RE: Is this a performance issue?

From: Siva_Chintalapati <Siva_Chintalapati_at_satyam.com>
Date: Tue, 25 Jul 2000 23:49:49 +0530
Message-Id: <10569.112917@fatcity.com>

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What are dangling columns.

Regards
Siva

> ----------
> From: Glenn Travis[SMTP:Glenn.Travis_at_wcom.com]
> Reply To: ORACLE-L_at_fatcity.com
> Sent: Tuesday, July 25, 2000 10:27 PM
> To: Multiple recipients of list ORACLE-L
> Subject: RE: Is this a performance issue?
>
> Unless all columns can be satisfied with an index (but you already knew
> that, right?).
>
> If you have are selecting 5 columns, and say, three of them make up an
> index, you may want to consider storing the other two in the index as
> dangling columns. Depending on your table size, joins to other tables,
> performance needs, this could be a real win...
>
> > -----Original Message-----
> > From: root_at_fatcity.com [mailto:root_at_fatcity.com]On Behalf Of
> > Kamesh.J.Mantri_at_citicorp.com
> > Sent: Tuesday, July 25, 2000 5:24 AM
> > To: Multiple recipients of list ORACLE-L
> > Subject: RE: Is this a performance issue?
> >
> >
> > Actually this is not a performance issue bcos when Oracle fetches
> > rows for a
> > select it does in with implicit cursor
> > which goes row by row not column by column. Even if we mention
> > a single col
> > it fetches the whole row.
> >
> > Gurus correct me I am wrong..
> >
> >
> > Kamesh.
> >
> > -----Original Message-----
> > Sent: Monday,July 24, 2000 9:07 PM
> > To: ORACLE-L
> > Cc: schanna
> >
> >
> > Gurus,
> >
> > I'm wondering if it's a performance issue if i select all the
> > columns from
> > a table even if you don't require.
> >
> > Let say I have a table which has about 50 columns in it and i need to
> get
> > values for only 5-10 columns. So, instead of selecting only these
> columns
> > I select *.
> >
> > Any idea if that screws up my performance?
> >
> >
> >
> > Santhosh Babu
> >
> > --
> > Author: Channa, Santhosh, SITS
> > INET: schanna_at_att.com
> >
> > Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
> > San Diego, California -- Public Internet access / Mailing Lists
> > --------------------------------------------------------------------
> > To REMOVE yourself from this mailing list, send an E-Mail message
> > to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
> > the message BODY, include a line containing: UNSUB ORACLE-L
> > (or the name of mailing list you want to be removed from). You may
> > also send the HELP command for other information (like subscribing).
> >
> > --
> > Author:
> > INET: Kamesh.J.Mantri_at_citicorp.com
> >
> > Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
> > San Diego, California -- Public Internet access / Mailing Lists
> > --------------------------------------------------------------------
> > To REMOVE yourself from this mailing list, send an E-Mail message
> > to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
> > the message BODY, include a line containing: UNSUB ORACLE-L
> > (or the name of mailing list you want to be removed from). You may
> > also send the HELP command for other information (like subscribing).
> >
>
> --
> Author: Glenn Travis
> INET: Glenn.Travis_at_wcom.com
>
> Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
> San Diego, California -- Public Internet access / Mailing Lists
> --------------------------------------------------------------------
> To REMOVE yourself from this mailing list, send an E-Mail message
> to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
> the message BODY, include a line containing: UNSUB ORACLE-L
> (or the name of mailing list you want to be removed from). You may
> also send the HELP command for other information (like subscribing).
>

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What are dangling = columns.

