BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  FieldByName          BorlandTalk.com Forum Index -> Delphi Language BASM View previous topic :: View next topic   Author Message Les Pawelczyk Guest Posted: Wed Apr 19, 2006 6:03 pm    Post subject: FieldByName In my quest to speed-up application that loads lots of data from database during start-up I took a look at TDataSet.FieldByName. It seems that it eventually finds its way to TFields.FindField which makes use of AnsiCompareText inside loop which goes through all the fields. AnsiCompareText calls CompareString which is a Windows API. I replaced AnsiCompareText with my own ASM version that uses lookup tables. It seems that FieldByName now executes 30% to 50% faster. That gives this particular application performance improvement much greater than what FastMM4 and FastMove can do combined. Anybody else curious to try it? Les. Back to top John O'Harrow Guest Posted: Wed Apr 19, 2006 7:03 pm    Post subject: Re: FieldByName "John Herbster" <herb-sci1_at_sbcglobal.net> wrote in message news:4446774b$1 (AT) newsgroups (DOT) borland.com... Quote: "Les Pawelczyk" wrote In my quest to speed-up application that loads lots of data from database during start-up I took a look at TDataSet.FieldByName. Aside from your interesting investigation, when my code would otherwise make lots of FieldByName() lookups, I declare some variables to hold the pointers to the field objects, load them with the addresses of the field objects at runtime just ofter opening the table, and then use them whenever the fields need to be referenced. --JohnH I do exactly the same - Just one call to FieldByName for each field at start-up. -- regards, John The Fastcode Project: http://www.fastcodeproject.org/ Back to top John Herbster Guest Posted: Wed Apr 19, 2006 7:03 pm    Post subject: Re: FieldByName "Les Pawelczyk" wrote Quote: In my quest to speed-up application that loads lots of data from database during start-up I took a look at TDataSet.FieldByName. Aside from your interesting investigation, when my code would otherwise make lots of FieldByName() lookups, I declare some variables to hold the pointers to the field objects, load them with the addresses of the field objects at runtime just ofter opening the table, and then use them whenever the fields need to be referenced. --JohnH Back to top John Herbster Guest Posted: Wed Apr 19, 2006 8:03 pm    Post subject: Re: FieldByName "ms" <nada (AT) notreally (DOT) net> wrote Quote: I do exactly the same - Just one call to FieldByName for each field at start-up. --Which works quite well...except when a given DB column could translate into different data-types depending on the platform (e.g., TFloatField vs. TIntegerField with MS-SQL vs. Oracle). To handle that possiblilty, I would use use TField vars to hold the object references and do appropriate checking where necessary. I usually add "{Reference Only}" comments to the pointer var declarations, just to prevent me from getting carried away when using FreeAndNil() when coding the cleanups. --JohnH Back to top ms Guest Posted: Wed Apr 19, 2006 8:03 pm    Post subject: Re: FieldByName Quote: I do exactly the same - Just one call to FieldByName for each field at start-up. --Which works quite well...except when a given DB column could translate into different data-types depending on the platform (e.g., TFloatField vs. TIntegerField with MS-SQL vs. Oracle). Back to top Les Pawelczyk Guest Posted: Wed Apr 19, 2006 9:03 pm    Post subject: Re: FieldByName Quote: Aside from your interesting investigation, when my code would otherwise make lots of FieldByName() lookups, I declare some variables to hold the pointers to the field objects, load them with the addresses of the field objects at runtime just ofter opening the table, and then use them whenever the fields need to be referenced. --JohnH I have a TParent object that opens the query and for each record it creates the TChild object and calls TChild.Load method passing query as parameter. Creating temp TField variables in TChild makes no sense - they are only read from once. Creating