Package org.h2.engine

Class Constants

java.lang.Object
org.h2.engine.Constants
public class Constants extends Object
Constants are fixed values that are used in the whole database code.

  • Field Details

    • BUILD_DATE

      public static final String BUILD_DATE
      The build date is updated for each public release.
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    • BUILD_ID

      public static final int BUILD_ID
      Sequential version number. Even numbers are used for official releases, odd numbers are used for development builds.
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    • BUILD_SNAPSHOT

      public static final boolean BUILD_SNAPSHOT
      Whether this is a snapshot version.
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    • BUILD_VENDOR_AND_VERSION

      public static final String BUILD_VENDOR_AND_VERSION
      If H2 is compiled to be included in a product, this should be set to a unique vendor id (to distinguish from official releases). Additionally, a version number should be set to distinguish releases. Example: ACME_SVN1651_BUILD3

    • TCP_PROTOCOL_VERSION_17

      public static final int TCP_PROTOCOL_VERSION_17
      The TCP protocol version number 17.
      Since:
      1.4.197 (2018-03-18)
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    • TCP_PROTOCOL_VERSION_18

      public static final int TCP_PROTOCOL_VERSION_18
      The TCP protocol version number 18.
      Since:
      1.4.198 (2019-02-22)
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    • TCP_PROTOCOL_VERSION_19

      public static final int TCP_PROTOCOL_VERSION_19
      The TCP protocol version number 19.
      Since:
      1.4.200 (2019-10-14)
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    • TCP_PROTOCOL_VERSION_20

      public static final int TCP_PROTOCOL_VERSION_20
      The TCP protocol version number 20.
      Since:
      2.0.202 (2021-11-25)
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    • TCP_PROTOCOL_VERSION_21

      public static final int TCP_PROTOCOL_VERSION_21
      The TCP protocol version number 21.
      Since:
      2.3.230 (TODO)
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    • TCP_PROTOCOL_VERSION_MIN_SUPPORTED

      public static final int TCP_PROTOCOL_VERSION_MIN_SUPPORTED
      Minimum supported version of TCP protocol.
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    • TCP_PROTOCOL_VERSION_MAX_SUPPORTED

      public static final int TCP_PROTOCOL_VERSION_MAX_SUPPORTED
      Maximum supported version of TCP protocol.
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    • VERSION_MAJOR

      public static final int VERSION_MAJOR
      The major version of this database.
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    • VERSION_MINOR

      public static final int VERSION_MINOR
      The minor version of this database.
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    • LOCK_MODE_OFF

      public static final int LOCK_MODE_OFF
      The lock mode that means no locking is used at all.
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    • LOCK_MODE_READ_COMMITTED

      public static final int LOCK_MODE_READ_COMMITTED
      The lock mode that means read locks are acquired, but they are released immediately after the statement is executed.
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    • LOCK_MODE_TABLE

      public static final int LOCK_MODE_TABLE
      The lock mode that means table level locking is used for reads and writes.
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    • LOCK_MODE_TABLE_GC

      public static final int LOCK_MODE_TABLE_GC
      The lock mode that means table level locking is used for reads and writes. If a table is locked, System.gc is called to close forgotten connections.
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    • ALLOW_LITERALS_ALL

      public static final int ALLOW_LITERALS_ALL
      Constant meaning both numbers and text is allowed in SQL statements.
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    • ALLOW_LITERALS_NONE

      public static final int ALLOW_LITERALS_NONE
      Constant meaning no literals are allowed in SQL statements.
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    • ALLOW_LITERALS_NUMBERS

      public static final int ALLOW_LITERALS_NUMBERS
      Constant meaning only numbers are allowed in SQL statements (but no texts).
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    • TRANSACTION_SNAPSHOT

      public static final int TRANSACTION_SNAPSHOT
      SNAPSHOT isolation level of transaction.
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    • CACHE_MIN_RECORDS

      public static final int CACHE_MIN_RECORDS
      The minimum number of entries to keep in the cache.
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    • CACHE_TYPE_DEFAULT

      public static final String CACHE_TYPE_DEFAULT
      The default cache type.
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    • CLUSTERING_DISABLED

      public static final String CLUSTERING_DISABLED
      The value of the cluster setting if clustering is disabled.
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    • CLUSTERING_ENABLED

      public static final String CLUSTERING_ENABLED
      The value of the cluster setting if clustering is enabled (the actual value is checked later).
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    • CONN_URL_COLUMNLIST

      public static final String CONN_URL_COLUMNLIST
      The database URL used when calling a function if only the column list should be returned.
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    • CONN_URL_INTERNAL

      public static final String CONN_URL_INTERNAL
      The database URL used when calling a function if the data should be returned.
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    • COST_ROW_OFFSET

