12 Administering Oracle Text

12.1 Oracle Text Users and Roles

While any user can create an Oracle Text index and enter a CONTAINS query, Oracle Text provides the CTXSYS user for administration and the CTXAPP role for application developers.

12.2 DML Queue

When there are inserts, updates, or deletes to documents in your base table, the DML queue stores the requests for documents waiting to be indexed. When you synchronize the index with CTX_DDL.SYNC_INDEX, requests are removed from this queue.

Pending DML requests can be queried with the CTX_PENDING and CTX_USER_PENDING views.

DML errors can be queried with the CTX_INDEX_ERRORS or CTX_USER_INDEX_ERRORS view.

12.3 The CTX_OUTPUT Package

Use the CTX_OUTPUT PL/SQL package to log indexing and document service requests.

12.4 The CTX_REPORT Package

Use the CTX_REPORT package to produce reports on indexes and queries. These reports can help you fine-tune or troubleshoot your applications.

The CTX_REPORT package contains the following procedures:

CTX_REPORT.DESCRIBE_INDEX

CTX_REPORT.DESCRIBE_POLICY

These procedures create reports that describe an existing index or policy, including the settings of the index metadata, the indexing objects used, the settings of the attributes of the objects, and (for CTX_REPORT.DESCRIBE_INDEX) index partition information, if any. These procedures are especially useful for diagnosing index-related problems.

This is sample output from DESCRIBE_INDEX, run on a simple context index:

=================================================================
                        INDEX DESCRIPTION
=================================================================
index name:                      "DR_TEST"."TDRBPRX0"
index id:                        1160
index type:                      context
base table:                      "DR_TEST"."TDRBPR"
primary key column:              ID
text column:                     TEXT2
text column type:                VARCHAR2(80)
language column:
format column:
charset column:
=================================================================
                          INDEX OBJECTS
=================================================================
datastore:                       DIRECT_DATASTORE
filter:                          NULL_FILTER
section group:                   NULL_SECTION_GROUP
lexer:                           BASIC_LEXER
wordlist:                        BASIC_WORDLIST
   stemmer:                         ENGLISH
   fuzzy_match:                     GENERIC
stoplist:                        BASIC_STOPLIST
   stop_word:                       teststopword
storage:                         BASIC_STORAGE
   r_table_clause:                  lob (data) store as (cache)
   i_index_clause:                  compress 2

CTX_REPORT.CREATE_INDEX_SCRIPT

CTX_REPORT.CREATE_POLICY_SCRIPT

CREATE_INDEX_SCRIPT creates a SQL*Plus script that can create a duplicate of a given text index. Use this when you have an index but don't have the original script (if any) used to create that script and want to be able to re-create the index. For example, if you accidentally drop a script, CREATE_INDEX_SCRIPT can re-create it; likewise, CREATE_INDEX_SCRIPT can be useful if you have inherited indexes from another user but not the scripts that created them.

CREATE_POLICY_SCRIPT does the same thing as CREATE_INDEX_SCRIPT, except that it enables you to re-create a policy instead of an index.

This is sample output from CREATE_INDEX_SCRIPT, run on a simple context index (not a complete listing):

begin
  ctx_ddl.create_preference('"TDRBPRX0_DST"','DIRECT_DATASTORE');
end;
/
...
/
begin
  ctx_ddl.create_section_group('"TDRBPRX0_SGP"','NULL_SECTION_GROUP');
end;
/
...
begin
  ctx_ddl.create_preference('"TDRBPRX0_WDL"','BASIC_WORDLIST');
  ctx_ddl.set_attribute('"TDRBPRX0_WDL"','STEMMER','ENGLISH');
  ctx_ddl.set_attribute('"TDRBPRX0_WDL"','FUZZY_MATCH','GENERIC');
end;
/
begin
  ctx_ddl.create_stoplist('"TDRBPRX0_SPL"','BASIC_STOPLIST');
  ctx_ddl.add_stopword('"TDRBPRX0_SPL"','teststopword');
end;
/
...
/
begin
  ctx_output.start_log('TDRBPRX0_LOG');
end;
/
create index "DR_TEST"."TDRBPRX0"
  on "DR_TEST"."TDRBPR"
      ("TEXT2")
  indextype is ctxsys.context
  parameters('
    datastore       "TDRBPRX0_DST"
    filter          "TDRBPRX0_FIL"
    section group   "TDRBPRX0_SGP"
    lexer           "TDRBPRX0_LEX"
    wordlist        "TDRBPRX0_WDL"
    stoplist        "TDRBPRX0_SPL"
    storage         "TDRBPRX0_STO"
  ')
/

CTX_REPORT.INDEX_SIZE

This procedure creates a report showing the names of the internal index objects, along with their tablespaces, allocated sizes, and used sizes. It is useful for DBAs who may need to monitor the size of their indexes (for example, when disk space is at a premium).

