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New Features in HyperSQL 2.2

This document lists the enhancements and new features since version 1.8.0. An extensive range of new SQL and JDBC capabilities, increased scalability, and better query optimisation have been achieved by a rewrite of most of the internal components and the addition of some major new ones.

All areas of functionality have been thoroughly tested with an extensive internal test suite and by users with their applications. HyperSQL 2.0 went into alpha release in April 2009 and 9 alpha, beta and RC releases were made before the final release in June 2010. All code was reviewed twice during the RC phase and many bugs were found and fixed. Each RC version was downloaded up to 20000 times and over 200 users submitted bug reports which were promptly fixed. During the first half of 2010, several users successfully deployed the RC versions in heavily loaded production environments.

An extensive Guide was written over two years to cover all features of the engine in detail.

Since the first release, many enhancements were introduced. More code reviews, user feedback, and bug fixes resulted in the latest 2.2.x point releases.

NEW CORE

Fully multithreaded core supports 2PL (two-phased locking) and MVCC (multiversion concurrency control), plus a hybrid 2PL+MVCC transaction control mode. Transactions can be SERIALIZABLE or READ COMMITTED, using strict 2PL concurrency control. Version 2.0 also adds the MVCC modes, SNAPSHOT ISOLATION and READ CONSISTENCY, which are comparable to REPEATABLE READS and READ COMMITTED isolation levels, but with higher concurrency. Many enhancements are introduced to allow maximum multi-threaded concurrency in different isolation modes.

SCALABILITY

Massive high performance LOB store for BLOBs and CLOBs up to multi-gigabyte size, with total storage capacity of 64 terabytes.

Increased default storage space of 16GB for ordinary data, with fast startup and shutdown. Storage space can be extended to 2TB.

Large result sets, views and subqueries can now be stored on disk (on the server side) while being generated and accessed. The threshold to store a result on disk, as well as the actual fetch size in client-server configurations can be specified per connection.

Internal and external commands for backing up databases to TAR and GZIP archives.

QUERY OPTIMISATION

All query conditions, whether in a JOIN or WHERE clause, are now allocated to an index if possible. IN queries are now optimised to use an index if possible. Conditions with OR are optimised if indexes can be used. MAX(), MIN() and ORDER BY with or without LIMIT and OFFSET expressions can use indexes. All indexes can be used in reverse order for these operations. Indexes on multiple columns are used efficiently.

SQL STORED PROCEDURES AND FUNCTIONS

HyperSQL supports schema-based stored procedures and functions written entirely in SQL. Procedural SQL language includes WHILE loops, IF, CASE WHEN, and exception handling statements. Recursive functions are supported. SQL procedures can return multiple result sets and return values. SQL functions can return single values, arrays, or tables that can be used in SQL queries. User defined aggregate functions written in SQL are supported.

JAVA STORED PROCEDURES AND FUNCTIONS

HyperSQL supports schema-based stored procedures and functions written entirely in JAVA. Polymorphism is supported. User defined aggregate functions are supported. Java procedures can return multiple result sets and return values. Java functions can can return single values, arrays or even tables that can be used in SQL queries. 

NEW DATA TYPES

Support for BIT, BIT VARYING, CLOB, BLOB, INTERVAL according to the SQL Standards. TIME can now have a fractional second part. TIME WITH TIME ZONE and TIMESTAMP WITH TIME ZONE are supported. The full range of combinations of datetime and interval types is supported. Support for DOMAIN objects with constraints and DISTINCT types.

ARRAY TYPES

Arrays of most types can be used in table definitions, expressions, function parameters and return types.

COLLATIONS

Multiple collations can be used for different tables or columns. A collation can be specified for ORDER BY.

NEW EXPRESSION TYPES

Complete rewrite of scanner and parser classes. Supports all SQL standard identifier and character string literals (Unicode strings and escapes, etc.).

Supports extended CASE WHEN conditions such as CASE X WHEN IN (,,), BETWEEN A AND B, 21, 56, IS NULL THEN ..

UNIQUE(SELECT ..) predicate.

(A,B) OVERLAPS(X,Y) predicated.

Supports Z BETWEEN [SYMMETRIC | ASYMMETRIC] (X, Y) predicate.

Multi-column (A,B,C) IN ((,,), (,,), ) both with literals and queries

Supports (A, B, C) {= | > | < | <> |}(W,X,Y,Z) predicates.

Supports (A,B,C) IS [NOT] DISTINCT FROM (W,X,Y,Z) predicates

Supports (A,B,C) MATCHES [UNIQUE] [SIMPLE]|[PARTIAL]|[FULL] (SELECT ) predicates.

