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Number of fields in a table |
Thu, Dec 20 2007 11:43 AM | Permanent Link |
"Brian Kennedy" | I have a VERY wide table with approximately 150 fields. I am adding another
feature and need to add an additional 20 fields to that table. In concern for network performance, would it be better to create a separate table to store these 20 additional fields? Or, would it be safe to add these fields to the wide table provided I limit selection to the fields I need via SQL during program operation. (i.e. SELECT FIELD1, FIELD2, FIELD3 from TABLE) Thank you. Brian Kennedy DBISAM C/S 4.24 B1 |
Thu, Dec 20 2007 12:01 PM | Permanent Link |
Tim Young [Elevate Software] Elevate Software, Inc. timyoung@elevatesoft.com | Brian,
<< I have a VERY wide table with approximately 150 fields. I am adding another feature and need to add an additional 20 fields to that table. In concern for network performance, would it be better to create a separate table to store these 20 additional fields? >> I would try to add the 20 fields first and see how things go in terms of performance. You do start to see a performance decrease when record sizes start reaching 2k or so, simply because a lot of times you're reading so much data only to inspect a field or two. So, in essence, the real determining factor is not the number of fields, but rather the record size. You can see the total record size by opening the table in the DBSYS utility and viewing the Structure tab of the open table. -- Tim Young Elevate Software www.elevatesoft.com |
Fri, Dec 28 2007 10:20 AM | Permanent Link |
"Brian Kennedy" | Tim,
Thanks. Sorry for the delayed reply. I have been away for the holiday season! Hmmm...record size is currently near 4K already! So, just to clarify, even if my SQL is only pulling the fields it needs from the table (i.e. SELECT Field1, Field2, Field3 from TABLE), performance could be still affected since the table is so wide? Thanks Tim. Brian "Tim Young [Elevate Software]" <timyoung@elevatesoft.com> wrote in message news:9E88DC9F-58A9-4EA4-92D7-0CC52E873662@news.elevatesoft.com... > Brian, > > << I have a VERY wide table with approximately 150 fields. I am adding > another feature and need to add an additional 20 fields to that table. In > concern for network performance, would it be better to create a separate > table to > store these 20 additional fields? >> > > I would try to add the 20 fields first and see how things go in terms of > performance. You do start to see a performance decrease when record sizes > start reaching 2k or so, simply because a lot of times you're reading so > much data only to inspect a field or two. So, in essence, the real > determining factor is not the number of fields, but rather the record > size. You can see the total record size by opening the table in the DBSYS > utility and viewing the Structure tab of the open table. > > -- > Tim Young > Elevate Software > www.elevatesoft.com > |
Fri, Dec 28 2007 2:14 PM | Permanent Link |
Tim Young [Elevate Software] Elevate Software, Inc. timyoung@elevatesoft.com | Brian,
<< Hmmm...record size is currently near 4K already! So, just to clarify, even if my SQL is only pulling the fields it needs from the table (i.e. SELECT Field1, Field2, Field3 from TABLE), performance could be still affected since the table is so wide? >> Yes. This is one of the reasons why it is important to normalize tables as much as possible given the design/join performance considerations. -- Tim Young Elevate Software www.elevatesoft.com |
Fri, Dec 28 2007 2:30 PM | Permanent Link |
"Brian Kennedy" | Okay, thank you Tim. Not only would it probably be best to have a separate
table for the new fields, I guess it might be a good idea to also break this table up into separate tables so the record size is smaller. I could see the width of the table possibly hindering performance over lower bandwidths. Brian "Tim Young [Elevate Software]" <timyoung@elevatesoft.com> wrote in message news:129F73A2-A96D-4988-8408-996F928DAC48@news.elevatesoft.com... > Brian, > > << Hmmm...record size is currently near 4K already! So, just to clarify, > even if my SQL is only pulling the fields it needs from the table (i.e. > SELECT Field1, Field2, Field3 from TABLE), performance could be still > affected since the table is so wide? >> > > Yes. This is one of the reasons why it is important to normalize tables > as much as possible given the design/join performance considerations. > > -- > Tim Young > Elevate Software > www.elevatesoft.com > |
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