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1. #Mysql insert on duplicate key update update#
2. #Mysql insert on duplicate key update code#

#Mysql insert on duplicate key update update#

If the purpose of the UPDATE is a high-volume 'increment', then it may be best to move the counter out of the main table into its own table (together with a minimal PK).

#Mysql insert on duplicate key update code#

Write your code to re-run the entire transaction, as this is usually the Regardless of what prevention measures you take, deadlocks will occur. This speed, alone, helps avoid deadlocks. INSERTing 100 rows in a single statement is typically about 10 times as fast as using 100 1-row INSERTs. If the main transaction eventually rolls back, then the worst that could happen is that you inserted something unused in the normalization table. Again, do them with autocommit=1, not inside of some bigger transaction. Those two statements (not unlike your 2-steps) are designed to efficiently copy multiple items into a normalization table, and do it without "burning" AUTO_INCREMENT ids.

If you are doing "batch normalization", see my tips here. This prevents many possible deadlocks and speeds up the processing. If the purpose of this is "normalization", then perform the the upsert outside the main transaction. The best approach is to minimize the locks. Am I missing anything here or should this solve my issues?Īny approach will lock something. When updating or deleting records while iterating over them, any changes to the primary key or foreign keys could affect the chunk query. This may execute two queries instead of one, but I believe an update matching zero rows is basically a no-op. If the client bypasses this code (never trust the client!) then the worst case is their displayed numbers will be lower than expected. Race conditions are not an issue because the client-side code already includes batching operations, and a given user should therefore only be sending one request of this type at a time.

I have fixed deadlock errors in other parts of the game by avoiding "lect from", "insert ignore" and "insert.on duplicate key update" and this appears to be one of the few, if not the only one left. Right now, it uses insert.on duplicate key update (with the unique key being (date, sender, recipient) and while it works I have noticed that it causes deadlock errors during periods of intense activity. I have a database table that saves activity in the form of "date, sender, recipient, action count", that counts how many interactions one player of the game (which you just lost :p) gives to another on a given day. Mysql> INSERT INTO points (id, accounts_id, value, units) VALUES (150,51,158.You know the feeling when you think you've had the best idea but then realise you might not know what you're talking about? This is one of those moments, and I'm hoping my idea can be confirmed or refuted. | id | accounts_id | name | value | value_old | units | timestamp | type |

Whenever a new row is inserted into a table in case the row causes a duplicate entry in the UNIQUE index or PRIMARY KEY, MySQL will throw an error. Mysql> SELECT * FROM points WHERE id=150 INSERT ON DUPLICATE KEY UPDATE statement is available in MySQL as an extension to the INSERT statement. | points | 1 | fk_points_point_types1_idx | 1 | type | A | 6 | NULL | NULL | | BTREE | | | | points | 1 | fk_points_accounts_id_idx | 1 | accounts_id | A | 2 | NULL | NULL | | BTREE | | | | points | 0 | unique_points2_pk | 2 | accounts_id | A | 27 | NULL | NULL | | BTREE | | | | points | 0 | unique_points2_pk | 1 | id | A | 27 | NULL | NULL | | BTREE | | | | points | 0 | unique_points_pk | 2 | id | A | 27 | NULL | NULL | | BTREE | | | | points | 0 | unique_points_pk | 1 | accounts_id | A | 2 | NULL | NULL | | BTREE | | | Make sure you read the tutorial carefully and try it to understand it properly. It is a very easy process and needs a single statement which is the INSERT ON DUPLICATE KEY UPDATE. | points | 0 | name_UNIQUE | 2 | accounts_id | A | 27 | NULL | NULL | | BTREE | | | By Tejas Gaikwad / OctoIn this tutorial, we will learn how we can handle the duplicate insertion of the record in a MySQL table. | points | 0 | name_UNIQUE | 1 | name | A | 27 | NULL | NULL | | BTREE | | | | points | 0 | PRIMARY | 2 | accounts_id | A | 27 | NULL | NULL | | BTREE | | | | points | 0 | PRIMARY | 1 | id | A | 27 | NULL | NULL | | BTREE | | | | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | | value_old | varchar(45) | YES | | NULL | | | name | varchar(45) | NO | MUL | NULL | | | accounts_id | int(11) | NO | PRI | NULL | | | Field | Type | Null | Key | Default | Extra | Why does the INSERT ON DUPLICATE KEY UPDATE fail? I read that I also need to add a UNIQUE INDEX (but I have no idea why) and did so, but it still fails.