Supports (A,B,C) {= | < | > | <= | >=} {ANY | ALL} SELECT predicates.

Full Standard syntax and semantics (arithmetic and other operations) of expressions involving INTERVAL types. Supports type casts to INTERVAL types modifiers (e.g. <expression> DAY). Supports WITH TIME ZONE data types, including zone modifiers (i.e. <expression> AT LOCAL | AT TIME ZONE ).

Supports standard SQL grammar, including IS [NOT] {NULL | TRUE | FALSE | UNKNOWN}.

Supports expressions in all LIKE arguments.

NEW DATA MANIPULATION LANGUAGE FEATURES

Both INSERT and UPDATE command have been enhanced to support multi-row inserts, omission of parentheses, DEFAULT keyword, mix of subquery and row expressions. The powerful MERGE command is fully supported.

INSERT INTO VALUES (expr,expr, ..), (expr,expr, ),

INSERT INTO VALUES expr

INSERT INTO .. DEFAULT VALUES

INSERT INTO VALUES (expr, DEFAULT, ..)

UPDATE SET A = DEFAULT, ..

UPDATE SET (A, B, ..) = (expr, DEFAULT,), C = expr, (D,E) = (SELECT )

MERGE statement with full Standard compliant syntax is supported

TRUNCATE TABLE is fully supported

NEW DATA QUERY LANGUAGE FEATURES

SELECT

SELECT has been extensively enhanced, supporting all Standard join types.

The scope of column labels in SELECT queries is now treated according to the SQL Standard. Labels are visible in the ORDER BY expression but not in GROUP BY

Supports TABLE X to introduce the equivalent of SELECT * FROM TABLE X in set operations.

Supports VALUES (,,,), (,,,) as table constructor in joins.

Supports TABLE, LATERAL and UNNEST table constructor in joins.

Supports WITH RECURSIVE for named subqueries allow recursive queries.

Supports column name list after correlation name SELECT .. FROM A AS B (X,Y,Z) JOIN C

[LEFT | RIGHT | FULL {OUTER}] JOIN

UNION JOIN

[LEFT | RIGHT | FULL {OUTER}] NATURAL JOIN

[LEFT | RIGHT | FULL {OUTER}] JOIN USING (A, B, ..)

SELECT * with the above joins now returns the correct column sequence as per SQL Standard

JOIN conditions can now contain any valid boolean expressions.

Support for UNION {ALL|DISTINCT}, INTERSECT {ALL|DISTINCT} and EXCEPT {ALL|DISTINCT}

Support for all the above with CORRESPONDING[(<column list>)}

Support for <joined table>, e.g. SELECT FROM (table1 OUTER JOIN table2) JOIN table3

Support for NULLS FIRST, NULLS LAST in ORDER BY

Full support for inclusion of set functions (e.g. COUNT, AVG) in subquery conditions contained within a HAVING clause. Includes support for user-defined aggregate functions

Supports FETCH <row count> ROWS ONLY as SQL Standard alternative to LIMIT at the end of query expression

DATA DEFINITION LANGUAGE ENHANCEMENTS

Supports full syntax of SQL TRIGGER definition for row level triggers using SQL procedure statements (as well as Java classes)

CREATE TRIGGER <name> {BEFORE | AFTER}
{INSERT | DELETE | UPDATE [OF (<column name>, ..)]
ON <table name>
[ REFERENCING OLD [ROW] [AS] <old transition variable name> |
NEW [ROW] [AS] <new transition variable name>]
[FOR EACH ROW]
[WHEN (<search condition>)]
<sql procedure statement block>

Supports full set of SEQUENCE generator options ([NO] MAXVALUE, [NO] MINVALUE, [NO] CYCLE, etc.) and data types including SMALLINT, INT, BIGINT, DECIMAL, NUMERIC. These are supported in IDENTITY sequences and in normal sequences, including all relevant ALTER COLUMN and ALTER SEQUENCE commands.

Supports GENERATED {BY DEFAULT | ALWAYS} AS IDENTITY in a different column than the PRIMARY KEY column.

A user supplied value or a value returned from a SELECT statement can always be inserted into an identity column. If GENERATED ALWAYS has been specified, then OVERRIDING SYSTEM VALUE must be included in the INSERT statement.

Supports GENERATED ALWAYS AS <expression> for derivative columns that are based on other column values.

Extended CREATE SCHEMA . statements can include cross references between FOREIGN KEY constraints in different tables.

