RE: Question about sequential scans
It's all just one run of onstat. Having filtered out records for other
tables, today's output (so far) looks like this:
Partition profiles
partnum lkrqs lkwts dlks touts isrd iswrt isrwt isdel bfrd bfwrt
seqsc rhitratio
0x800161 692430 0 0 0 16947113 2041 9724 429 43323655
16881 4703 100
0xc00017 684558 0 0 0 16897256 2059 9910 445 28204359
17075 2 100
The wrapping may make this look a little awkward, but the point is that
the seqsc value is 4703 in one partition and 2 in the other. The schema
(minus fields) looks like this:
CREATE TABLE "dba".inv_billacts (
...
) WITH ROWIDS
FRAGMENT BY ROUND ROBIN IN
data01,
data02
EXTENT SIZE 5500928 NEXT SIZE 550912 LOCK MODE ROW;
I did note that not all the indices on this table are explicitly
detached (some are). I thought, though, that in 9.4+ all indices would
be in their own tblspace by default. I would think that attached indices
might produce this, however, if full index scans were being counted?
Could the rowids be doing it?
DC
> -----Original Message-----
> From: informix-list-bounces@iiug.org [mailto:informix-list-
> bounces@iiug.org] On Behalf Of bozon
> Sent: Wednesday, August 02, 2006 6:39 AM
> To: informix-list@iiug.org
> Subject: Re: Question about sequential scans
>
> Did someone clear stats between runs with onstat -z?
>
> Can you send more detail?
>
> Doug Conrey wrote:
> > We're running IDS 9.4.FC5 on AIX 5.2. I have a table that is
fragmented
> > by round robin in two dbspaces. It does have rowids (not my
decision),
> > and a number of indices. I've been noticing that the onstat -g ppf
> > output for the two partitions have wildly different numbers of
> > sequential scans. Today, for instance, one partition has 11,000 or
so,
> > the other has 2. How does that make any sense? Surely in a round
robin
> > environment if you scan one side you will also have to scan the
other.
> > This table has a pretty large number of records, so I'd like to
figure
> > out what this means. Any ideas? Thanks.
> >
> >
> >
> > DC
> >
> >
> > ------_=_NextPart_001_01C6B5B1.B0E585CC
> > Content-Type: text/html
> > Content-Transfer-Encoding: quoted-printable
> > X-Google-AttachSize: 1998
> >
> > <html xmlns:o="urn:schemas-microsoft-com:office:office"
> xmlns:w="urn:schemas-microsoft-com:office:word"
> xmlns="http://www.w3.org/TR/REC-html40">;
> >
> > <head>
> > <META HTTP-EQUIV="Content-Type" CONTENT="text/html;
charset=us-ascii">
> > <meta name=Generator content="Microsoft Word 11 (filtered medium)">
> > <style>
> > <!--
> > /* Style Definitions */
> > p.MsoNormal, li.MsoNormal, div.MsoNormal
> > {margin:0in;
> > margin-bottom:.0001pt;
> > font-size:12.0pt;
> > font-family:"Times New Roman";}
> > a:link, span.MsoHyperlink
> > {color:blue;
> > text-decoration:underline;}
> > a:visited, span.MsoHyperlinkFollowed
> > {color:purple;
> > text-decoration:underline;}
> > span.EmailStyle17
> > {mso-style-type:personal-compose;
> > font-family:Arial;
> > color:windowtext;}
> > @page Section1
> > {size:8.5in 11.0in;
> > margin:1.0in 1.25in 1.0in 1.25in;}
> > div.Section1
> > {page:Section1;}
> > -->
> > </style>
> >
> > </head>
> >
> > <body lang=EN-US link=blue vlink=purple>
> >
> > <div class=Section1>
> >
> > <p class=MsoNormal><font size=2 face=Arial><span style='font-
> size:10.0pt;
> > font-family:Arial'>We’re running IDS 9.4.FC5 on AIX 5.2. I
have a
> table
> > that is fragmented by round robin in two dbspaces. It does have
rowids
> (not my
> > decision), and a number of indices. I’ve been noticing that
the
> onstat –g
> > ppf output for the two partitions have wildly different numbers of
> sequential
> > scans. Today, for instance, one partition has 11,000 or so, the
other
> has 2.
> > How does that make any sense? Surely in a round robin environment if
you
> scan
> > one side you will also have to scan the other. This table has a
pretty
> large
> > number of records, so I’d like to figure out what this means.
Any
> ideas?
> > Thanks.<o:p></o:p></span></font></p>
> >
> > <p class=MsoNormal><font size=2 face=Arial><span style='font-
> size:10.0pt;
> > font-family:Arial'><o:p> </o:p></span></font></p>
> >
> > <p class=MsoNormal><font size=2 face=Arial><span style='font-
> size:10.0pt;
> > font-family:Arial'>DC<o:p></o:p></span></font></p>
> >
> > </div>
> >
> > </body>
> >
> > </html>
> >
> > ------_=_NextPart_001_01C6B5B1.B0E585CC--
>
> _______________________________________________
> Informix-list mailing list
> Informix-list@iiug.org
> http://www.iiug.org/mailman/listinfo/informix-list
How many records are in each partnum?