and maintaining them in TParent (up to 50 fields * 15 parent objects) would complicate existing code and future maintenance of it. First - they would have to be passed to TChild.Load method (which is virtual), second - they would have to be maintained every time a new field is added to db table (which happens often enough). Not worth any speed improvement IMO. Les. Back to top Darryl Strickland Guest Posted: Thu Apr 20, 2006 5:03 am    Post subject: Re: FieldByName Les, I would like to have a look at it to try with several of my applications. Could you upload it to the attachments group. Thanks Darryl Strickland Les Pawelczyk wrote: Quote: In my quest to speed-up application that loads lots of data from database during start-up I took a look at TDataSet.FieldByName. It seems that it eventually finds its way to TFields.FindField which makes use of AnsiCompareText inside loop which goes through all the fields. AnsiCompareText calls CompareString which is a Windows API. I replaced AnsiCompareText with my own ASM version that uses lookup tables. It seems that FieldByName now executes 30% to 50% faster. That gives this particular application performance improvement much greater than what FastMM4 and FastMove can do combined. Anybody else curious to try it? Les. Back to top Eric Grange Guest Posted: Thu Apr 20, 2006 7:03 am    Post subject: Re: FieldByName Quote: It seems that FieldByName now executes 30% to 50% faster. I usually just have one FieldByName call per field, after the 'Open', and place its result in a TField variable that I just use afterward (so no further field lookup or string searches in the per-record code). Wasn't there a fast AnsiCompareText challenge discussed sometime ago? This function is used in a variety of code, could be worth investigating again in a general context (we already patch it to a faster version @work, though that was after bumping on performance issues when sorting large listviews/grid-like components). Eric Back to top Guest Posted: Thu Apr 20, 2006 10:04 am    Post subject: Re: FieldByName This sounds very nice, would it be possible to share your code so I can try to use it in an application of mine? I could also try to look at how to maybe improve it a little more.. Thanks in advance, (you can mail the code to gekindekop (AT) _NO_SPAMMM_gmail (DOT) com) (offcourse removing the _NO_SPAMM_) Back to top Carsten Schuette Guest Posted: Thu Apr 20, 2006 11:03 am    Post subject: Re: FieldByName Les Pawelczyk wrote: Quote: makes use of AnsiCompareText inside loop which goes through all the fields. AnsiCompareText calls CompareString which is a Windows API. I You are right. In im opinion it is also a serious bug to call AnsiCompareText in FieldByName. The field name is usually not localized, also the strings in "FieldByName" are not localized. So they should not be compared with "AnsiCompareText", but with "CompareText". Carsten Back to top Eric Grange Guest Posted: Thu Apr 20, 2006 1:03 pm    Post subject: Re: FieldByName Quote: The field name is usually not localized If only... I've seen more localized db field names than I would have desired, with accentuated characters and other strange things in field or table names, admittedly mostly in "beginner" databases (MSAccess and MSSQL), but still... If you honour case-insensitivity for ASCII characters, you have to honour it for accentuated characters too (among others), which are part of the locale. Eric Back to top Les Pawelczyk Guest Posted: Thu Apr 20, 2006 3:03 pm    Post subject: Re: FieldByName Quote: Could you upload it to the attachments group. I might not be able to do that since some of it was developed on company time, but isn't there FastCode AnsiCompareText? If so, then it could be used as a replacement the same way FastMove replaces System.Move. Les. Back to top Frederico Pissarra Guest Posted: Sun Apr 23, 2006 9:52 am    Post subject: Re: FieldByName "John Herbster" <herb-sci1_at_sbcglobal.net> wrote in message news:44468765$1 (AT) newsgroups (DOT) borland.com... Quote: "ms" <nada (AT) notreally (DOT) net> wrote I do exactly the same - Just one call to