Supports CREATE TABLE .. (<column list>) AS (<query expression>) WITH [NO] DATA

CREATE TABLE can have mixed column and constraint creation elements. A column definition can include a PRIMARY KEY, UNIQUE, FOREIGN KEY or CHECK constraint,

Similarly, ALTER TABLE ADD COLUMN can feature constraint definitions.

ALTER TABLE ALTER COLUMN SET DATA TYPE supported.

Supports CASCADE with ALTER TABLE .. DROP COLUMN and ALTER TABLE DROP CONSTRAINT.

Named NOT NULL constraints now supported in column definition CONSTRAINT C NOT NULL. All NOT NULL constraints are treated as CHECK (C IS NOT NULL) type constraints and listed as such in system tables.

Supports VIEW definitions including tables and sequences in other schemas.

Supports updatable views, including WITH {LOCAL | CASCADED} CHECK OPTION

SQL FUNCTIONS

A wide set of SQL Standard functions, including correct type handling and application to all supported types (e.g. BINARY, BLOB, CLOB), is now supported.

SUBSTRING for character (CHAR, VARCHAR, CLOB) and binary (BINARY, VARBINARY, BLOB) types.
UPPER, LOWER for all character types
TRIM for all character types
OVERLAY for all character types
POSITION
CHAR_LENGTH, CHARACTER_LENGTH, OCTET_LENGTH
EXTRACT
ABS for all number types

An extended set of extra functions is also supported, including:

TO_CHAR, TO_DATE, TRUNCATE
REGXP_MATCHES, REGXP_SUBSTRING, REGX_SUBSTRING_ARRAY
DECODE, GREATEST, etc.

OTHER SQL FEATURES

Supports column level SELECT, INSERT and UPDATE access rights, with GRANT and REVOKE on individual columns of tables, including WITH GRANT OPTION. GRANT SELECT(A, D) ON X TO U

Supports SQL STATE with messages defined by the standard

COMPATIBILITY FEATURES

Supports several syntax and operation compatibility flags to ease testing and porting applications written against a different database engine. These include PostgreSQL, MySQL, Oracle, MS SQL Server and DB2

JDBC FEATURES

Supports getGeneratedKeys() calls in Statement and PreparedStatement.

Supports CallableStatement with multiple result sets and IN and OUT parameters

Supports POSIX functions TIMESTAMPDIFF and TIMESTAMPADD.

Supports Java 1.6 and JDBC4. All applicable new methods are supported.

INFORMATION SCHEMA

Supports SQL Standard INFORMATION SCHEMA views, together with additional views used in JDBC. Altogther some 90 view are supported. Standard views are supported correctly and reflect the user's permissions on database objects.

OTHER FEATURES

The Server now supports remote opening of databases. 

Supports advanced external user authentication and password complexity checks.

Supports SQL statement logging as well as external framework logging via Log4J and JRE logging.

SQL STANDARD FEATURE LIST

SQL-92 direct SQL is supported fully to Advanced Level except for deferrable constraint enforcement, ASSERTION, and CHECK constraints that contain subqueries.

All SQL:2003 - SQL:2008 Standard CORE features are supported.

HSQLDB 2.2.X also supports the following set of SQL:1999, SQL:2003 and SQL:2008 NON-CORE features. (some features not yet added to this list)