Doug Conrey wrote:
> It's all just one run of onstat. Having filtered out records for other
> tables, today's output (so far) looks like this:
>
> Partition profiles
> partnum lkrqs lkwts dlks touts isrd iswrt isrwt isdel bfrd bfwrt
> seqsc rhitratio
> 0x800161 692430 0 0 0 16947113 2041 9724 429 43323655
> 16881 4703 100
> 0xc00017 684558 0 0 0 16897256 2059 9910 445 28204359
> 17075 2 100
>
> The wrapping may make this look a little awkward, but the point is that
> the seqsc value is 4703 in one partition and 2 in the other. The schema
> (minus fields) looks like this:
>
> CREATE TABLE "dba".inv_billacts (
> ...
> ) WITH ROWIDS
> FRAGMENT BY ROUND ROBIN IN
> data01,
> data02
> EXTENT SIZE 5500928 NEXT SIZE 550912 LOCK MODE ROW;
>
> I did note that not all the indices on this table are explicitly
> detached (some are). I thought, though, that in 9.4+ all indices would
> be in their own tblspace by default. I would think that attached indices
> might produce this, however, if full index scans were being counted?
> Could the rowids be doing it?
>
> DC
>
> > -----Original Message-----
> > From: informix-list-bounces@iiug.org [mailto:informix-list-
> > bounces@iiug.org] On Behalf Of bozon
> > Sent: Wednesday, August 02, 2006 6:39 AM
> > To: informix-list@iiug.org
> > Subject: Re: Question about sequential scans
> >
> > Did someone clear stats between runs with onstat -z?
> >
> > Can you send more detail?
> >
> > Doug Conrey wrote:
> > > We're running IDS 9.4.FC5 on AIX 5.2. I have a table that is
> fragmented
> > > by round robin in two dbspaces. It does have rowids (not my
> decision),
> > > and a number of indices. I've been noticing that the onstat -g ppf
> > > output for the two partitions have wildly different numbers of
> > > sequential scans. Today, for instance, one partition has 11,000 or
> so,
> > > the other has 2. How does that make any sense? Surely in a round
> robin
> > > environment if you scan one side you will also have to scan the
> other.
> > > This table has a pretty large number of records, so I'd like to
> figure
> > > out what this means. Any ideas? Thanks.
> > >
> > >
> > >
> > > DC
> > >
> > >
> > > ------_=_NextPart_001_01C6B5B1.B0E585CC
> > > Content-Type: text/html
> > > Content-Transfer-Encoding: quoted-printable
> > > X-Google-AttachSize: 1998
> > >
> > > <html xmlns:o="urn:schemas-microsoft-com:office:office"
> > xmlns:w="urn:schemas-microsoft-com:office:word"
> > xmlns="http://www.w3.org/TR/REC-html40">;
> > >
> > > <head>
> > > <META HTTP-EQUIV="Content-Type" CONTENT="text/html;
> charset=us-ascii">
> > > <meta name=Generator content="Microsoft Word 11 (filtered medium)">
> > > <style>
> > > <!--
> > > /* Style Definitions */
> > > p.MsoNormal, li.MsoNormal, div.MsoNormal
> > > {margin:0in;
> > > margin-bottom:.0001pt;
> > > font-size:12.0pt;
> > > font-family:"Times New Roman";}
> > > a:link, span.MsoHyperlink
> > > {color:blue;
> > > text-decoration:underline;}
> > > a:visited, span.MsoHyperlinkFollowed
> > > {color:purple;
> > > text-decoration:underline;}
> > > span.EmailStyle17
> > > {mso-style-type:personal-compose;
> > > font-family:Arial;
> > > color:windowtext;}
> > > @page Section1
> > > {size:8.5in 11.0in;
> > > margin:1.0in 1.25in 1.0in 1.25in;}
> > > div.Section1
> > > {page:Section1;}
> > > -->
> > > </style>
> > >
> > > </head>
> > >
> > > <body lang=EN-US link=blue vlink=purple>
> > >
> > > <div class=Section1>
> > >
> > > <p class=MsoNormal><font size=2 face=Arial><span style='font-
> > size:10.0pt;
> > > font-family:Arial'>We’re running IDS 9.4.FC5 on AIX 5.2. I
> have a
> > table
> > > that is fragmented by round robin in two dbspaces. It does have
> rowids
> > (not my
> > > decision), and a number of indices. I’ve been noticing that
> the
> > onstat –g
> > > ppf output for the two partitions have wildly different numbers of
> > sequential
> > > scans. Today, for instance, one partition has 11,000 or so, the
> other
> > has 2.
> > > How does that make any sense? Surely in a round robin environment if
> you
> > scan
> > > one side you will also have to scan the other. This table has a
> pretty
> > large
> > > number of records, so I’d like to figure out what this means.
> Any
> > ideas?
> > > Thanks.<o:p></o:p></span></font></p>
> > >
> > > <p class=MsoNormal><font size=2 face=Arial><span style='font-
> > size:10.0pt;
> > > font-family:Arial'><o:p> </o:p></span></font></p>
> > >
> > > <p class=MsoNormal><font size=2 face=Arial><span style='font-
> > size:10.0pt;
> > > font-family:Arial'>DC<o:p></o:p></span></font></p>
> > >
> > > </div>
> > >
> > > </body>
> > >
> > > </html>
> > >
> > > ------_=_NextPart_001_01C6B5B1.B0E585CC--
> >
> > _______________________________________________
> > Informix-list mailing list
> > Informix-list@iiug.org
> > http://www.iiug.org/mailman/listinfo/informix-list
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