redundant index log entries

[Former Member]

Hi. Yesterday, when connecting with one of our older sa clients, I noticed the log messages listed below. What usually causes these messages to be displayed? One developer speculated that indexing a foreign key might be the cause. No one here knows for sure. Thanks, Doug.

Pack 2, v.2825;PID=0xee8;THREAD=0x504;EXE=C:Program FilesSybaseSharedSybase Central 4.3win32scjview.exe;VERSION=9.0.2.2451;API=DBLIB;TIMEZONEADJUSTMENT=-

I. 04/03 15:10:46. Performance warning: Redundant index "xpkrpt_parmas_schedule" for table "rpt_params_schedule" in database "workprod"

I. 04/03 15:15:21. Performance warning: Redundant index "ssapproval_indx1" for table "sched_self_sched_approval" in database "workprod"

I. 04/03 15:15:21. Performance warning: Redundant index "rw_reports_pk_idx" for table "rw_reports" in database "workprod" I. 04/03 15:15:21. Performance warning: Redundant index "rw_columns_pk_idx" for table "rw_columns" in database "workprod"

I. 04/03 15:15:21. Performance warning: Redundant index "rw_columns_fk_idx1" for table "rw_columns" in database "workprod"

I. 04/03 15:15:21. Performance warning: Redundant index "tables_pk_idx" for table "tables" in database "workprod"

I. 04/03 15:15:21. Performance warning: Redundant index "table_columns_pk_idx" for table "table_columns" in database "workprod"

I. 04/03 15:16:09. Performance warning: Redundant index "XPKPRACTICE_GRP" for table "practice_grp" in database "workprod"

I. 04/03 15:16:09. Performance warning: Redundant index "rw_where_clause_ndx" for table "rw_where_clause" in database "workprod"

I. 04/03 15:10:46. Performance warning: Redundant index "xif272rpt_params_scchedule" for table "rpt_params_schedule" in database "workprod"

[VolkerBarth]

FWIW, the problem has disappeared with v10. Since then, redundant indizes are still possible but will share the same physical representation and do not cause performance implications.

To cite from the v10 What's new doc...

Support for index sharing

When you create a primary key, secondary key, foreign key, or unique constraint, you now create a logical index that points to a physical index (an actual indexing structure on disk). The database server automatically determines whether a new physical index is required to satisfy the logical index. This model allows the sharing of physical indexes and prevents the creation and maintenance of duplicate physical indexes, which wastes disk space.

[Former Member]

Indexes are automatically added to any primary key or foreign key. Therefore, there is no need to explicitly define one. If you do, however, you get this message.

From the docs:

Adaptive Server Anywhere automatically indexes primary key and foreign key columns. Thus, manually creating an index on a key column is not necessary and generally not recommended. If a column is only part of a key, an index may help.

Page 63

[former_SQLA_member1694880]

There is nothing to speculate about. Some versions ago, indexes on FKs were of help in certain circumstances. In V9, they are absolutely useless, hence the message.