Mysql uuid primary key performance Don’t! Apr 1, 2024 · CREATE TABLE Users (id UUID PRIMARY KEY, name VARCHAR(50), email VARCHAR(100)); In this schema, the ‘id’ column is defined as a UUID primary key. Not even TINYTEXT. Dec 19, 2014 · But here comes the problem, using it as PRIMARY KEY causes the problems described below. To boost reading performance for all UUID I have this plan to put an index on every UUID column. UUID를 Primary Key로 사용하는 것은 이점이 많습니다. Jun 2, 2024 · Summary. Nov 19, 2010 · CREATE TABLE users ( id VARCHAR(36) PRIMARY KEY DEFAULT UUID() ) But it still has a downside: It occupies a lot of storage. Either unique key is sufficient for InnoDB's requirement of having a PRIMARY KEY. Problems with UUID. Dec 23, 2022 · UUID v1. When done right, such a composite primary key should result in: Jan 5, 2009 · a CHAR and a BINARY field are essentially the same. PRIMARY KEY: Makes the "id" column the primary key, ensuring unique values for each row. A well-designed multi-column primary key can yield even better performance than a UUID primary key, but it requires more up-front schema design work. It’s the most prevalent and widely supported UUID standard, even the example UUID given above is a UUIDv4. UUIDs might sort slower. Relational databases have been around for almost 50 years. 구조상 중복 발생 확률이 매우 적으며(약 수백조 분의 일 확률), 길이는 일정하고 알파벳과 숫자로만 이루어져 있어 다루기도 쉽죠. CREATE TABLE my_table ( );: This line creates a new table named "my_table". While UUIDs offer benefits in certain scenarios, there are reasons why they might not be the best choice for a primary key: Indexing and Performance: UUIDs are 128 bits long, compared to 32 bits for a typical integer. By understanding the application scenarios, optimizing index structures, and considering hybrid approaches, developers can make informed decisions to enhance database performance. So i was thinking of adding an additional column called uuid which i could use to retrieve files. Sep 21, 2021 · The first thing I noticed is that their main table had a poor definition of the Primary Key as they were using UUID-like columns based on VARCHAR data types. Apr 30, 2023 · The negative impact of using UUID as the primary key comes from how MySQL’s default engine, InnoDB, stores the data. There is always a PRIMARY KEY: an explicit PK, or; the first UNIQUE key with non-null column(s), or; a fabricated, hidden, 6-byte PK. First of all, I was wondering: would UUIDs be less performant as a primary key? Jan 8, 2024 · Now, let’s go through the advantages and disadvantages of using UUID as the primary key. As ypercube mentioned towards end of answer, InnoDB uses a clustered key structure, and the key used for clustering is the PRIMARY KEY. In fact, a few years ago, I looked into setting up a database cluster, and back then, the hurdle I Dec 28, 2020 · Usar UUID como tipo numa PK (Primary Key) em vez de Int/BigInt em bancos de dados relacionais (RDBMS) parece ter se tornado comum em aplicações nesse mundo de APIs REST, microsserviços e sistemas distribuídos, afinal temos algumas boas vantagens nessa abordagem: May 20, 2009 · When the app goes online, I need to synchronize its database with the central db, and to avoid conflicts and to be able to use a synchronization tool I found, the simplest way is to use a UUID as primary key in each table. I don't have a recent enough version of MySQL at hand to test this. This example generates a single UUID, which can be used as a unique identifier for data entries. Advantages: UUIDs are a good alternative to AUTO_INCREMENT PRIMARY KEY and are used mainly because: May 22, 2017 · Generating the UUID on the client distributes the extra work (not much extra work) away from the server. Sep 14, 2024 · In MySQL, the auto-increment feature allows you to generate sequential values for a column (often the primary key) automatically. TableAMap. In this article, you'll learn about the downsides of using UUIDs as a primary key in your MySQL database. Mar 5, 2023 · I have used UUID (or GUID) for my identifications. If you insert a new value into a random place in the middle of a B-tree, it may have to split the B-tree nonterminal node, and that could cause the node at the next higher level to split, and so on up to the top of the B-tree. using a custom UUID that has nice sequential properties vs. Stats below have been As PK it want to use an UUID instead of the auto increment bigint to avoid collisions You won't have collisions with auto_increment/identity. Jul 16, 2024 · Query Performance: Binary UUIDs are more efficient for comparison operations, as they involve fewer bytes. ID, and TableAMap. It was mentioned before that primary key values should be inserted in a chronological order. They will make your indexes larger than if you use a bigint though. UUIDs are 128-bit numbers that can be generated independently across different systems without the risk of duplication. Tables inside the database must have a primary key column that is both unique and not nullable. 