MYSQL教程之Blockdump - 8.x Data Segment Header ...

如果互联网服务提供商，支撑数据的云服务，或它们之间任一点网络被堵塞或中断，他们就会遇到与数据延迟或应用程序故障有关的问题。如果问题发生在企业内部，解决方案提供商可以排除故障找出原因。oracle
Subject:QREF:Blockdump-8.xDataSegmentHeaderinOracleCreationDate:25-APR-2000CACHEBLOCK:SeeNote:47132.1type:0x10=DATASEGMENTHEADER-UNLIMITEDEXTENTCONTROL:ExtentHeader::spare1:0space2:0#extents:13#blocks:1429lastmap0x00000000#maps:0offset:4128Highwater::0x020004d0ext#:12blk#:275extsize:475#blocksinseg.hdrsfreelists:5#blocksbelow:1229mapblk0x00000000offset:12Unlocked==>spare1:thisfieldisnolongerused(oldinc#,nowalways0)==>space2:thisfieldisnolongerused(oldts#,nowalways0)==>#extents:numberofextentsallocatedtosegment==>#blocks:numberofblocksallocatedtosegment==>lastmap:addressoflastextentmapblock0ifextentmapisentirelyinthesegmentheader==>#maps:numberofextentmapblock==>offset:offsettoendofextentmap==>HWMdba:addressofblockathighwatermark==>ext#:HWMextentnumberrelativetosegment==>blk#:HWMblocknumberwithinextent==>extsize:HWMextentsize(inblocks)==>#blocksinseg.hdrsfreelists:numberofblocksinseg.hdrsfreelist==>#blocksbelow:numberofblocksbelowHWM==>mapblkdba:dbaofextentmapblockcontainingHWMextentis0ifHWMisinthesegmentheader==>offset:offsetwithinextentmapblockistheext#ifHWMisinsegmentheader==>Lockedby:iflockedbyatransaction,thexidisdisplayedEXTENTMAP:MapHeader::next0x00000000#extents:13obj#:12141flag:0x400000000x02000003length:40x02000007length:50x0200000clength:100x02000016length:150x02000025length:200x02000039length:300x02000057length:450x02000084length:650x020000c5length:950x02000124length:1400x020001b0length:2100x02000282length:3150x020003bdlength:475MapHeader:==>nextdba:addressofnextextentmapblock==>#extents:numberofextentsinthisextentmapblock==>obj#:objectidforthissegment==>flag:Flagtomarktheversionofsegmentheaderis2ifthesegmentheaderisV8MapExtent:==>dba:dbaofextent==>length:numberofblocksinextentFREELIST:nfl=1,nfb=1typ=1nxf=0SEGLST::flg:USEDlhd:0x020004cbltl:0x020004cfSegmentHeader:==>nfl:numberoffreelists/block==>nfb:numberoffreelistblocks+segmentheader==>typ:blocktype==>nxf:numberoftransactionfreelistsSegmentList:==>flg:flagUSEDorUNUSEDthefreelist==>lhd:headoffreelist==>ltl:tailoffreelist
你可以配置MySQL运行在微小的嵌入式应用程序中，处理的数据可能不足1Mb??而你也可以用它来处理数Tb的数据。MySQL获得这种可扩展性的路径之一是通过一个人们所熟知的存储过程，这是一个运行在程序之外的微型、预编译程序。