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Before 8.0, when a user create a descending index, we created an ascending index and scanned it backwards. Values in such an index are arranged in descending order, and we scan it forward. MySQL 8.0 delivers support for indexes in descending order.

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We also want to say thank you to Kyle Oppenheim for his code contribution! See blog post by Martin Hansson here. NOWAIT and SKIP LOCKED are frequently requested SQL features. Instead, the locked rows are skipped and not read at all. A locking clause using SKIP LOCKED will never wait to acquire a row lock on the listed tables. Instead, the query will fail with an error. A locking clause using NOWAIT will never wait to acquire a row lock. In some use cases there is a need to either return immediately if a row is locked or ignore locked rows. FOR UPDATE, any other transaction will have to wait to access that locked row.

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Normally, when a row is locked due to an UPDATE or a SELECT. MySQL 8.0 delivers NOWAIT and SKIP LOCKED alternatives in the SQL locking clause. See blog posts by Guilhem Bichot here, here, here, and here. CTE is a commonly requested SQL feature, see for example feature request 1624. A recursive CTE is a set of rows which is built iteratively: from an initial set of rows, a process derives new rows, which grow the set, and those new rows are fed into the process again, producing more rows, and so on, until the process produces no more rows. Non-recursive CTEs can be explained as “improved derived tables” as it allow the derived table to be referenced more than once. MySQL 8.0 delivers Common Table Expressions (CTEs). See blog post by Dag Wanvik here as well as blog post by Guilhem Bichot here. Window functions have long been part of standard SQL (SQL 2003). analytic functions) is a frequent user request.

The set of specialized window functions are: RANK, DENSE_RANK, PERCENT_RANK, CUME_DIST, NTILE, ROW_NUMBER, FIRST_VALUE, LAST_VALUE, NTH_VALUE, LEAD and LAG This is the set of aggregate functions in MySQL that support windowing: COUNT, SUM, AVG, MIN, MAX, BIT_OR, BIT_AND, BIT_XOR, STDDEV_POP (and its synonyms STD, STDDEV), STDDEV_SAMP, VAR_POP (and its synonym VARIANCE) and VAR_SAMP. Window functions come in two flavors: SQL aggregate functions used as window functions and specialized window functions. But where a grouped aggregate collapses this set of rows into a single row, a window function will perform the aggregation for each row in the result set. Similar to grouped aggregate functions, window functions perform some calculation on a set of rows, e.g. Finally there are improvements in Datatypes, with bit-wise operations on BINARY datatypes and improved IPv6 and UUID functions. Developers also want to be able to store Emojis, thus UTF8MB4 is now the default character set in 8.0. MySQL Developers want new features and MySQL 8.0 delivers many new and much requested features in areas such as SQL, JSON, Regular Expressions, and GIS. Or perhaps you prefer to just look at the source code at /mysql.

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The above represents some of the highlights and I encourage you to further drill into the complete series of Milestone blog posts- 8.0.0, 8.0.1, 8.0.2, 8.0.3, and 8.0.4 -and even further down in to the individual worklogs with their specifications and implementation details. Added Resource Group feature to give users an option optimize for specific workloads on specific hardware by mapping user threads to CPUs. Performance InnoDB is significantly better at Read/Write workloads, IO bound workloads, and high contention “hot spot” workloads.

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Security OpenSSL improvements, new default authentication, SQL Roles, breaking up the super privilege, password strength, and more.

Manageability Remote management, Undo tablespace management, and new instant DDL.

Observability Significant enhancements to Performance Schema, Information Schema, Configuration Variables, and Error Logging.

Reliability DDL statements have become atomic and crash safe, meta-data is stored in a single, transactional data dictionary.

Spatial Reference Systems (SRS), as well as SRS aware spatial datatypes, spatial indexes, and spatial functions.

With JSON table functions you can use the SQL machinery for JSON data.

JSON Extended syntax, new functions, improved sorting, and partial updates.

SQL Window functions, Common Table Expressions, NOWAIT and SKIP LOCKED, Descending Indexes, Grouping, Regular Expressions, Character Sets, Cost Model, and Histograms.

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Download now! MySQL 8.0 is an extremely exciting new version of the world’s most popular open source database with improvements across the board. We proudly announce General Availability of MySQL 8.0.