Hi again,
maybe you can make a whitelist (array) of views for wich you want the additional fields and check before extending the query … not too elegant, but solves the problem. BTW: if it's only one field and you do not have hundreds of categories while beeing on a samll shared host, I would not expect this to affect performance / memoryfootprint noticibly. Regards, Kai Von: [email protected] [mailto:[email protected]] Im Auftrag von Michael Zender Gesendet: Donnerstag, 24. Januar 2013 08:52 An: [email protected] Betreff: Re: [oxid-dev-general] Lazy Loading Hello Tomas and Kai, Thank you for your response guys. I already found the oxCategoryList::_getSqlSelectFieldsForTree() method and I am aware of the fact that I could override it in order to enhance the object that is loaded into the category tree. However this would result in more data being loaded on every view not just in case I need it. Initially, I was just hoping for lazy loading to jump in and lazily load the data I require on demand. Turned out, that I was wrong with my expectations. So thanks again to everyone for your help and effort! Best regards Dipl.-Ing. (FH) Michael Zender Development eCommerce Technical Project Lead MOS-TANGRAM AG Wohlerstrasse 2 CH-5623 Boswil Phone: +41 (0)56 677 82 20 Fax: +41 (0)56 677 82 99 E-Mail: <mailto:[email protected]> [email protected] Internet: <http://www.mos-tangarm.com/> http://www.mos-tangram.com Von: [email protected] [mailto:[email protected]] Im Auftrag von Kai Gazmaga Gesendet: Mittwoch, 23. Januar 2013 16:49 An: [email protected] Betreff: Re: [oxid-dev-general] Lazy Loading Hi folks, I also had that problem a few days ago - and before ;-) My simple solution looks like this: class vd_oxCategoryList extends vd_oxCategoryList_parent { protected function _getSqlSelectFieldsForTree($sTable, $aColumns = null) { $sFieldList = parent::_getSqlSelectFieldsForTree($sTable, $aColumns); $sFieldList .= ", ".$sTable.".oxlongdesc as oxlongdesc"; return $sFieldList; } } This is easy to read and extend, if you need more fields. Regards, Kai Von: [email protected] [mailto:[email protected]] Im Auftrag von Tomas Liubinas Gesendet: Mittwoch, 23. Januar 2013 16:28 An: <mailto:[email protected]> [email protected] Betreff: Re: [oxid-dev-general] Lazy Loading Hi together! There are a few aspects regarding this issue. Lazy loading is a technique ensuring that you load only needed fields instead of loading all the record information. The field list is cached per Controller. This way for example long description is not loaded in article lists as long description information is not used there. It works transparently. There is no need to take care about this aspect in templates or in the module code. As soon as you use a new field for example in your templates it is loaded in the following way: - First of all missing field triggers __get() magic getter. - The missing field is identified and the value to the object is retrieved using a separate SQL select. - The field is registered to field cache and next time it is included in needed field list and will be retrieved together with other field information for this Controller (template). Lazy loading is a generic technique implemented in oxBase class, however it is turned ON only in oxArticle object by default. Overall its implementation is a bit complex and there were ideas to get rid of it at all, but for oxArticle and oxArticleList it is still gives some performance advance. Original problem was that category tree was not loading some field values. Without deeper investigation I would say this happens not because of lazy loading problems, but because oxCategoryList::_getSqlSelectFieldsForTree() method has hardcoded list of select fields. So in order to have extended information in the tree, this method should be extended to additionally include icon field value. You mentioned there is a way to fix this problem by lazy loading setting manipulation. I guess that would work, but it must be not performance optimal. When you turn lazy laoding ON then initially the list would be loaded with missing field information and additional fields are loaded by lazy loading technique, but only on __get() magic getter. If it works like this I am happy lazy loading is robust enough to retrieve this information, but as I said this is not recommended way to do that. As I said I would recommend playing with oxCategoryList::_getSqlSelectFieldsForTree() field list :) Regards Tomas Liubinas From: [email protected] [mailto:[email protected]] On Behalf Of Michael Zender Sent: Wednesday, January 23, 2013 3:12 PM To: [email protected] Subject: Re: [oxid-dev-general] Lazy Loading Hi Tim, Thanks a lot, disabling the field caching for the respective class solved my problem. It seems to result in an additional