B031 Direct SQL
C071-01 Read-only scrollable cursors (via JDBC ResultSet)
F032 CASCADE drop behaviour
F033 ALTER TABLE statement: DROP COLUMN clause
F034 Extended REVOKE statement
F034-1 REVOKE statement performed by other than the owner of a schema object
F034-2 REVOKE statement: GRANT OPTION FOR clause
F034-3 REVOKE statement to revoke a privilege that the grantee has WITH GRANT OPTION
F052 Interval and datetime arithmetic
F053 OVERLAPS predicate
F171 Multiple schemas per user
F191 Referential delete actions
F200 TRUNCATE TABLE statement
F202 TRUNCATE TABLE: identity column restart option
F222 INSERT statement: DEFAULT VALUES clause
F231 Privilege tables
F231-01 TABLE_PRIVILEGES view
F231-02 COLUMN PRIVILEGES view
F231-03 USAGE PRIVILEGES view
F251 Domain Support
F262 Extended CASE expression
F263 Comma-separated predicates in simple CASE expression
F271 Compound character literals
F291 UNIQUE predicate
F301 CORRESPONDING in query expressions
F302 INTERSECT table operator
F302-1 INTERSECT DISTINCT table operator
F302-2 INTERSECT ALL table operator
F304 EXCEPT ALL
F312 MERGE statement
F321 User authorization
F381 Extended schema manipulation
F381-01 ALTER TABLE statement: ALTER COLUMN clause
F381-02 ALTER TABLE statement: ADD CONSTRAINT clause
F381-03 ALTER TABLE statement: DROP CONSTRAINT clause
F382 Alter column data type
F391 Long identifiers
F392 Unicode escapes in identifiers
F393 Unicode escape in literals
F401 Extended joined table
F401-01 NATURAL JOIN
F401-02 FULL OUTER JOIN
F401-04 CROSS JOIN
F402 Named column joins for LOBs, arrays, and multisets
F411 Time zone specification
F421 National character
F431 Read-only scrollable cursor
F441 Extended set function support
F442 Mixed column references in set functions
F451 Character set definition
F461 Named character sets
F491 Constraint management
F502 Enhanced documentation tables
F502-01 SQL_SIZING_PROFILES view
F502-02 SQL_IMPLEMENTATION_INFO view
F502-03 SQL_PACKAGES view
F511 BIT data type
F531 Temporary tables
F555 Enhanced seconds precision
F561 Full value expressions
F571 Truth value tests
F591 Derived table
F641 Row and table constructors
F651 Catalog name qualifiers
F661 Simple Tables
F672 Retrospective check constraints
F690 Collation support (limited)
F701 Referential update actions
F711 ALTER domain
F731 INSERT column privileges
F751 View CHECK enhancements
F762 CURRENT_CATALOG
F763 CURRENT_SCHEMA
F781 Self-referencing operations
F791 Insensitive cursors
F801 Full set function
F831 Full cursor update
F850 Top-level <order by clause> in <query expression>
F851 <order by clause> in subqueries
F852 Top-level <order by clause> in views
F855 Nested <order by clause> in <query expression>
F856 Nested <fetch first clause> in <query expression>
F857 Top-level <fetch first clause> in <query expression>
F858 <fetch first clause> in subqueries
F859 Top-level <fetch first clause> in views
F860 <fetch first row count> in <fetch first clause>
F861 Top-level <result offset clause> in <query expression>
F862 <result offset clause> in subqueries
F863 Nested <result offset clause> in <query expression>
F864 Top-level <result offset clause> in views
F821 Local table references
F865 <offset row count> in <result offset clause>
S091 Basic array support
S091-01 Arrays of built-in data types
S091-02 Arrays of distinct types
S091-03 Array expressions
S095 Array constructors by query
S096 Optional array bounds
S097 Array element assignment
S201 SQL-invoked routines on arrays
S201-01 Array parameters
S201-02 Array as result type of functions
S301 Enhanced UNNEST
T011 Timestamp in Information Schema
T021 BINARY and VARBINARY data types
T022 Advanced BINARY and VARBINARY data type support
T023 Compound binary literals
T024 Spaces in binary literals
T031 BOOLEAN data type
T041 Basic LOB data type support
T041-01 BLOB data type
T041-02 CLOB data type
T041-03 POSITION, LENGTH etc functions for LOB data types
T021-04 Concatenation of LOB data types
T071 BIGINT data type
T151 DISTINCT predicate
T152 DISTINCT predicate with negation
T172 AS subquery clause in table definition
T174 Identity columns
T176 Sequence generator support
T177 Sequence generator support: simple restart option
T178 Identity columns: simple restart option
T191 Referential action RESTRICT
T201 Comparable data types for referential constraints
T211 Basic trigger capability
T211-01 Triggers activated on UPDATE, INSERT, or DELETE of one base table.
T211-02 BEFORE triggers
T211-03 AFTER triggers
T211-04 FOR EACH ROW triggers
T211-05 Ability to specify a search condition that shall be True before the trigger is invoked.
T211-06 Support for run-time rules for the interaction of triggers and constraints.
T211-07 TRIGGER privilege
T211-08 Multiple triggers for the same event are executed in the order in which they were created in the catalog.
T271 Savepoints
T281 SELECT privilege with column granularity
T285 Enhanced derived column names
T301 Functional dependencies
T312 OVERLAY function
T326 Table functions
T331 Basic roles
T332 Extended roles (partial)
T351 Bracketed SQL comments
T441 ABS and MOD functions
T461 Symmetric BETWEEN predicate
T471 Result sets return value
T491 LATERAL derived table
T501 Enhanced EXISTS predicate
T551 Optional key words for default syntax
T571 Array-returning external SQL-invoked functions
T591 UNIQUE constraints of possibly null columns
T621 Enhanced numeric functions
T641 Multiple column assignment

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This page last updated 27 Feb 2012
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