      public static final int COST_ROW_OFFSET
      The cost is calculated on rowcount + this offset, to avoid using the wrong or no index if the table contains no rows _currently_ (when preparing the statement)
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    • DEADLOCK_CHECK

      public static final int DEADLOCK_CHECK
      The number of milliseconds after which to check for a deadlock if locking is not successful.
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    • DEFAULT_HTTP_PORT

      public static final int DEFAULT_HTTP_PORT
      The default port number of the HTTP server (for the H2 Console). This value is also in the documentation and in the Server javadoc.
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    • DEFAULT_LOCK_MODE

      public static final int DEFAULT_LOCK_MODE
      The default value for the LOCK_MODE setting.
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    • DEFAULT_MAX_LENGTH_INPLACE_LOB

      public static final int DEFAULT_MAX_LENGTH_INPLACE_LOB
      The default maximum length of an LOB that is stored with the record itself, and not in a separate place.
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    • DEFAULT_MAX_OPERATION_MEMORY

      public static final int DEFAULT_MAX_OPERATION_MEMORY
      The default for the setting MAX_OPERATION_MEMORY.
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    • DEFAULT_PAGE_SIZE

      public static final int DEFAULT_PAGE_SIZE
      The default page size to use for new databases.
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    • DEFAULT_RESULT_SET_CONCURRENCY

      public static final int DEFAULT_RESULT_SET_CONCURRENCY
      The default result set concurrency for statements created with Connection.createStatement() or prepareStatement(String sql).
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    • DEFAULT_TCP_PORT

      public static final int DEFAULT_TCP_PORT
      The default port of the TCP server. This port is also used in the documentation and in the Server javadoc.
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    • DEFAULT_WRITE_DELAY

      public static final int DEFAULT_WRITE_DELAY
      The default delay in milliseconds before the transaction log is written.
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    • ENCRYPTION_KEY_HASH_ITERATIONS

      public static final int ENCRYPTION_KEY_HASH_ITERATIONS
      The password is hashed this many times to slow down dictionary attacks.
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    • FILE_BLOCK_SIZE

      public static final int FILE_BLOCK_SIZE
      The block of a file. It is also the encryption block size.
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    • INITIAL_LOCK_TIMEOUT

      public static final int INITIAL_LOCK_TIMEOUT
      For testing, the lock timeout is smaller than for interactive use cases. This value could be increased to about 5 or 10 seconds.
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    • IO_BUFFER_SIZE

      public static final int IO_BUFFER_SIZE
      The block size for I/O operations.
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    • IO_BUFFER_SIZE_COMPRESS

      public static final int IO_BUFFER_SIZE_COMPRESS
      The block size used to compress data in the LZFOutputStream.
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    • LOCK_SLEEP

      public static final int LOCK_SLEEP
      The number of milliseconds to wait between checking the .lock.db file still exists once a database is locked.
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    • MAX_IDENTIFIER_LENGTH

      public static final int MAX_IDENTIFIER_LENGTH
      The maximum allowed length of identifiers.
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    • MAX_COLUMNS

      public static final int MAX_COLUMNS
      The maximum number of columns in a table, select statement or row value.
      See Also:

    • MAX_STRING_LENGTH

      public static final int MAX_STRING_LENGTH
      The maximum allowed length for character string, binary string, and other data types based on them; excluding LOB data types.

      This needs to be less than (2^31-8)/2 to avoid running into the limit on encoding data fields when storing rows.

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    • MAX_NUMERIC_PRECISION

      public static final int MAX_NUMERIC_PRECISION
      The maximum allowed precision of numeric data types.
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    • MAX_ARRAY_CARDINALITY

      public static final int MAX_ARRAY_CARDINALITY
      The maximum allowed cardinality of array.
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    • MAX_PARAMETER_INDEX

      public static final int MAX_PARAMETER_INDEX
      The highest possible parameter index.
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    • MEMORY_OBJECT

      public static final int MEMORY_OBJECT
      The memory needed by a regular object with at least one field.
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    • MEMORY_ARRAY

      public static final int MEMORY_ARRAY
      The memory needed by an array.
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    • MEMORY_POINTER

      public static final int MEMORY_POINTER
      The memory needed by a pointer.
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    • MEMORY_ROW

      public static final int MEMORY_ROW
      The memory needed by a Row.
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    • PREFIX_INDEX

      public static final String PREFIX_INDEX
      The name prefix used for indexes that are not explicitly named.
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    • PREFIX_JOIN

      public static final String PREFIX_JOIN
      The name prefix used for synthetic nested join tables.
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    • PREFIX_PRIMARY_KEY

