supesite完美实现调用资讯显示缩略图.doc

supesite完美实现调用资讯显示缩略图本调用代码用于放置在首页中，列表模块带缓存，每个分页的缓存时间相差20秒，避免同一时间所有缓存全部失效，某一时刻非常缓慢的问题。列表数量统计的模块也带缓存。取所有频道的资讯文章，有缩略图显示缩略图，无缩略图显示无缩略图的文件。对比嵌套循环查询，极大减少数据库查询次数(嵌套查询可能达到11次数据库查询)，本方法只需查询一次数据库。列表模块对应的sql语句为select i.itemid,i.catid,i.uid,i.username,i.subject,i.dateline,i.viewnum,i.replynum,i.digest,i.top,i.picid,,n.message,a.thumbpath,a.subject as a_subject from supe_spaceitems iinner join supe_spacenews non i.itemid=n.itemid inner join supe_categories con i.catid=c.catid left join supe_attachments aon i.picid=a.aid where i.type=newsorder by i.top desc,i.itemid desc两个inner join内联一个left join左连接做四表联查，全部为主键或者索引查询，相对效率高。由于用了联查，block模块中的perpage分页代码无效，只能自己调用multi函数处理分页内容。分页数量统计对应的sql语句为select count(itemid)as total fromsupe_spaceitemswhere type=newscachename缓存以mynews_pagexx命名的变量，解决缓存覆盖问题。supesite 7.5，256m内存vps服务器在每秒1000次并发压力下，关闭缓存平均页面执行时间为0.08秒，开启缓存平均0.006秒执行时间。完整调用代码如下：！-article begin-div class=article！-eval$basecachetime=3500；/*设置本页面基础缓存时间*/-！-eval$baseperpage=10；/*设置本页面的单页文章数量*/-！-eval$mypage=$_sgetpage?$_sgetpage：1；-！-eval$mystart=($mypage-1)*$baseperpage-！-eval$mycachename=mynews_page.$mypage-！-eval$mycachetime=$basecachetime+$mystart*2-！-block name=spacenewsparameter=type/news/sql/select%20i.itemid%2c%20i.catid%2c%20i.uid%2c%20i.username%2c%20i.subject%2c%20i.dateline%2c%20i.viewnum%2c%20i.replynum%2c%20i.digest%2c%20i.top%2c%20i.picid%2c%20%2c%20n.message%2c%20a.thumbpath%2c%20a.subject%20as%20a_subject%0d%0afrom%20supe_spaceitems%20i%0d%0ainner%20join%20supe_spacenews%20n%20on%20i.itemid%20%3d%20n.itemid%0d%0ainner%20join%20supe_categories%20c%20on%20i.catid%20%3d%20c.catid%0d%0aleft%20join%20supe_attachments%20a%20on%20i.picid%20%3d%20a.aid%0d%0aorder%20by%20i.top%20desc%2c%20i.itemid%20desc/limit/$mystart,$baseperpage/cachename/$mycachename/cachetime/$mycachetime/tpl/data-！-thiese block had cached in dollar_sblock$mycachename-！-loop$_sblock$mycachename$value-！-eval$valuemessage=trim(strip_tags($valuemessage)；-！-eval$valuemessage=trim(cutstr($valuemessage,290,1)；-！-if$valuetop-！-eval$valuesubject=置顶.$valuetop.$valuesubject；-！-/if-！-if$valuedigest-！-eval$valuesubject.=精华.$valuedigest.；-！-/if-div class=posth2 ahref=title=$valuesubject$valuesubject/a/h2 span class=pcommentsem$valuereplynum/em个评论/span div class=clear/div！-if$valuethumbpath-a href=img src=title=$valuea_subjectalt=$valuea_subjectclass=thumb_image/a！-else-a href=img src=title=$valuesubjectalt=$valuesubjectclass=thumb_image/a！-/if-div class=pcontent$valuemessage/div div class=clear/div div class=pmeta#date(y-m-d,$valuedateline)#/a href=title=$valuename$valuename/a/$valueviewnum浏览/div ahref=title=阅读全文class=readmore阅读全文/a/div！-/loop-！-navigation begin-div class=page_navi！-翻页输出控制-！-eval$mylistcount=1；-！-block name=categoryparameter=sql/select%20count%28%20itemid%20%29%20as%20total%20from%20%60supe_spaceitems%60/limit/1/cachetime/$basecachetime/cachename/indexcount/tpl/data-！-index listcount has cached in mylistcount-！-eval$mylistcount=$_sblockindexcount0total；-！-if$mylistcount-！-eval$_sgetaction=index；-！-eval$myurlarr=$_sget；-！-eval unset($myurlarrpage)；-！-eval$_sblockmynews_multi