Selects Against ALL_SYNONYMS that Filter Rows Based on Attributes Such as the Synonym or Owner Name Perform Slowly
(Doc ID 1242844.1)
Last updated on FEBRUARY 14, 2019
Applies to:
Oracle Database - Enterprise Edition - Version 11.2.0.1 to 11.2.0.3 [Release 11.2]Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Information in this document applies to any platform.
Symptoms
- Poor performance may be encountered with queries against ALL_SYNONYMS that contain predicates to filter rows based on attributes such as the synonym name or owner name. For example, poor performance may be encountered when querying ALL_SYNONYMS with queries such as :
SELECT *
FROM all_synonyms
WHERE owner = '<owner>'
AND table_name = '<table-name>';or
SELECT table_name, table_owner
FROM all_synonyms
WHERE owner = 'PUBLIC'
AND synonym_name = '<synonym-name>'; - Dictionary and Fixed table statistics have been gathered and are up to date. See:
<Document 457926.1> How to gather statistics on SYS objects and fixed_objects?
<Document 798257.1> GATHER_FIXED_OBJECTS_STATS Considerations - The problem may be more noticeable if the database has been upgraded from and earlier release (e.g. between 10.2 and 11.2) but this is not a necessary symptom; the database does not have to have been upgraded.
Changes
Installation and usage of 11.2 onwards or Migration from 10.2. to 11.2.
Cause
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In this Document
Symptoms |
Changes |
Cause |
Solution |
References |