      public static final String PREFIX_PRIMARY_KEY
      The name prefix used for primary key constraints that are not explicitly named.
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    • PREFIX_QUERY_ALIAS

      public static final String PREFIX_QUERY_ALIAS
      The name prefix used for query aliases that are not explicitly named.
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    • PUBLIC_ROLE_NAME

      public static final String PUBLIC_ROLE_NAME
      Every user belongs to this role.
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    • SALT_LEN

      public static final int SALT_LEN
      The number of bytes in random salt that is used to hash passwords.
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    • INFORMATION_SCHEMA_ID

      public static final int INFORMATION_SCHEMA_ID
      The identity of INFORMATION_SCHEMA.
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    • MAIN_SCHEMA_ID

      public static final int MAIN_SCHEMA_ID
      The identity of PUBLIC schema.
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    • SCHEMA_MAIN

      public static final String SCHEMA_MAIN
      The name of the default schema.
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    • PG_CATALOG_SCHEMA_ID

      public static final int PG_CATALOG_SCHEMA_ID
      The identity of pg_catalog schema.
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    • SCHEMA_PG_CATALOG

      public static final String SCHEMA_PG_CATALOG
      The name of the pg_catalog schema.
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    • SELECTIVITY_DEFAULT

      public static final int SELECTIVITY_DEFAULT
      The default selectivity (used if the selectivity is not calculated).
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    • SELECTIVITY_DISTINCT_COUNT

      public static final int SELECTIVITY_DISTINCT_COUNT
      The number of distinct values to keep in memory when running ANALYZE.
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    • SERVER_PROPERTIES_DIR

      public static final String SERVER_PROPERTIES_DIR
      The default directory name of the server properties file for the H2 Console.
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    • SERVER_PROPERTIES_NAME

      public static final String SERVER_PROPERTIES_NAME
      The name of the server properties file for the H2 Console.
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    • SLOW_QUERY_LIMIT_MS

      public static final long SLOW_QUERY_LIMIT_MS
      Queries that take longer than this number of milliseconds are written to the trace file with the level info.
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    • START_URL

      public static final String START_URL
      The database URL prefix of this database.
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    • SUFFIX_LOCK_FILE

      public static final String SUFFIX_LOCK_FILE
      The file name suffix of file lock files that are used to make sure a database is open by only one process at any time.
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    • SUFFIX_OLD_DATABASE_FILE

      public static final String SUFFIX_OLD_DATABASE_FILE
      The file name suffix of a H2 version 1.1 database file.
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    • SUFFIX_MV_FILE

      public static final String SUFFIX_MV_FILE
      The file name suffix of a MVStore file.
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    • SUFFIX_MV_STORE_NEW_FILE

      public static final String SUFFIX_MV_STORE_NEW_FILE
      The file name suffix of a new MVStore file, used when compacting a store.
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    • SUFFIX_MV_STORE_TEMP_FILE

      public static final String SUFFIX_MV_STORE_TEMP_FILE
      The file name suffix of a temporary MVStore file, used when compacting a store.
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    • SUFFIX_TEMP_FILE

      public static final String SUFFIX_TEMP_FILE
      The file name suffix of temporary files.
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    • SUFFIX_TRACE_FILE

      public static final String SUFFIX_TRACE_FILE
      The file name suffix of trace files.
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    • THROTTLE_DELAY

      public static final int THROTTLE_DELAY
      How often we check to see if we need to apply a throttling delay if SET THROTTLE has been used.
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    • URL_FORMAT

      public static final String URL_FORMAT
      The database URL format in simplified Backus-Naur form.
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    • USER_PACKAGE

      public static final String USER_PACKAGE
      The package name of user defined classes.
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    • VIEW_COST_CACHE_MAX_AGE

      public static final int VIEW_COST_CACHE_MAX_AGE
      The maximum time in milliseconds to keep the cost of a view. 10000 means 10 seconds.
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    • VIEW_INDEX_CACHE_SIZE

      public static final int VIEW_INDEX_CACHE_SIZE
      The name of the index cache that is used for temporary view (subqueries used as tables).
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    • QUERY_STATISTICS_MAX_ENTRIES

      public static final int QUERY_STATISTICS_MAX_ENTRIES
      The maximum number of entries in query statistics.
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    • MIN_WEB_ADMIN_PASSWORD_LENGTH

      public static final int MIN_WEB_ADMIN_PASSWORD_LENGTH
      The minimum number of characters in web admin password.
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    • PG_VERSION

      public static final String PG_VERSION
      Announced version for PgServer.
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    • VERSION

      public static final String VERSION
      The version of this product, consisting of major version, minor version, and build id.

    • FULL_VERSION

      public static final String FULL_VERSION
      The complete version number of this database, consisting of the major version, the minor version, the build id, and the build date.