES(value)
My problem is after inserting a bunch of random data when I look in my database some of my values are getting overwritten and I'm not sure why. A Key of sha256("100") could randomly have a Value of "123". Only a small amount of my data is incorrect, but the fact any of it is incorrect is bothersome.
I've turned on mysqld logging for all sql statements and all of my insert statements show Key: sha256("100") Value: "100" being inserted, never would "123" or any incorrect data appear in logs, but in the database it would be the incorrect value.
My problem is my data doesn't match my statements?
I've tried emptying my database and rerunning all of the statements individually one by one slowly and all of my data stays correct.
I'm not sure what or how I should go about looking for what the problem might be, I tried MariaDB 10.0.26 and 10.1.14 and both times I've run into this issue.
(added from comment:)
CREATE TABLE IF NOT EXISTS ip_raw (
id int(10) unsigned NOT NULL AUTO_INCREMENT,
tokenhash binary(32) NOT NULL,
tokenvalue varchar(45) COLLATE utf8mb4_bin NOT NULL,
PRIMARY KEY (id),
UNIQUE KEY token (tokenhash)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin AUTO_INCREMENT=1 ;

MySQL 5.5.24 - Duplicate entry on UPDATE, when there's no real duplicate

I have to update a table with the following structure:
CREATE TABLE `eav_entity_attribute` (
`entity_attribute_id` int(10) unsigned NOT NULL AUTO_INCREMENT COMMENT 'Entity Attribute Id',
`entity_type_id` smallint(5) unsigned NOT NULL DEFAULT '0' COMMENT 'Entity Type Id',
`attribute_set_id` smallint(5) unsigned NOT NULL DEFAULT '0' COMMENT 'Attribute Set Id',
`attribute_group_id` smallint(5) unsigned NOT NULL DEFAULT '0' COMMENT 'Attribute Group Id',
`attribute_id` smallint(5) unsigned NOT NULL DEFAULT '0' COMMENT 'Attribute Id',
`sort_order` smallint(6) NOT NULL DEFAULT '0' COMMENT 'Sort Order',
PRIMARY KEY (`entity_attribute_id`),
UNIQUE KEY `UNQ_EAV_ENTITY_ATTRIBUTE_ATTRIBUTE_SET_ID_ATTRIBUTE_ID` (`attribute_set_id`,`attribute_id`),
UNIQUE KEY `UNQ_EAV_ENTITY_ATTRIBUTE_ATTRIBUTE_GROUP_ID_ATTRIBUTE_ID` (`attribute_group_id`,`attribute_id`),
KEY `IDX_EAV_ENTITY_ATTRIBUTE_ATTRIBUTE_SET_ID_SORT_ORDER` (`attribute_set_id`,`sort_order`),
KEY `IDX_EAV_ENTITY_ATTRIBUTE_ATTRIBUTE_ID` (`attribute_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='Eav Entity Attributes'
Above table contains a single row:
INSERT INTO `eav_entity_attribute`
(`entity_attribute_id`, `entity_type_id`, `attribute_set_id`, `attribute_group_id`, `attribute_id`, `sort_order`)
VALUES
(32758, 4, 224, 3423, 5171, 12)
I'm running an automatic import procedure, which will read an external source of data and write into this table.
This import runs multiple times and, therefore, sometimes the same data is imported several times. In such case, the procedure simply overwrites the old data with the new one, even when the new one is identical to the old. The condition where the same data exists is handled with an ON DUPLICATE KEY UPDATE clause. This works almost perfectly, except on this specific table.
On this table, when the procedure attempts an UPDATE, I receive a "Duplicate key" message, which I can't explain. I debugged the code, and this is the query that fails (extracted from the INSERT..ON DUPLICATE KEY):
UPDATE eav_entity_attribute
SET
`attribute_group_id` = 3423
,`attribute_id` = 5171
,`attribute_set_id` = 223
,`entity_type_id` = 4
,`sort_order` = 320
WHERE
(`attribute_group_id` = 3423) AND
(`attribute_id` = 5171)
The error is the following:
Error Code: 1062. Duplicate entry '3423-5171' for key 'UNQ_EAV_ENTITY_ATTRIBUTE_ATTRIBUTE_GROUP_ID_ATTRIBUTE_ID'
I know that the pair 3423-5171 already exists, but the UPDATE would replace these values with themselves, not create a new entry. I'm quite confused about the cause of this issue, any suggestion would be very welcome. Thanks.
Update - New finding
I got some sort of "inspiration" and I made an experiment. I removed the Unique constraint involving on (attribute_set_id,attribute_id) (note, this is not the one in the error) and I ran the INSERT..ON DUPLICATE query. It worked perfectly.
Mine is a conjecture, but this is what I think: the data I'm trying to write to the table clashes with two constraints:
UNIQUE(attribute_set_id,attribute_id)
UNIQUE(attribute_group_id,attribute_id)
The INSERT fails, presumably because of the duplication error raised by the first constraint. This triggers the UPDATE, which uses the first constraint as the implicit WHERE clause. My speculation is that, in such case, the first constraint is somehow ignored, but the UPDATE trips over the second, which didn't get involved earlier.
This still doesn't seem, to me, a valid reason for an UPDATE which replaces something with itself to raise a duplicate entry error, but it may shed some light on the logic behind it.
Second Update
I found out that the table I was testing against actually contains a lot of rows (I forgot to disable the filtered view) resulting from the successful import of other data. However, the "duplicate candidate" is still unique in the set.
I confirm what posted in the comments, when the table contains only that rows, the INSERT..ON DUPLICATE works, as well as the UPDATE alone. Now I'm wondering why does the table get messed up when there is more data in it, since we are still talking about a single unique row being updated with the same data.
Third Update - Found the root cause
I finally found out the reason why the UPDATE fails, now I have to find out how do I get in such condition.
The clue was my conjecture in the first update. Simply, I have two very similar rows (please note I'm using different values as I started from a clean database).
row,entity_attribute_id,entity_type_id,attribute_set_id,attribute_group_id,attribute_id,sort_order
1,16919, 4, 120, 1746, 80, 1
2,16649, 4, 119, 1744, 80, 210
Here's what happens:
The INSERT attempts to insert a row with the following values: 120, 4, 1744, 80, 54.
This triggers the "duplicate key", since the values 120, 80 are a duplicate for the fields attribute_set_id, attribute_id (row 1).
MySQL then tries the UPDATE, which becomes as follows:
UPDATE table
entity_type_id = 4
,attribute_group_id = 1744
,sort_order = 54
WHERE
(attribute_set_id = 120) AND (attribute_id = 80)
This time, the UPDATE fails because the values 1744,80 are violate the constraint on the pair attribute_group_id, attribute_id, found in row 2.
In summary
The INSERT fails because row 1 has the same values for the key attribute_set_id, attribute_id.
The UPDATE fails because row 2 has the same values for the key attribute_group_id, attribute_id.
Solution
I will have to review the whole import procedure, as, in theory, none of such duplicates should arise. MySQL is doing its job fine, it's the database that is complicated.
Thanks for all the suggestions.
Try not to update key values within UPDATE clause of INSERT ... ON DUPLICATE KEY UPDATE. It is strange to ask MySQL to change key values if a record with these key values already exist, so, unexpected behavoiur of MySQL is not surprising.

MySQL Auto-Inc Bug?