<P><FONT COLOR=3D"#0000FF" SIZE=3D2 FACE=3D"Arial">Regards</FONT>
<BR><FONT COLOR=3D"#0000FF" SIZE=3D2 FACE=3D"Arial">Siva</FONT>
</P>
<UL>
<P><FONT SIZE=3D1 FACE=3D"MS Sans Serif">----------</FONT>
<BR><B><FONT SIZE=3D1 FACE=3D"MS Sans Serif">From:</FONT></B> &nbsp; =
<FONT SIZE=3D1 FACE=3D"MS Sans Serif">Glenn =

Travis[SMTP:Glenn.Travis_at_wcom.com] Reply To: =       ORACLE-L_at_fatcity.com
 Sent:   = Tuesday, July 25, 2000 10:27 = PM
 To: =     Multiple = recipients of list ORACLE-L
 Subject: =        RE: Is this a performance issue?

Unless all columns can be satisfied = with an index (but you already knew that, right?).

If you have are selecting 5 columns, = and say, three of them make up an index, you may want to consider = storing the other two in the index as dangling columns.  Depending on = your table size, joins to other tables, performance needs, this could be a = real win...

> -----Original Message----- > From: root_at_fatcity.com = [<A = HREF=3D"mailto:root_at_fatcity.com">mailto:root_at_fatcity.com</A><= FONT SIZE=3D2 FACE=3D"Arial">]On Behalf Of > = Kamesh.J.Mantri_at_citicorp.com
 > Sent: Tuesday, July 25, 2000 = 5:24 AM
 > To: Multiple recipients of list = ORACLE-L
 > Subject: RE: Is this a = performance issue?

<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt; Actually this is not a =

performance issue bcos when Oracle fetches > rows for a > select it does in with implicit = cursor
 > which goes row by  row not = column by column.  Even if we mention

<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt; a single col</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt; it fetches the whole row.</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt; Gurus correct me I am =

wrong..

<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt; Kamesh.</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt; -----Original =

Message-----
 > Sent: Monday,July 24, 2000 9:07 = PM

<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt; To: ORACLE-L</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt; Cc: schanna</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt; Gurus,</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;&nbsp; I'm wondering if it's a =

performance issue if i select all the > columns from >  a table even if you don't = require.
 > >  Let say I have a table = which has about 50 columns in it and i need to get >  values for only 5-10 = columns. So, instead of selecting only these columns

<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;&nbsp; I select *.</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;&nbsp; Any idea if that screws up =

my performance?

<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;&nbsp; Santhosh Babu</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt; --</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt; Author: Channa, Santhosh, =

SITS
 >   INET: = schanna_at_att.com
 > > Fat City Network = Services    -- (858) 538-5051  FAX: (858) = 538-5051
 > San Diego, = California        -- Public Internet = access / Mailing Lists
 > =

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NT>
 > To REMOVE yourself from this = mailing list, send an E-Mail message > to: ListGuru_at_fatcity.com (note = EXACT spelling of 'ListGuru') and in > the message BODY, include a line = containing: UNSUB ORACLE-L
 > (or the name of mailing list you = want to be removed from).  You may > also send the HELP command for = other information (like subscribing).

<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt; --</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt; Author:</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&gt;&nbsp;&nbsp; INET: =

Kamesh.J.Mantri_at_citicorp.com
 > > Fat City Network = Services    -- (858) 538-5051  FAX: (858) = 538-5051
 > San Diego, = California        -- Public Internet = access / Mailing Lists
 > =

--------------------------------------------------------------------</FO=

<P><FONT SIZE=3D2 FACE=3D"Arial">-- </FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">Author: Glenn Travis</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&nbsp; INET: =

Glenn.Travis_at_wcom.com

Fat City Network = Services    -- (858) 538-5051  FAX: (858) = 538-5051
 San Diego, = California        -- Public Internet = access / Mailing Lists
 <FONT SIZE=3D2 =

FACE=3D"Arial">---------------------------------------------------------=

-----------
 To REMOVE yourself from this mailing = list, send an E-Mail message
 to: ListGuru_at_fatcity.com (note EXACT = spelling of 'ListGuru') and in
 the message BODY, include a line = containing: UNSUB ORACLE-L Received on Tue Jul 25 2000 - 13:19:49 CDT