3. – Dec 25, 2024 · 현재 재직중인 회사에서는 mysql을 메인 rdb로 사용하며, 대부분의 테이블에서 uuid(v4)를 pk로 채택하여 사용하고 있다. I'm wondering what is better for performance and everything else when we use mysql db. If your UUID is the PK, then you are doing splits/fragmentation on the data. Use a 1:1 translation table for slug-to-internal index, a "key translation table" or "domain adapter for primary keys" (here from the web domain to your internal data model domain). Why it is a problem A 'standard' GUID/UUID is composed of the time, machine identification and some other stuff. What Exactly is a UUID? […] Apr 2, 2021 · I'm at a crossroads where I need to decide if I'm going to stick with bigserial as my primary key, or change to uuid (non-auto-generating—my API server will generate the ID using uuid v4 and insert it). Performance with the SequentialAsBinary method was also similar, probably due to the fact that, even with incorrect byte order, the values are "sort of Feb 12, 2017 · It is probable that there are similar solutions for other databases, certainly PostgreSQL, MySQL and likely the rest. 000 rows are created. Earlier this year, we made the decision to use UUIDv7 as the primary key for all new tables (instead of sequential integer IDs). INSERT INTO users (id, username) VALUES (UUID(), 'johndoe'); Here, a new user is added to the `users` table with a UUID as the `id`, ensuring each user has a unique identifier. The ultimate thing is that the pages are ordered by the primary key. At first, everything was as expected, high IO wait due to heavy writing; however, after a few million records a trend started to appear: when records were being inserted into innodb_uuid the high IO wait persisted but the heavy writing was replaced with very heavy reading and much lower writing. CREATE TABLE OrderDetails(OrderId BINARY(16) PRIMARY KEY, ProductName VARCHAR(100) NOT NULL, It's a matter of choice actually and this question can raise opinion based answers from my point of view. Sep 1, 2017 · I immediately realized the auto-incrementing int primary keys in the MySql database would be an issue, and thought about using GUID/UUID primary keys instead. JOIN performance: Keys not of INT data type lead to 60-70% worse join performance. Your bottlenecks will be somewhere else, almost guaranteed. ID is the same as TableA. I find that there is no AUTOINCREMENT in Postgresql, only SEQUENCE or UUID. Feb 16, 2022 · When people say UUID they’re almost always referring to UUIDv4. Apr 26, 2011 · So read the following chapter from High performance MySQL 2ed, Yes, I'm using InnoDB some of the apps in the company I work for uses UUID as primary key, but I Sep 22, 2015 · Update: MySQL 8. UUIDの特性: UUIDは時間とランダム性に基づいて生成されるため、無作為に分布します。このため、インデックス構造上、データがB-Treeに挿入される際に、データが Jan 2, 2018 · I chose to update my application and database to use UUIDs as primary key. Mar 2, 2015 · I have a UUID string that I want to use as my MySQL tables primary key, the UUID is a 32 character hexadecimal string (after '-' characters are stripped). 0 has a builtin function for such. InnoDB by default creates a b-tree for the table’s primary key and stores the rows data in the leaf nodes of the same b-tree which is called a clustered index. The one that MySQL implements in the UUID() function is version 1 which is composed of the timestamp, UUID version and MAC address. Because it's a string, UUID keys may have a performance and storage hit. And like he said it is easilly solved by adding meaningfull unique constraints to non-key columns. This thread . Having a non-sequential GUID Clustered Index is the issue. I have two questions: What is the best way to store a UUID field in MySql? CHAR(36)? As far as I can see, MySql doesn't have a dedicated UUID data type? Sep 3, 2023 · PostgreSQL Primary Key Dilemma: UUID vs. This has the added advantage of masking other user's id (as I want to build APIs that take Oct 23, 2023 · 現時点でRDBのprimary keyには何を使用するのがいいのかを自分なりに考えた備忘録です。 候補は以下になります。 AUTO_INCREMENT; UUID V4; ULID; UUID V7(Draft状態) 1つずつメリット・デメリットを見ていこうと思います。 AUTO_INCREMENT Jan 13, 2024 · We are building an app from scratch and one developer is using uuid type string for primary key and I used integer with auto increment. If your UUIDs are being stored as strings they are likely to sort much slower than auto-incrementing IDs. Nov 14, 2020 · Here's an example where a table users uses binary UUIDs for its primary key: CREATE TABLE users ( id BINARY (16) NOT NULL, name VARCHAR (255) NOT NULL, PRIMARY KEY (id) ); INSERT INTO users (id, name) VALUES (uuid_to_bin(uuid()), 'Larry Page') , (uuid_to_bin(uuid()), 'Sergey Brin'); SELECT bin_to_uuid(id) AS id , name FROM users; Aug 16, 2018 · Benchmarking the performance of using various UUID types as the primary key on database tables instead of an auto-incrementing integer. Performance degradation can range from few percent to couple of times for Innodb tables 3. explains how to generate UUIDs on insert. See full list on percona. The RFC4122 specifies 5 versions. It is fast. I've spent hours researching bigserial vs uuid primary keys, and it seems no one can agree on what the disadvantages of uuid would be Aug 16, 2024 · Optimization #1: Non-Clustered Primary Key. 0: MySQL supports descending indexes: DESC in an index definition is no longer ignored but causes storage of key values in descending order. Jan 8, 2024 · When designing a database, choosing the appropriate primary key format is critical to the system’s performance, scalability, and data integrity. Although there is an insert performance footprint, I believe the overall benefits of this approach outweigh the drawbacks in this context. 