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System Parameters

This section describes the Oracle Text system parameters. They fall into the following categories:

General System Parameters

When you install Oracle Text, in addition to the system-defined preferences, the following system parameters are set:

System Parameter	Description
MAX_INDEX_MEMORY	This is the maximum indexing memory that can be specified in the parameter clause of CREATE INDEX and ALTER INDEX.
DEFAULT_INDEX_MEMORY	This is the default indexing memory used with CREATE INDEX and ALTER INDEX.
LOG_DIRECTORY	This is the directory for CTX_OUTPUT log files.
CTX_DOC_KEY_TYPE	This is the default input key type, either ROWID or PRIMARY_KEY, for the CTX_DOC procedures. Set to ROWID at install time. See also: CTX_DOC. SET_KEY_TYPE .

You can view system defaults by querying the CTX_PARAMETERS view. You can change defaults using the CTX_ADM.SET_PARAMETER procedure.

Default Index Parameters

This section describes the index parameters you can use when you create context and ctxcat indexes.

CONTEXT Index Parameters

The following default parameters are used when you do not specify preferences in the parameter clause of CREATE INDEX when you create a context index. Each default parameter names a system-defined preference to use for data storage, filtering, lexing, and so on.

System Parameter	Used When	Default Value
DEFAULT_DATASTORE	No datastore preference specified in parameter clause of CREATE INDEX.	CTXSYS.DEFAULT_DATASTORE
DEFAULT_FILTER_FILE	No filter preference specified in parameter clause of CREATE INDEX, and either of the following conditions is true: Your files are stored in external files (BFILES) or You specify a datastore preference that uses FILE_DATASTORE	CTXSYS.INSO_FILTER
DEFAULT_FILTER_BINARY	No filter preference specified in parameter clause of CREATE INDEX, and Oracle detects that the text column datatype is RAW, LONG RAW, or BLOB.	CTXSYS.INSO_FILTER
DEFAULT_FILTER_TEXT	No filter preference specified in parameter clause of CREATE INDEX, and Oracle detects that the text column datatype is either LONG, VARCHAR2, VARCHAR, CHAR, or CLOB.	CTXSYS.NULL_FILTER
DEFAULT_SECTION_HTML	No section group specified in parameter clause of CREATE INDEX, and when either of the following conditions is true: Your datastore preference uses URL_DATASTORE or Your filter preference uses INSO_FILTER.	CTXSYS.HTML_SECTION_GROUP
DEFAULT_SECTION_TEXT	No section group specified in parameter clause of CREATE INDEX, and when you do not use either URL_DATASTORE or INSO_FILTER.	CTXSYS.NULL_SECTION_GROUP
DEFAULT_STORAGE	No storage preference specified in parameter clause of CREATE INDEX.	CTXSYS.DEFAULT_STORAGE
DEFAULT_LEXER	No lexer preference specified in parameter clause of CREATE INDEX.	CTXSYS.DEFAULT_LEXER
DEFAULT_STOPLIST	No stoplist specified in parameter clause of CREATE INDEX.	CTXSYS.DEFAULT_STOPLIST
DEFAULT_WORDLIST	No wordlist preference specified in parameter clause of CREATE INDEX.	CTXSYS.DEFAULT_WORDLIST

CTXCAT Index Parameters

The following default parameters are used when you create a CTXCAT index with CREATE INDEX and do not specify any parameters in the parameter string. The CTXCAT index supports only the index set, lexer, storage, stoplist, and wordlist parameters. Each default parameter names a system-defined preference.

System Parameter	Used When	Default Value
DEFAULT_CTXCAT_INDEX_SET	No index set specified in parameter clause of CREATE INDEX.
DEFAULT_CTXCAT_STORAGE	No storage preference specified in parameter clause of CREATE INDEX.	CTXSYS.DEFAULT_STORAGE
DEFAULT_CTXCAT_LEXER	No lexer preference specified in parameter clause of CREATE INDEX.	CTXSYS.DEFAULT_LEXER
DEFAULT_CTXCAT_STOPLIST	No stoplist specified in parameter clause of CREATE INDEX.	CTXSYS.DEFAULT_STOPLIST
DEFAULT_CTXCAT_WORDLIST	No wordlist preference specified in parameter clause of CREATE INDEX. Note that while you can specify a wordlist preference for CTXCAT indexes, most of the attributes do not apply, since the catsearch query language does not support wildcarding, fuzzy, and stemming. The only attribute that is useful is PREFIX_INDEX for Japanese data.	CTXSYS.DEFAULT_WORDLIST

CTXRULE Index Parameters

The following default parameters are used when you create a CTXRULE index with CREATE INDEX and do not specify any parameters in the parameter string. The CTXRULE index supports only the lexer, storage, stoplist, and wordlist parameters. Each default parameter names a system-defined preference.

System Parameter	Used When	Default Value
DEFAULT_CTXRULE_LEXER	No lexer preference specified in parameter clause of CREATE INDEX.	CTXSYS.DEFAULT_LEXER
DEFAULT_CTXRULE_STORAGE	No storage preference specified in parameter clause of CREATE INDEX.	CTXSYS.DEFAULT_STORAGE
DEFAULT_CTXRULE_STOPLIST	No stoplist specified in parameter clause of CREATE INDEX.	CTXSYS.DEFAULT_STOPLIST
DEFAULT_CTXRULE_WORDLIST	No wordlist preference specified in parameter clause of CREATE INDEX.	CTXSYS.DEFAULT_WORDLIST

Viewing Default Values

You can view system defaults by querying the CTX_PARAMETERS view. For example, to see all parameters and values, you can issue:

SQL> SELECT par_name, par_value from ctx_parameters;

Changing Default Values

You can change a default value using the CTX_ADM.SET_PARAMETER procedure to name another custom or system-defined preference to use as default.