FieldByName for each field at start-up. --Which works quite well...except when a given DB column could translate into different data-types depending on the platform (e.g., TFloatField vs. TIntegerField with MS-SQL vs. Oracle). To handle that possiblilty, I would use use TField vars to hold the object references and do appropriate checking where necessary. I usually add "{Reference Only}" comments to the pointer var declarations, just to prevent me from getting carried away when using FreeAndNil() when coding the cleanups. --JohnH I think is cheaper to use Fields property instead searching for a field that you know the actual relative position on a query: SELECT A, B, C FROM Table Fields[0] is Field A, Fields[1] is B... This way is faster, isn't it? []s Fred Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         BorlandTalk.com Forum Index -> Delphi Language BASM All times are GMT Page 1 of 1   Jump to: Select a forum C++ Builder Newsgroups----------------C++ BuilderC++ Builder (ActiveX)C++ Builder (Announcements)C++ Builder (Command Line Tools)C++ Builder DatabasesC++ Builder Databases (ADO)C++ Builder Databases (Desktop)C++ Builder Databases (InterBase Express)C++ Builder Databases (Multi-Tier)C++ Builder Databases (SQL Servers)C++ Builder (Graphics)C++ Builder (IDE)C++ Builder (Internet)C++ Builder (Internet Socket)C++ Builder (Internet Web)C++ Builder (Jobs)C++ Builder (Language)C++ Builder (Language C++)C++ Builder (Compatibility with MFC)C++ Builder (Native API)C++ Builder (Non-Technical)C++ Builder (Students)C++ Builder (Third Party Tools)C++ Builder (Upgrade)C++ Builder (VCL)C++ Builder (VCL Components Usage)C++ Builder (VCL Components Development)C++ Builder (VCL Usage)C++ Builder (WinAPI)C++ Builder Installation Delphi Newsgroups----------------Delphi (General)Delphi ActiveX Controls UsageDelphi ActiveX Controls DevelopmentDelphi As400Delphi DatabasesDelphi Databases (ADO)Delphi Databases (dbExpress)Delphi Databases (Desktop)Delphi Databases (InterBase Express)Delphi Databases (Multi-Tier)Delphi Databases (SQL Servers)Delphi DeploymentDelphi GraphicsDelphi IDEDelphi InternationalizationDelphi InternetDelphi Internet Isapi-WebBrokerDelphi Internet WebSnapDelphi Internet WinsockDelphi JobsDelphi Language BASMDelphi Language ObjectPascalDelphi Model Driven Architecture (General)Delphi Model Driven Architecture (Third Party)Delphi MultimediaDelphi Native APIDelphi Non-TechnicalDelphi ObjectPascalDelphi OLE AutomationDelphi OO designDelphi OpenToolsAPIDelphi Reporting-ChartingDelphi RTLDelphi StudentsDelphi TeamSourceDelphi Thirdparty ToolsDelphi Thirdparty Tools (General)Delphi Thirdparty Tools (IntraWeb)Delphi Thirdparty Tools (RaveReports)Delphi UpgradeDelphi VCLDelphi VCL ComponentsDelphi VCL Components UsingDelphi VCL Components WritingDelphi WebServices SOAPDelphi WinAPIDelphi XMLDelphi Installationcomp.lang.pascal.delphi.components.misccomp.lang.pascal.delphi.components.usagecomp.lang.pascal.delphi.components.writingcomp.lang.pascal.delphi.databasescomp.lang.pascal.delphi.misccomp.sources.delphi JBuilder Newsgroups----------------JBuilderJBuilder AnnouncementsJBuilder Applet IssuesJBuilder As400JBuilder CompilerJBuilder CORBA/RMIJBuilder DatabasesJBuilder DB SwingJBuilder DebuggerJBuilder DeploymentJBuilder DocumentationJBuilder EnterpriseJBuilder HandheldJBuilder IDEJBuilder JavaJBuilder JavaAPIJBuilder Java LanguageJBuilder Java SwingJBuilder Java BeansJBuilder Java Beans UsageJBuilder Java Beans DevelopmentJBuilder JBCLJBuilder JDataStoreJBuilder JobsJBuilder LinuxJBuilder MacintoshJBuilder & MobileSetJBuilder MultiLingual AppsJBuilder Non-TechnicalJBuilder OpenToolsJBuilder Servlets (JSP)JBuilder StudentsJBuilder Team DevelopmentJBuilder Thirdparty ToolsJBuilder UpgradeJBuilder Installation InterBase Newsgroups----------------InterBaseInterBase Bug DiscussionInterBase GeneralInterBase IBConsoleInterBase OpenSourceInterBase ReplicationInterBase SQLInterBase ThirdpartyInterBase Installation Miscellaneous Borland Newsgroups----------------AppCenterAppServerEnteraVisiBroker  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.