cache file being created for the respective object and every view that uses this object (e.g. oxeec_fieldnames_oxcategories_start_i18n.txt). In the cache file all the fields are mentioned that are used to render the respective view. I still don’t understand, why lazy loading was implemented this way and why I have to disable caching to produce additional cache files that result in another feature working. In my opinion, lazy loading could be implemented non-optional, with a set of default fields for each db object. Every additional field gets loaded on demand. Additionally, this could be optimized the way it seems to be using a cache file that stores all the fields in addition to the default ones that should be loaded when a certain view is rendered. Maybe one of the core devs could say a word or two on this topic and whether this could be considered a bug in the implementation or just a small design flaw. Thanks a lot for your help! Best regards Dipl.-Ing. (FH) Michael Zender Development eCommerce Technical Project Lead MOS-TANGRAM AG Wohlerstrasse 2 CH-5623 Boswil Phone: +41 (0)56 677 82 20 Fax: +41 (0)56 677 82 99 E-Mail: <mailto:[email protected]> [email protected] Internet: <http://www.mos-tangarm.com/> http://www.mos-tangram.com Von: [email protected] [mailto:[email protected]] Im Auftrag von Tim Aniol Gesendet: Mittwoch, 23. Januar 2013 12:00 An: [email protected] Betreff: Re: [oxid-dev-general] Lazy Loading Hi Michael, we ran into the same problem with oxcategory and category descriptions for sub-categories. This code snippet works fine for us: /** * Module smx_oxcategory * Activate lazyloading to get custom db fields */ public function __construct() { $this->_blUseLazyLoading = true; self::$_blDisableFieldCaching[get_class($this)] = true; parent::__construct(); } Mit freundlichen Grüßen Tim Aniol Softwareentwickler ************************************* shoptimax GmbH Guntherstraße 45a 90461 Nürnberg Tel (09 11) 2 55 66 - 10 Fax (09 11) 2 55 66 - 29 eMail <mailto:[email protected]> [email protected] Web <http://www.shoptimax.de> www.shoptimax.de ************************************* Geschäftsführung: Friedrich Schreieck Ust.-IdNr.: DE 814340642 Amtsgericht Nürnberg HRB 21703 Von: [email protected] [mailto:[email protected]] Im Auftrag von Michael Zender Gesendet: Mittwoch, 23. Januar 2013 11:55 An: <mailto:[email protected]> [email protected] Betreff: Re: [oxid-dev-general] Lazy Loading Hi Björn, Thank you for your quick answer!! I already tried, what you suggested. Sorry, I did not mention that in my original E-Mail. I created a module for oxCategory and set oxCategory::$_blUseLazyLoading to true in the overridden init() method. Unfortunately, this does not seem to have any effect on my problem. Best regards Dipl.-Ing. (FH) Michael Zender Development eCommerce Technical Project Lead MOS-TANGRAM AG Wohlerstrasse 2 CH-5623 Boswil Phone: +41 (0)56 677 82 20 Fax: +41 (0)56 677 82 99 E-Mail: <mailto:[email protected]> [email protected] Internet: <http://www.mos-tangarm.com/> http://www.mos-tangram.com Von: [email protected] [mailto:[email protected]] Im Auftrag von Lange, Björn Gesendet: Mittwoch, 23. Januar 2013 11:40 An: [email protected] Betreff: Re: [oxid-dev-general] Lazy Loading Hi Michael, 2013/1/23 Michael Zender <[email protected]> I investigated this issue a little further and discovered, that the $oxcmp_categories object is constructed using the method oxCategoryList::buildTree() which does NOT load the oxpromoicon field for very category. BUT, as far as my understanding of lazy loading goes, the respective field should be loaded automatically, when it is accessed, but not already loaded. I would use a module till now for this use case. I hope someone can elaborate a little bit on this topic, how the lazy loading feature in OXID works and how one has to use it. Also, for a scenario like mine, what would be the best practice to get the URL I’m interested in. Lazy Loading works through the magical getter in the oxbase class. If the property $this->_blUseLazyLoading is true and the requested field is a table field of the objects core table, the value is loaded (either from the cache or the database). Take a look into oxarticle. _blUseLazyLoading is true by default. But in oxcategory, it is false by default. Try to change the value and i think (without further tests), it should work. Regards, Björn -- _________________________________ WBL Konzept GmbH Björn Simon Lange Geschäftsführender Gesellschafter Bilker Straße 34 40213 Düsseldorf Telefon: 0211 942 120 31 | Fax: 0211 942 120 32 <http://www.wbl-konzept.de/> www.wbl-konzept.de | <http://www.facebook.com/wbl.konzept> www.facebook.com/wbl.konzept | <mailto:[email protected]> [email protected]
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