1. used only for "direct access Feb 14, 2019 · When a primary key is not defined on a table, MySQL generates row-ids for every row that is Importance of Primary Keys in MySQL Performance; UUID vs. Mar 19, 2024 · You might think that using UUIDs as a primary key in a database is a great idea, but when used incorrectly, they can drastically hurt database performance. ; VARCHAR (etc) are not allowed beyond some size (depends on version and CHARACTER SET). com Nov 10, 2024 · To give you an example, if you are connecting tables that have UUIDs as primary keys, the join process will need more calculation than it would if the keys were plain numbers. Jan 18, 2021 · Creating a UUID Primary Key Using uuid-osp - PostgreSQL Example; Alternative to UUID - Auto-Increment Primary Key; UUID vs Auto-Increment Primary Key; Understanding Keys in SQL . May 18, 2014 · From my point of view, using UUID as primary key in MySQL is bad idea, if we speak about large databases (and large amount of inserts). This is a requirement for InnoDB. Regular monitoring and adjustments I am currently working on a project with a table with UUID as primary key (in postgresql). MySQL offers a function called UUID() which returns a version 1 UUID as a 36-character string (including hyphens): SELECT UUID(); Jan 17, 2024 · MySQLでプライマリキーをUUIDにする前に知っておいて欲しいこと：UUID(v1)でも順序を担保した保存方法を紹介されています。 MySQLとPostgreSQLと主キー：UUIDをchar(32), binary(16)で保存したケースをベンチマークで比較されています。 MySQLでもULIDを発行した〜い！ Feb 9, 2025 · In this article, we’ll explore how using UUIDs as a Primary Key in MySQL can impact database performance. Use an auto-incrementing primary key as the physical primary key and a UUID as the logical primary key. 0 with the advent of the following function: UUID_TO_BIN(str, swap_flag). Apr 3, 2015 · A Primary Key serves multiple purposes in InnoDB: Ensures uniqueness between rows; InnoDB saves row data on disk clustered by the Primary Key; Depending on the type used and INSERT / UPDATE pattern used, either provides for a unfragmented or severely fragmented Primary Key; I wanted to profile three different Primary Key types: Apr 12, 2023 · UUID primary key performance. incremental ID insert performance in MySQL Apr 22, 2020 · create table tbl_test ( guid binary(16) default (uuid_to_bin(uuid())) not null primary key, name varchar(50) not null ); This is pretty much copied from the documentation. As I'm trying to achieve this with as few changes to my application as possible, I thought about using mysql triggers. Creating trigger in mysql for generation UUID. I'd say stick with INT or BIGINT. I know that a uuid is bad for performance This is not universally true, at least for MSSQL. Jun 2, 2012 · However, performance with the SequentialAsString method was almost identical to an integer primary key, which is what we'd expect since GUIDs are typically stored as char(36) fields in MySQL. Migrating to UUIDv7 as the primary key. UUID v1: is a universally unique identifier that is generated using a timestamp and the MAC address of the computer on which it was generated. The magnitude is, however, difficult to guess. Uuid. That's why numeric PK is the best. When an INSERT occurs, all unique/primary keys must be checked for duplicates. BIGINT Introduction PostgreSQL, a robust open-source relational database management system, is known for its reliability, performance, and replication Aug 20, 2021 · Here is for instance a performance analysis (for MySQL though) comparing using the "official" UUIDs in the wrong way as PK vs. Whether that is relevant or even noticeable in your workload is a completely different question. Sep 23, 2022 · I'm new to databases and have been considering using a UUID as the primary key in my project, but I read some things which made me interested to learn more about the performance. MySQL generates UUID v1 as described in RFC4122. an approach that uses a BIGINT as PK and has the UUID as a separate field. Use auto_increment for primary key, especially before MySQL 8. Jun 10, 2017 · SQL server can cluster on non-primary key columns or not cluster at all (heap organization). Jun 24, 2011 · What's certain is that performance of your database will drop over time. Distributed Systems. An alternative for the Integer Autoincrement Primary Key is the UUID (Universally Unique IDentifier) Primary Key. Jun 29, 2021 · I'm not savvy in the internal workings of MySQL/InnoDB, so my question is: Would it be "better", to have an auto-increment INT(4)/BIGINT(8) Primary Key -- AS WELL AS -- a BINARY(16) Unique Key == or == Just use the non-incremental BINARY(16) as the Primary Key, when facing potentially large dataset? Thanks, JP Aug 11, 2012 · All things InooDB, the PRIMARY KEY has a major role. I have read somewhere that we can use UUID as the primary key of a table. Apr 26, 2025 · Using sqlalchemy. Jul 27, 2009 · @Matt Sheppard I think he means that you can duplicate rows with different GUIDs as primary keys. Apr 19, 2024 · UUID implementation in MySQL. 