Sample output from this procedure looks like this (partial listing):

=================================================================
                INDEX SIZE FOR DR_TEST.TDRBPRX10
=================================================================
TABLE:                          DR_TEST.DR$TDRBPRX10$I
TABLESPACE NAME:                DRSYS
BLOCKS ALLOCATED:                                            4
BLOCKS USED:                                                 1
BYTES ALLOCATED:                               8,192 (8.00 KB)
BYTES USED:                                    2,048 (2.00 KB)

INDEX (LOB):                    DR_TEST.SYS_IL0000023161C00006$$
TABLE NAME:                     DR_TEST.DR$TDRBPRX10$I
TABLESPACE NAME:                DRSYS
BLOCKS ALLOCATED:                                            5
BLOCKS USED:                                                 2
BYTES ALLOCATED:                             10,240 (10.00 KB)
BYTES USED:                                    4,096 (4.00 KB)

INDEX (NORMAL):                 DR_TEST.DR$TDRBPRX10$X
TABLE NAME:                     DR_TEST.DR$TDRBPRX10$I
TABLESPACE NAME:                DRSYS
BLOCKS ALLOCATED:                                            4
BLOCKS USED:                                                 2
BYTES ALLOCATED:                               8,192 (8.00 KB)
BYTES USED:                                    4,096 (4.00 KB)

CTX_REPORT.INDEX_STATS

INDEX_STATS produces a variety of calculated statistics about an index, such as how many documents are indexed, how many unique tokens the index contains, average size of its tokens, fragmentation information for the index, and so on. An example of a use of INDEX_STATS might be in optimizing stoplists.

See Oracle Text Reference for an example of the output of this procedure.

CTX_REPORT.QUERY_LOG_SUMMARY

This procedure creates a report of logged queries, which you can use to perform simple analyses. With query analysis, you can find out:

• which queries were made

• which queries were successful

• which queries were unsuccessful

• how many times each query was made

You can combine these factors in various ways, such as determining the 50 most frequent unsuccessful queries made by your application.

See Oracle Text Reference for an example of the output of this procedure.

CTX_REPORT.TOKEN_INFO

TOKEN_INFO is used mainly to diagnose query problems; for instance, to check that index data is not corrupted. As an example, you can use it to find out which documents are producing unexpected or bad tokens.

CTX_REPORT.TOKEN_TYPE

This is a lookup function, used mainly as input to other functions (CTX_DDL.OPTIMIZE_INDEX, CTX_REPORT.TOKEN_INFO, and so on).

12.5 Text Manager in Oracle Enterprise Manager

Oracle Enterprise Manager provides Text Manager for configuring, maintaining, and administering Oracle Text indexes. With Text Manager you can perform all of the basic configuration and administration tasks for Oracle Text indexes. You can monitor the overall health of Text indexes for a single Oracle database instance or for the Oracle Real Application Clusters environment. Text Manager provides summaries of critical information and enables you to drill down to the level of detail that you want, to resolve issues, and to understand any actions that may need to occur. You access Text Manager by clicking the Schema tab from the database home page in Oracle Enterprise Manager, and then selecting Text Indexes under the Text Manager group. On the Text Indexes page, select an index name and click View to see information and attributes for that index.

The Text Indexes page shows the jobs that are in progress, scheduled within the last seven days, or are experiencing problems. From this page you can go to the Job Scheduler to see a summary of all jobs for this database instance, and to manage selected jobs. The online help in Oracle Enterprise Manager provides details and procedures for using each Text Manager feature.

12.6 Servers and Indexing

You index documents and enter queries with standard SQL. No server is needed for performing batch DML. You can synchronize the CONTEXT index with the CTX_DDL.SYNC_INDEX procedure, or from Text Manager in Oracle Enterprise Manager.

12.7 Database Feature Usage Tracking in Oracle Enterprise Manager

Database Feature Usage statistics in Oracle Enterprise Manager provide an approximation of how often various database features are used. Tracking this information is potentially useful for application development as well as for auditing. You access Database Feature Usage by clicking the Server tab in Oracle Enterprise Manager, and then selecting Database Feature Usage under the Database Configuration group.

The following information is gathered for Oracle Text:

• Package Usage Statistics

• Index Usage Statistics

• SQL Operator Usage Statistics

12.8 Oracle Text on Oracle Real Application Clusters

Oracle Text queries can be parallelized across Oracle RAC nodes for maximum throughput and performance for OLAP applications. You can manage Oracle Text indexes on Oracle RAC nodes with Text Manager in Oracle Enterprise Manager as described in the previous section "Text Manager in Oracle Enterprise Manager".