DbSettingsThis class contains various database-level settings. To override the documented default value for a database, append the setting in the database URL: "jdbc:h2:./test;ALIAS_COLUMN_NAME=TRUE" when opening the first connection to the database. The settings can not be changed once the database is open.Some settings are a last resort and temporary solution to work around a problem in the application or database engine. Also, there are system properties to enable features that are not yet fully tested or that are not backward compatible. aliasColumnNameDatabase setting
ALIAS_COLUMN_NAME (default: false).When enabled, aliased columns (as in SELECT ID AS I FROM TEST) return the alias (I in this case) in ResultSetMetaData.getColumnName() and 'null' in getTableName(). If disabled, the real column name (ID in this case) and table name is returned. This setting only affects the default and the MySQL mode. When using any other mode, this feature is enabled for compatibility, even if this database setting is not enabled explicitly. analyzeAutoDatabase setting
ANALYZE_AUTO (default: 2000).After changing this many rows, ANALYZE is automatically run for a table. Automatically running ANALYZE is disabled if set to 0. If set to 1000, then ANALYZE will run against each user table after about 1000 changes to that table. The time between running ANALYZE doubles each time since starting the database. It is not run on local temporary tables, and tables that have a trigger on SELECT. analyzeSampleDatabase setting
ANALYZE_SAMPLE (default: 10000).The default sample size when analyzing a table. caseInsensitiveIdentifiersDatabase setting
CASE_INSENSITIVE_IDENTIFIERS (default:
false).When set to true, all identifier names (table names, column names) are case insensitive. Setting this to "true" is experimental. compressDataDatabase setting
COMPRESS
(default: false).Compress data when storing. databaseToLowerDatabase setting
DATABASE_TO_LOWER (default: false).When set to true unquoted identifiers and short name of database are converted to lower case. Value of this setting should not be changed after creation of database. Setting this to "true" is experimental. databaseToUpperDatabase setting
DATABASE_TO_UPPER (default: true).When set to true unquoted identifiers and short name of database are converted to upper case. dbCloseOnExitDatabase setting
DB_CLOSE_ON_EXIT (default: true).Close the database when the virtual machine exits normally, using a shutdown hook. defaultConnectionDatabase setting
DEFAULT_CONNECTION (default: false).Whether Java functions can use DriverManager.getConnection("jdbc:default:connection") to
get a database connection. This feature is disabled by default for
performance reasons. Please note the Oracle JDBC driver will try to
resolve this database URL if it is loaded before the H2 driver.defaultEscapeDatabase setting
DEFAULT_ESCAPE (default: \).The default escape character for LIKE comparisons. To select no escape character, use an empty string. defaultTableEngineDatabase setting
DEFAULT_TABLE_ENGINE
(default: null).The default table engine to use for new tables. defragAlwaysDatabase setting
DEFRAG_ALWAYS (default: false).Each time the database is closed normally, it is fully defragmented (the same as SHUTDOWN DEFRAG). If you execute SHUTDOWN COMPACT, then this setting is ignored. dropRestrictDatabase setting
DROP_RESTRICT (default: true).Whether the default action for DROP TABLE, DROP VIEW, DROP SCHEMA, and DROP DOMAIN is RESTRICT. earlyFilterDatabase setting
EARLY_FILTER (default: false).This setting allows table implementations to apply filter conditions early on. estimatedFunctionTableRowsDatabase setting
ESTIMATED_FUNCTION_TABLE_ROWS (default:
1000).The estimated number of rows in a function table (for example, CSVREAD or FTL_SEARCH). This value is used by the optimizer. functionsInSchemaDatabase setting
FUNCTIONS_IN_SCHEMA
(default: true).If set, all functions are stored in a schema. Specially, the SCRIPT statement will always include the schema name in the CREATE ALIAS statement. This is not backward compatible with H2 versions 1.2.134 and older. ignoreCatalogsDatabase setting
IGNORE_CATALOGS
(default: false).If set, all catalog names in identifiers are silently accepted without comparing them with the short name of the database. lobTimeoutDatabase setting
LOB_TIMEOUT (default: 300000,
which means 5 minutes).The number of milliseconds a temporary LOB reference is kept until it times out. After the timeout, the LOB is no longer accessible using this reference. maxCompactCountDatabase setting
MAX_COMPACT_COUNT
(default: Integer.MAX_VALUE).The maximum number of pages to move when closing a database. maxCompactTimeDatabase setting
MAX_COMPACT_TIME (default: 200).The maximum time in milliseconds used to compact a database when closing. maxQueryTimeoutDatabase setting
MAX_QUERY_TIMEOUT (default: 0).The maximum timeout of a query in milliseconds. The default is 0, meaning no limit. Please note the actual query timeout may be set to a lower value. mvStoreDatabase setting
MV_STORE
(default: true).Use the MVStore storage engine. optimizeDistinctDatabase setting
OPTIMIZE_DISTINCT (default: true).Improve the performance of simple DISTINCT queries if an index is available for the given column. The optimization is used if:
optimizeEvaluatableSubqueriesDatabase setting
OPTIMIZE_EVALUATABLE_SUBQUERIES (default:
true).Optimize subqueries that are not dependent on the outer query. optimizeInListDatabase setting
OPTIMIZE_IN_LIST (default: true).Optimize IN(...) and IN(SELECT ...) comparisons. This includes optimization for SELECT, DELETE, and UPDATE. optimizeInSelectDatabase setting
OPTIMIZE_IN_SELECT (default: true).Optimize IN(SELECT ...) comparisons. This includes optimization for SELECT, DELETE, and UPDATE. optimizeInsertFromSelectDatabase setting
OPTIMIZE_INSERT_FROM_SELECT
(default: true).Insert into table from query directly bypassing temporary disk storage. This also applies to create table as select. optimizeOrDatabase setting
OPTIMIZE_OR (default: true).Convert (C=? OR C=?) to (C IN(?, ?)). optimizeTwoEqualsDatabase setting
OPTIMIZE_TWO_EQUALS (default: true).Optimize expressions of the form A=B AND B=1. In this case, AND A=1 is added so an index on A can be used. optimizeUpdateDatabase setting
OPTIMIZE_UPDATE (default: true).Speed up inserts, updates, and deletes by not reading all rows from a page unless necessary. pageStoreInternalCountDatabase setting
PAGE_STORE_INTERNAL_COUNT
(default: false).Update the row counts on a node level. pageStoreMaxGrowthDatabase setting
PAGE_STORE_MAX_GROWTH
(default: 128 * 1024).The maximum number of pages the file grows at any time. pageStoreTrimDatabase setting
PAGE_STORE_TRIM (default: true).Trim the database size when closing. queryCacheSizeDatabase setting
QUERY_CACHE_SIZE (default: 8).The size of the query cache, in number of cached statements. Each session has it's own cache with the given size. The cache is only used if the SQL statement and all parameters match. Only the last returned result per query is cached. The following statement types are cached: SELECT statements are cached (excluding UNION and FOR UPDATE statements), CALL if it returns a single value, DELETE, INSERT, MERGE, UPDATE, and transactional statements such as COMMIT. This works for both statements and prepared statement. recompileAlwaysDatabase setting
RECOMPILE_ALWAYS (default: false).Always recompile prepared statements. reuseSpaceDatabase setting
REUSE_SPACE (default: true).If disabled, all changes are appended to the database file, and existing content is never overwritten. This setting has no effect if the database is already open. shareLinkedConnectionsDatabase setting
SHARE_LINKED_CONNECTIONS
(default: true).Linked connections should be shared, that means connections to the same database should be used for all linked tables that connect to the same database. |