전역고유성, 벙렬 데이터 생성, 보안성 등을 고려할 때, uuid를 pk로 쓰는 것이 많은 개발자들 상에서 보편화되어있다. The alternative is to use a natural key and those have real problems. A UUID is a 128-bit number. For database like MySQL, Oracle, which uses clustered primary key, both UUIDv1 and UUIDv4 will hurt insertion performance if used as the primary key. Each UUID value typically requires 16 bytes of We all know the Integer Autoincrement Primary Key. Apr 26, 2025 · id UUID PRIMARY KEY: id: Defines a column named "id" to store the UUIDs. MySQL always creates Primary Keys as clustered, and there is no option to switch it off. It is, therefore, an obvious thing to use as a customer number, or in a URL to identify a unique page or row. I don't know whether you consider that to be "strong"; it seems fine. In its simplest form, the relational data model is a collection of tables containing rows of data. Indexing UUIDs Impact on Query Performance. So having UUID as PRIMARY KEY makes the index bigger which cannot be fit into the memory Apr 18, 2017 · create table `guid` ( `id` char(32) not null, primary key (`id`)) The code is the same as the referenced blog post, insert 100K rows in one transaction several times. When you insert a new row without specifying a value for the auto Dec 3, 2022 · Short answer: Yes. Note that this only addresses INSERT speed as this is typically one of the biggest Mar 6, 2022 · For databases like MySQL, Oracle, which use clustered primary key, version 4 randomly generated UUID will hurt insertion performance if used as the primary key. By following best practices in UUID selection, indexing, and performance monitoring, developers can leverage the benefits of UUIDs while ensuring efficient database operations. Jun 14, 2024 · When designing a database, the choice of primary key is a critical decision that can significantly impact performance. TableA - ID int (PK) - Data varchar(100) TableAMap - ID int (PK) - UniversalID GUID (Indexed - nonclustered) Jul 26, 2021 · 今回は MySQL のプライマリキーに UUID を採用する場合に起きるパフォーマンスの問題を仕組みから解説します。MySQL(InnoDB) & UUID のパフォーマンスについては各所でさんざん議論・検証されていますが、論理的に解説した記事が少なかったり一部には誤解を招くようなものもあるため、しっかりと Sep 22, 2015 · Update: MySQL 8. Sep 26, 2023 · This compatibility characteristic allows us to use an existing Postgres UUID column and easily transition the column from storing UUIDv4 values to UUIDv7. (Regular UUIDs are bad for performance because the "next" UUID is nowhere near the "last" UUID. Feb 13, 2023 · We want to test the performance of a sequence/bigint vs UUID(VERSION-4) VS UUID(version-7) on mysql database for primary key/index. 0+). MySQL does not have a built in UUID type. Primary Key must be Unique, cause my database is replicated over machine's that's why I am choosing UUID. When a collision is found, the row is updated incrementing collisions column: INSERT INTO test (uuid) VALUES (uuid_v4()) ON DUPLICATE KEY UPDATE collisions=collisions+1; This blog is mostly eliminated in MySQL 8. A further point to consider is that indexing big UUID columns can slow down the performance of queries. They're a good alternative to sequential ID values for identifiers necessary to link disparate sources of information together. Sep 16, 2024 · MySQLでUUIDをPrimary Keyとして使用する際の問題と解決方法 1. It can be represented by a string, for example: Apr 6, 2025 · In MySQL, using a UUID (Universally Unique Identifier) as a primary key can be a powerful approach for ensuring uniqueness across distributed systems. Due to the fact that it is better to use a numeric column (int) as your primary key in a database, I would like to convert this to an integer but not sure of the best way to handle it. To get the best performance, ensure that any monotonically increasing field is located after the first column of the primary key. This gives you much better insert performance than random UUID (due to Dec 28, 2020 · Usar UUID como tipo numa PK (Primary Key) em vez de Int/BigInt em bancos de dados relacionais (RDBMS) parece ter se tornado comum em aplicações nesse mundo de APIs REST, microsserviços e sistemas distribuídos, afinal temos algumas boas vantagens nessa abordagem: Sep 20, 2023 · Problem. Dec 10, 2024 · In conclusion, generating UUIDs in MySQL and using them as primary keys require careful consideration of performance implications and optimization strategies. For quite some time, I’ve been pondering the question of the PRIMARY KEY in a table. If you plan to store UUID