SQL Anywhere Mobile - Performance warning messages in remote database log.

Author

Performance warning messages in remote database log.

Tom Owens

2005-08-02, 1:24 pm

I see preformance warnings on the remote database log but
don't know how resolve them.
1. Page size too small.
2. Redundant index "INDEX_NAME" for table "TABLE_NAME" in
database "DATABASE_NAME".

Breck Carter [TeamSybase]

2005-08-02, 8:25 pm

On 2 Aug 2005 11:20:06 -0700, Tom Owens wrote:

>I see preformance warnings on the remote database log but
>don't know how resolve them.
>1. Page size too small.

Please show us the exact text for that one... I don't remember seeing
it on the console log.

The database page size can only be changed by creating a new database
(dbunload, dbinit, dbisql reload.sql). 4K is generally recognized as a
good value. 8K is sometimes useful. The other values are usually bad.

What version & build are you using? e.g., 9.0.2.3137

>2. Redundant index "INDEX_NAME" for table "TABLE_NAME" in
>database "DATABASE_NAME".

The message means there are two indexes on the same columns. Primary
keys, foreign keys and UNIQUE constraints all have indexes
automatically created for them; that's usually the source of redundant
indexes, if you have explicitly created indexes on the same columns.
It's not fatal, but it's a waste of space and performance. Just drop
the redundant indexes.

FWIW Foxhound explains redundant indexes in more detail; here is an
example from the Version 7 asademo.db:

-- Note: The table DBA.sales_order_items has more than one index on
-- columns ( prod_id ):
-- Non-unique index "ix_item_prod"
-- Foreign key "ky_prod_id"

The Foxhound Help goes into detail on this subject as well.

See http://www.risingroad.com/foxhound_beta_3.html

Breck

--
SQL Anywhere Studio 9 Developer's Guide
Buy the book: http://www.amazon.com/exec/obidos/A...7/risingroad-20
bcarter@risingroad.com
RisingRoad SQL Anywhere and MobiLink Professional Services
www.risingroad.com

Tom Owens

2005-08-05, 3:24 am

Breck Carter [TeamSybase] wrote:
> On 2 Aug 2005 11:20:06 -0700, Tom Owens wrote:
>
>
>
>
> Please show us the exact text for that one... I don't remember seeing
> it on the console log.
>
> The database page size can only be changed by creating a new database
> (dbunload, dbinit, dbisql reload.sql). 4K is generally recognized as a
> good value. 8K is sometimes useful. The other values are usually bad.
>
> What version & build are you using? e.g., 9.0.2.3137
>
>
>
>
> The message means there are two indexes on the same columns. Primary
> keys, foreign keys and UNIQUE constraints all have indexes
> automatically created for them; that's usually the source of redundant
> indexes, if you have explicitly created indexes on the same columns.
> It's not fatal, but it's a waste of space and performance. Just drop
> the redundant indexes.
>
> FWIW Foxhound explains redundant indexes in more detail; here is an
> example from the Version 7 asademo.db:
>
> -- Note: The table DBA.sales_order_items has more than one index on
> -- columns ( prod_id ):
> -- Non-unique index "ix_item_prod"
> -- Foreign key "ky_prod_id"
>
> The Foxhound Help goes into detail on this subject as well.
>
> See http://www.risingroad.com/foxhound_beta_3.html
>
> Breck
>
> --
> SQL Anywhere Studio 9 Developer's Guide
> Buy the book: http://www.amazon.com/exec/obidos/A...7/risingroad-20
> bcarter@risingroad.com
> RisingRoad SQL Anywhere and MobiLink Professional Services
> www.risingroad.com

The warning messages are displayed on the remote transaction log. The
remote database tables were created using the migrate wizard from an
Oracle 9i consolidated database.
Is there a way to prevent indexes from being migrated if Mobilink is
creating an index for the columns marked primary key?

David Fishburn

2005-08-08, 9:24 am

Tom Owens <towens99@comcast.net> wrote in news:42f2c3ea@forums
-2-dub of
sybase.public.sqlanywhere.mobilink:

TO> The warning messages are displayed on the remote transaction log. The
TO> remote database tables were created using the migrate wizard from an
TO> Oracle 9i consolidated database.
TO> Is there a way to prevent indexes from being migrated if Mobilink is
TO> creating an index for the columns marked primary key?

Well, you would only migrate the schema once, it is not like you do this
each and every time you run your synchronization.

Just remove the duplicate indicies.
--
David Fishburn
Certified ASA Developer Version 8
iAnywhere Solutions - Sybase
Professional Services
Please only post to the newsgroup
Please ALWAYS include version and MORE importantly BUILD number with
EACH post (dbeng9 -v).

EBFs and Maintenance Releases
http://downloads.sybase.com/swx/sdmain.stm

Developer Community / Whitepapers
http://www.ianywhere.com/developer

CaseXpress - to report bugs
http://casexpress.sybase.com

CodeXchange - Free samples
[url]http://ianywhere.codexchange.sybase.com/servlets/ ProjectDocumentList[
/url]

Sponsored Links