In my MySQL table I've created an ID column which I'm hoping to auto-increment in order for it to be the primary key.
I've created my table:
CREATE TABLE `test` (
`id` INT( 11 ) NOT NULL AUTO_INCREMENT PRIMARY KEY ,
`name` VARCHAR( 50 ) NOT NULL ,
`date_modified` DATETIME NOT NULL ,
UNIQUE (
`name`
)
) TYPE = INNODB;
then Inserted my records:
INSERT INTO `test` ( `id` , `name` , `date_modified` )
VALUES (
NULL , 'TIM', '2011-11-16 12:36:30'
), (
NULL , 'FRED', '2011-11-16 12:36:30'
);
I'm expecting that my ID's for the above are 1 and 2 (respectively). And so far this is true.
However when I do something like this:
insert into test (name) values ('FRED')
on duplicate key update date_modified=now();
then insert a new record, I'm expecting it to be 3, however now I'm shown an ID of 4; skipping the place spot for 3.
Normally this wouldn't be an issue but I'm using millions of records which have thousands of updates every day.. and I don't really want to even have to think about running out of ID's simply because I'm skipping a ton of numbers..
Anyclue to why this is happening?
MySQL version: 5.1.44
Thank you
My guess is that the INSERT itself kicks off the code that generates the next ID number. When the duplicate key is detected, and ON DUPLICATE KEY UPDATE is executed, the ID number is abandoned. (No SQL dbms guarantees that automatic sequences will be without gaps, AFAIK.)
MySQL docs say
In general, you should try to avoid using an ON DUPLICATE KEY UPDATE
clause on tables with multiple unique indexes.
That page also says
If a table contains an AUTO_INCREMENT column and INSERT ... ON
DUPLICATE KEY UPDATE inserts or updates a row, the LAST_INSERT_ID()
function returns the AUTO_INCREMENT value.
which stops far short of describing the internal behavior I guessed at above.
Can't test here; will try later.
Is it possible to change your key to unsigned bigint - 18,446,744,073,709,551,615 is a lot of records - thus delaying the running out of ID's
Found this in mysql manual http://dev.mysql.com/doc/refman/5.1/en/example-auto-increment.html
Use a large enough integer data type for the AUTO_INCREMENT column to hold the
maximum sequence value you will need. When the column reaches the upper limit of
the data type, the next attempt to generate a sequence number fails. For example,
if you use TINYINT, the maximum permissible sequence number is 127.
For TINYINT UNSIGNED, the maximum is 255.
More reading here http://dev.mysql.com/doc/refman/5.6/en/information-functions.html#function_last-insert-id it could be inferred that the insert to a transactional table is a rollback so the manual says "LAST_INSERT_ID() is not restored to that before the transaction"
What about for a possible solution to use a table to generate the ID's and then insert into your main table as the PK using LAST_INSERT_ID();
From the manual:
Create a table to hold the sequence counter and initialize it:
mysql> CREATE TABLE sequence (id INT NOT NULL);
mysql> INSERT INTO sequence VALUES (0);
Use the table to generate sequence numbers like this:
mysql> UPDATE sequence SET id=LAST_INSERT_ID(id+1);
mysql> SELECT LAST_INSERT_ID();
The UPDATE statement increments the sequence counter and causes the next call to
LAST_INSERT_ID() to return the updated value. The SELECT statement retrieves that
value. The mysql_insert_id() C API function can also be used to get the value.
See Section 20.9.3.37, “mysql_insert_id()”.
It's really a bug how you can see here: http://bugs.mysql.com/bug.php?id=26316
But, apparently, they fixed it on 5.1.47 and it was declared as INNODB plugin problem.
A duplicate, but same problem, you can see here too: http://bugs.mysql.com/bug.php?id=53791 referenced to the first page mentioned here in this answer.

MySQL: Insert on duplicate update problem with primary key

I'm running the following query... the issue I'm running into is that it saves the id field properly with rows 0-27 but then it tries to duplicate row 0. Any thoughts on why this is trying to duplicate row 0?
INSERT INTO
deal (`id`, `site_id`)
VALUES (NULL, 1)
ON DUPLICATE KEY UPDATE `id` = NULL,`site_id` = 1
From the manual:
You can also explicitly assign NULL or 0 to the column to generate sequence numbers.
So, effectivly, entering (0,'whatever') is seen as ('the next autoincrement id','whatever'). No duplicate key issues as far as MySQL is concerned. You can bypass this by using NO_AUTO_VALUE_ON_ZERO. Note that using 0 as an identifier is not recommended practice.
A PRIMARY KEY can't be NULL in MySQL, so your UPDATE id = NULL is casted to UPDATE id = 0.
See also: http://www.xaprb.com/blog/2009/09/12/the-difference-between-a-unique-index-and-primary-key-in-mysql/