values in a Primary Key column, then you are better off using a TSID (time-sorted unique identifier). UUID V6 & 7 aims to take the best of both worlds without their drawbacks. To demonstrate this create a table named OrderDetails. i. The clock time of queries also indicates a similar performance. Apr 13, 2012 · Updated Answer for MySQL 8. They will generate their own UUID, then insert it later (offline insert). If you are using that as a PRIMARY KEY in InnoDB and you have secondary keys, remember that each secondary key has an implicit copy of the PK, thereby making it bulky. In other words, when a table has a clustered index, the data is Mar 18, 2025 · CREATE TABLE users (id BINARY(16) PRIMARY KEY, name VARCHAR(255)); Use Auto-Incrementing Primary Keys + UUID. Aug 5, 2024 · Though v1 UUID format contains timestamp, it encodes the timestamp using little-endian in that the least significant time appears first, which renders the UUID hard to sort according to creation time. uniqueness must be checked fast; used in other table as foreign key; used to join; The smaller the PK, the better. In the latter case secondary indexes on the table use row IDs (RIDs) to refer to rows from the index. Dec 10, 2024 · The choice between MySQL UUIDs and autoincrement keys for primary key selection involves a trade-off between global uniqueness and performance efficiency. Not reusable. Currently, I am using the uuid data type and the default value is set to gen_random_uuid(). In this case, the nature of values for the Primary Key was very random, which is really bad for a b-tree based storage like InnoDB. That is the entire row is stored on disk based on that key. But it also has limitations. This is an issue with any kind of surrogate key, not just GUIDs. In the database, you would still use a UUID primary key if you prefer, but also store both the hash and the extension in separate columns. This sometimes plays into performance issues. Now one other thought regarding UUID: when doing mass inserts there is a notable difference between "random" order of primary keys and "ordered" primary key values. Aug 4, 2020 · Let's itemize the purposes/goals of a PRIMARY KEY: Uniquely identify each row of a table. If you do larger inserts (or many inserts by parallel user soft your application) making sure to use some form of id which always increases is beneficial as it simplifies Jul 16, 2024 · The server generates a separate primary key, maintains a hash index for fast UUID-to-primary key lookups, and validates the UUID-primary key pair on subsequent requests. 000. This table contains more than 11 millions rows. UUID can come in handy when working with distributed systems that share databases. This makes sense -- you will know which order records were inserted in at a glance, so you can more easily delete them if test data, etc. As UUIDv4 is based solely on randomness, it is extremely portable and can be used with very little prior knowledge about the state of the system. CREATE TABLE users (id BIGINT AUTO_INCREMENT PRIMARY KEY, uuid CHAR(36) UNIQUE, name VARCHAR(255)); Use Partitioned Tables I am coming from MySQL, and in MySQL you can use AUTOINCREMENT for a row's unique id as the primary key. As discussed in the Postgres 8. CHAR keys are indeed slower for joins compared to integer keys 2. Inserting Rows Oct 2, 2020 · Table's primary key will be a foreign key of another table. May 21, 2024 · RDBのPrimary Key(主キー)とは？ MySQL、PostgresQLなどのRDBでは各レコードを識別するために一意な値を必要とします。 これをPrimary Key(主キー)と呼びます。 May 3, 2015 · The data is 'clustered' with the PRIMARY KEY. Oct 3, 2023 · 参照 mysqlでプライマリキーをuuidにする前に知っておいて欲しいこと B+ツリーのリーフノードにおいてプライマリキーの値はソートされて格納されるため、プライマリキーの値がUUIDv4などの時系列順でないランダム値である場合、挿入のたびにB+ツリーの Experiment Run #2 This time around I decided to watch vmstat while the experiment was running. If your UUID is a secondary key, then that BTree suffers from splits/fragmentation. Nov 28, 2016 · Does MySQL support strong GUID so that we could have unique uuid even across databases? You can obviously create your own GUID/UUID and use it as a globally-unique key for whatever you want. As I said before with more than 6 millions rows, there is no difference in performance, it is practically the same. If you know UUID formats, you surely know that the timestamp bits are “shuffled”, so UUIDs don’t follow a chronological order. Dec 9, 2023 · Using a UUID (Universally Unique Identifier) as a primary key in SQL databases has both advantages and disadvantages. We do not have any performance issue at all (and rows in this table are referenced by a lot of different models, and are used pretty much everywhere). e. This tutorial introduces you to MySQL UUID, shows you how to use it as the primary key for a table, and discusses the pros and cons of using it as the PK. This efficiency translates to faster search and retrieval times, especially in large datasets. 또한, 비즈니스적 요구로 uuid가 사용될 수도 있습니다. Nov 29, 2013 · You can also create foreign keys against unique key constraints, which then gives you the option to foreign key to the ID identity as an alternative to the Guid. UUID has 36 characters which make it bulky. Dec 18, 2019 · Technically there would still be some performance impact through the use of an auto-increment column even though you supply your own values. UUID as Primary Key; TSID – Time-Sorted Unique Identifiers. Creating a Table with UUID as Primary Key Some years later, the primary key on that table reached 2 31, and the website was down. May 20, 2009 · When the app goes online, I need to synchronize its database with the central db, and to avoid conflicts and to be able to use a synchronization tool I found, the simplest way is to use a UUID as primary key in each table. There Aug 14, 2020 · The primary key is very important from point of view of relational model. If you want to take it to the most basic of levels, a CHAR is a binary field expecting a 0 to 255 value with the intention of representing said value with a value mapped from a lookup table (in most cases now, UTF8). What negative impacts this decision And it's important to note that you must not use a single surrogate (generated) key as the primary key for a many-to-many relationship table. 2. Now, you have a predictable directory structure based upon the SHA-256 hash of each file and you can write a simple service that can easily store and retrieve any file based upon its hash and extension. Feb 15, 2021 · As we don't control the uuid generation process does (started, app_id_one ) make sense as a primary key for the above structure, are there similar performance issues using uuid version 4 as the second column in a composite key? Oct 6, 2015 · I've created the following test scenario: Insert random UUID v4 as primary key for a table until 40. This is because it requires reordering the rows in order to place the newly inserted row at the right position inside the clustered index. But I am worried about performance. If your concern is that it's easy to "hack", you can add an additional UUID as a natural key. It may also interfere with replication. This example assumes your database engine has native support for UUIDs. 3 documentation there are no methodologies that are universally appropriate to generate these identifiers, but postgreSQL does ship with a few more useful candidates. InnoDB stores data in the PRIMARY KEY order and all the secondary keys also contain PRIMARY KEY. No one can tell you "yes, you'll have 30% less performance if you use UUID()", you'll simply have to measure it yourself if you decide to keep UUID() as primary key. Inserting UUID into Table. Instead there's UUID() which can generate a UUIDv1 as a string of hex numbers. This is enforced by the UNIQUE constraint automatically added by RDBMS on every PK. You can then alter the table and add the necessary primary key constraint. Long answer: The PRIMARY KEY can be almost any datatype with whatever values you can create. The UUID can be used to avoid the AUTO_INCREMENT problems described above. This may not be much of a problem with SQL Server, but it's something to watch out for. Using UUID as a primary key does not inexorably entail performance problems though it might if you made bad choices about indexing. Jan 16, 2024 · Here’s how you might create a migration for a table with a UUID primary key in Laravel. Regular monitoring and adjustments Feb 24, 2025 · CREATE TABLE my_table ( id BINARY(16) NOT NULL PRIMARY KEY, name VARCHAR(255) NOT NULL ); 6: Indexing UUID Columns: Create an index on the UUID column to improve query performance: CREATE INDEX idx_uuid ON my_table (id); 7: Handling Challenges: Be aware of potential performance issues due to the size of UUIDs. A char(32) or char(36) (if including hyphens) is the best data type to store a GUID in lieu of an actual GUID data type. Feb 13, 2023 · The cost of SELECT in case of a numeric primary key if better compared to UUID and VARCHAR primary keys. To understand this, we first need to examine the B+Tree index architecture in MySQL! Dec 9, 2016 · UUIDs can have different underlying structure depending on the version. Here’s how you can use UUID as a primary key in MySQL. Note: The performance was tested on small tables when the query was 100% covered by the index. 1. Create Table SomeTable ( UUID UNIQUEIDENTIFIER NOT NULL, ID INT IDENTITY(1,1) NOT NULL, CONSTRAINT PK PRIMARY KEY NONCLUSTERED (UUID), CONSTRAINT UQ UNIQUE (ID) ) GO Create Table AnotherTable ( SomeTableID INT, FOREIGN KEY Oct 19, 2010 · I doubt you're going to notice much of a performance issue in choice of primary key. Universally Unique Identifiers (UUIDs) are a popular choice for primary keys Dec 22, 2024 · Percona: UUIDs are Popular, but Bad for Performance; UUID or GUID as Primary Keys? Be Careful! Identity Crisis: Sequence v. It provides the disk layout order for the data. Dec 28, 2021 · How to Choose Good IDs. Feb 2, 2009 · As for access time, note that some DBs can start to have BIG problems with GUIDs. Table will have a heavy data (another column may be Text). In this comprehensive guide, we‘ll cover everything you need to know about effectively using UUID in MySQL databases. Being new to mysql and struggling to find an easy way to create data volume easily and test the performance and also 'explain analyze' seems not working here too. PS: space is also a concern so I guess Varchar(36) might be the bad idea Also, rather than using serial, varbinary(16) primary allows for one (we do this) to use uuid_short() for the primary key (not uuid – which is very slow to use as a primary, because it's a string) - which has the feature of ensuring that every record has a key which is unique across the entire database (indeed - network). Such tables' primary keys must only include foreign key references to the tables they are joining, and must necessarily be a compound primary key. As you already know, for MySQL's storage engine (InnoDB) the primary key is very important ! (for performance, memory and disk space). UUID Version 6 and 7 are intended to be used as a primary key in a database. The engine must still update the auto-increment sequence variable in the background so that a value could be generated in the event that no value is supplied in an insert query. You're using more data to store something. It is far more efficient even if you do need a UUID to use an AUTO INC primary key and a secondary UNIQUE on the UUID than it is to use the UUID as the primary key. Many systems will insert to the table, some may specify a UUID when inserting, but some will not. That way, a primary key value can uniquely identify each row. It depends on your generation function and size of the final tables. The globally unique nature of UUID values brings useful properties for certain applications, but also impacts performance and database design considerations. A good practice is to leave the auto-incremental key as the primary key, but add the UUID as an additional identifying field. Mar 28, 2017 · @StephenR UUID is a trusted, well defined standard that should produce collision-free identifiers even when used in large-scale environments. Use MySQL 8's UUID conversion function with the second arg set to true when using UUID as a primary key. UniversalID is used for between systems only. . The TableA. This means that in the Orders database, I have CustomerUuid column. Primary keys should never be exposed, even UUIDs. Having a randomly assigned primary key means that both the primary key and foreign key indexes referencing it have index leaf pages containing a uniform mix of rows of all ages. Use: a Key Mapping Table. TEXT or BLOB are not allowed. Works great, much software is doing it this way. So the UUID will look like '00a0e535-452d-11de-b01e-993b5c1a70e4', which will be stored in a char(36). Aug 13, 2024 · Debugging and troubleshooting performance issues in MySQL databases can be challenging, especially when UUIDs are used as primary keys and visibility into underlying database behavior is limited. It is very important to have as small footprint for PRIMARY KEY as possible: the depth of the index is the minimum payment you have to pay so as to get to a Jan 26, 2020 · The table will have a a lot of inserts/deletes so I've stuck to using a auto increment id for the primary key as opposed to using a uuid as a primary key due to it's associated performance issues. A primary key is, by definition unique within its scope. Jan 27, 2025 · However, because UUIDs are larger than typical integers, they may have some performance overhead. ID is used locally in your database as the Primary Key, and the key to use for JOINing. Feb 24, 2025 · CREATE TABLE my_table ( id BINARY(16) NOT NULL PRIMARY KEY, name VARCHAR(255) NOT NULL ); 6: Indexing UUID Columns: Create an index on the UUID column to improve query performance: CREATE INDEX idx_uuid ON my_table (id); 7: Handling Challenges: Be aware of potential performance issues due to the size of UUIDs. UUID can be generated client side, or server side. I know this is the case with MySQL (MySQL InnoDB Primary Key Choice: GUID/UUID vs Integer Insert Performance). GUIDs are intended to be globally unique identifiers. MySQL has its builtin UUID() function, which is "Type-1". Hi, I have read that mariadb/mysql has a performance impact with UUID as primary key, but if I use ULID which are sequential and sortable and saved as binary, would it also have a performance impact compared to intenger autoincrementing? Jan 30, 2020 · Another issue is if your UUID primary key is clustered (such as with MySQL's InnoDB) there is a cost to row re-ordering when inserting random UUIDs. By Sep 25, 2023 · The UUID should not be the only key that identifies an entity. Good IDs are: Unique (no collisions). 0. To use UUIDs in MySQL as a primary key, we must first understand how to generate them. The main purpose of having UUID as the primary key is the ability to share the data across distributed systems. Having both a UNIQUE AUTO_INCREMENT and a UNIQUE UUID in the same table is a waste. Use Case. a. As noted by Kazimieras Aliulis in the comments, support for descending indexes is being added in MySQL 8. If you read articles about "indexing" that were talking about MySQL or SQL Server rather than being Postgres specific, then they are pretty much moot, due to the completely different way primary keys (and foreign keys) are stored in Postgres. I've personally seen massive performance gains when breaking up the previous GUID-based Primary / Clustered Key into two separate key - the primary (logical) key on the GUID, and the clustering (ordering) key on a separate INT IDENTITY(1,1) column. What I always do, even if it's redundant is I create primary key on auto increment column (I call it technical key) to keep it consistent within the database, allow for "primary key" to change in case something went wrong at design phase and also allow for less space to be consumed in case Dec 27, 2023 · Universally Unique Identifiers (UUID) are an interesting data type in MySQL. Uuid will use the native UUID type if supported by the database (like PostgreSQL) and fall back to storing it as a 32-character string in databases that don't have a native UUID type (like SQLite). Works well with clusters see 1 and 3 UUID is 16 bytes (when properly stored as a UUID type -- or 37 bytes when stored as a string -- don't do this!) while a BIGINT is 8 bytes (or even an INT only 4 bytes if you only need max 2 billion different values) so BIGINT is faster. UUID: Specifies that the "id" column will store UUID values. Apr 23, 2022 · Most databases use incrementing id's because it's more efficient to insert a new value onto the end of a B-tree based index. It is tempting to declare the UUID VARCHAR(36) . Dec 21, 2019 · I wanted to ask whether databases automatically create an index for the the chosen primary_key If the UUID primary_key index is the problem, would the insert problem be solved by using an integer as the primary_key index while still keeping the UUID field, then switching the primary keys to UUID, the problem then is would the foreign key Mar 12, 2013 · For database like MySQL, Oracle, which uses clustered primary key, version 4 randomly generated UUID will hurt insertion performance if used as the primary key. May 3, 2016 · Is it possible to generate a UUID version 4 (completely random) in MySQL? I would like to use it as a primary key. The baseline implementation uses the GUID Id column for both the Primary Key and Clustered Index. The randomness of UUID V4 has a negative impact on performance when used as a key in a database and UUID V1 exposed the MAC address of the machine where it was created. Indexing is a critical aspect of database performance, and this holds true for UUID in MySQL Sep 9, 2022 · More and more people are using UUID's to identify records in their database. The data conflagrations I've seen arising from using a There is a performance difference, yes. If your database is small then it is ok, otherwise, you can consider converting it to binary using mysql's built-in functions (mysql 8. This is because it requires reordering the rows to place the newly inserted row at the right position inside the clustered index. Creating a Table with UUID as Primary Key. So, if I want to query a customer's orders, I should use where CustomerUuid = 'uuid_valu'. Reusing a deleted row PK is technically possible in relational databases but is a very bad idea because it contributes to generating confusion (for example, an older log file can reference an ID reused in the meantime by a new entity Oct 29, 2010 · MySQL does not provide a GUID/UUID type, so you would need to generate the key in the code you're using to insert rows into the DB. UUIDをPKとして使用した場合の問題. Oct 16, 2014 · Alternatively, I think you can create the table without declaring the PK at first, in which case MySQL will create an automatic clustered index based on row IDs. It occupies less storage. By default, I recommend just using an auto-increment primary key. sqlalchemy. js function to do similar thing May 26, 2015 · For MySQL, which uses clustered primary key, version 4 randomly generated UUID will hurt insertion performance if used as the primary key. Access patterns in databases tend to follow approximately a power law, recent rows are much more probable to be accessed. 5 days ago · 前提として、通常はuuidとauto_incrementを同時にprimary keyとして使うことはありません。primary keyは1つだけです。ここで言う「併用」とは、テーブル内にuuidカラムとauto_incrementカラムの両方を持つことを指し、どちらかをprimary keyに、もう一方をunique keyにすることが一般的です。 May 20, 2009 · In InnoDB, If the primary key is long, the secondary indexes use more space, so it is advantageous to have a short primary key. Graphical display of the random nature of UUID on PRIMARY KEY Benchmarks, etc, by Karthik Appigatla More details on the clock A StackExchange discussion NEXTSEQUENTIALID() would be nice Good analysis of UUID performance NHibernate can generate sequential GUIDs but it seems to be backwards. Node. tbqw gqtmveyj bhv gpq jodf nkus lcjv xzmtl dgmcg ucadgt