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  • MINSCN?Cache Fusion Read Consistent

    - by Liu Maclean(???)
    ????? ???Ask Maclean Home ???  RAC ? Past Image PI????, ?????????,???11.2.0.3 2 Node RAC??????????: SQL> select * from v$version; BANNER -------------------------------------------------------------------------------- Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production PL/SQL Release 11.2.0.3.0 - Production CORE 11.2.0.3.0 Production TNS for Linux: Version 11.2.0.3.0 - Production NLSRTL Version 11.2.0.3.0 - Production SQL> select * from global_name; GLOBAL_NAME -------------------------------------------------------------------------------- www.oracledatabase12g.com SQL> drop table test purge; Table dropped. SQL> alter system flush buffer_cache; System altered. SQL> create table test(id number); insert into test values(1); insert into test values(2); commit; /* ???? rowid??TEST????2????????? */ select dbms_rowid.rowid_block_number(rowid),dbms_rowid.rowid_relative_fno(rowid) from test; DBMS_ROWID.ROWID_BLOCK_NUMBER(ROWID) DBMS_ROWID.ROWID_RELATIVE_FNO(ROWID) ------------------------------------ ------------------------------------                                89233                                    1                                89233                                    1 SQL> alter system flush buffer_cache; System altered. Instance 1 Session A ??UPDATE??: SQL> update test set id=id+1 where id=1; 1 row updated. Instance 1 Session B ??x$BH buffer header?? ?? ??Buffer??? SQL> select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0;      STATE CR_SCN_BAS ---------- ----------          1          0          3    1227595 X$BH ??? STATE????Buffer???, ???????: STATE NUMBER KCBBHFREE 0 buffer free KCBBHEXLCUR 1 buffer current (and if DFS locked X) KCBBHSHRCUR 2 buffer current (and if DFS locked S) KCBBHCR 3 buffer consistant read KCBBHREADING 4 Being read KCBBHMRECOVERY 5 media recovery (current & special) KCBBHIRECOVERY 6 Instance recovery (somewhat special) ????????????? : state =1 Xcurrent ? state=2 Scurrent ? state=3 CR ??? Instance 2  ?? ????????????? ,???? gc current block 2 way  ??Current Block ??? Instance 2, ?? Instance 1 ??”Current Block” Convert ? Past Image: Instance 2 Session C SQL> update test set id=id+1 where id=2; 1 row updated. Instance 2 Session D SQL> select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0; STATE CR_SCN_BAS ---------- ---------- 1 0 3 1227641 3 1227638 STATE =1 ?Xcurrent block???? Instance 2 , ??? Instance 1 ??? GC??: Instance 1 Session B SQL> select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0;      STATE CR_SCN_BAS ---------- ----------          3    1227641          3    1227638          8          0          3    1227595 ???????, ??????Instance 1??session A????TEST??SELECT??? ,????? 3? State=3?CR ? ??????1?: Instance 1 session A ?????UPDATE? session SQL> alter session set events '10046 trace name context forever,level 8:10708 trace name context forever,level 103: trace[rac.*] disk high'; Session altered. SQL> select * from test;         ID ----------          2          2 select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0;       STATE CR_SCN_BAS ---------- ----------          3    1227716          3    1227713          8          0 ?????????v$BH ????CR????,?????SELECT??? CR????????,???????? ?????????? ??X$BH?????? , ?????CR??SCN Version???: 1227641?1227638?1227595, ?SELECT?????? 2???SCN version?CR? 1227716? 1227713 ???, Oracle????????? ?????????SELECT??????event 10708? rac.*???TRACE,??????TRACE??: PARSING IN CURSOR #140444679938584 len=337 dep=1 uid=0 oct=3 lid=0 tim=1335698913632292 hv=3345277572 ad='bc0e68c8' sqlid='baj7tjm3q9sn4' SELECT /* OPT_DYN_SAMP */ /*+ ALL_ROWS IGNORE_WHERE_CLAUSE NO_PARALLEL(SAMPLESUB) opt_param('parallel_execution_enabled', 'false') NO_PARALLEL_INDEX(SAMPLESUB) NO_SQL_TUNE */ NVL(SUM(C1),0), NVL(SUM(C2),0) FROM (SELECT /*+ NO_PARALLEL("TEST") FULL("TEST") NO_PARALLEL_INDEX("TEST") */ 1 AS C1, 1 AS C2 FROM "SYS"."TEST" "TEST") SAMPLESUB END OF STMT PARSE #140444679938584:c=1000,e=27630,p=0,cr=0,cu=0,mis=1,r=0,dep=1,og=1,plh=1950795681,tim=1335698913632252 EXEC #140444679938584:c=0,e=44,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=1,plh=1950795681,tim=1335698913632390 *** 2012-04-29 07:28:33.632 kclscrs: req=0 block=1/89233 *** 2012-04-29 07:28:33.632 kclscrs: bid=1:3:1:0:7:80:1:0:4:0:0:0:1:2:4:1:26:0:0:0:70:1a:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:4:3:2:1:2:0:3f:0:1c:86:2d:4:0:0:0:0:a2:3c:7c:b:70:1a:0:0:0:0:1:0:7a:f8:76:1d:1:2:dc:5:a9:fe:17:75:0:0:0:0:0:0:0:0:0:0:0:0:63:e5:0:0:0:0:0:0:10:0:0:0 2012-04-29 07:28:33.632578 : kjbcrc[0x15c91.1 76896.0][9] 2012-04-29 07:28:33.632616 : GSIPC:GMBQ: buff 0xba1e8f90, queue 0xbb79f278, pool 0x60013fa0, freeq 1, nxt 0xbb79f278, prv 0xbb79f278 2012-04-29 07:28:33.632634 : kjbmscrc(0x15c91.1)seq 0x2 reqid=0x1c(shadow 0xb4bb4458,reqid x1c)mas@2(infosz 200)(direct 1) 2012-04-29 07:28:33.632654 : kjbsentscn[0x0.12bbc1][to 2] 2012-04-29 07:28:33.632669 : GSIPC:SENDM: send msg 0xba1e9000 dest x20001 seq 24026 type 32 tkts xff0000 mlen x17001a0 2012-04-29 07:28:33.633385 : GSIPC:KSXPCB: msg 0xba1e9000 status 30, type 32, dest 2, rcvr 1 *** 2012-04-29 07:28:33.633 kclwcrs: wait=0 tm=689 *** 2012-04-29 07:28:33.633 kclwcrs: got 1 blocks from ksxprcv WAIT #140444679938584: nam='gc cr block 2-way' ela= 689 p1=1 p2=89233 p3=1 obj#=76896 tim=1335698913633418 2012-04-29 07:28:33.633490 : kjbcrcomplete[0x15c91.1 76896.0][0] 2012-04-29 07:28:33.633510 : kjbrcvdscn[0x0.12bbc1][from 2][idx 2012-04-29 07:28:33.633527 : kjbrcvdscn[no bscn <= rscn 0x0.12bbc1][from 2] *** 2012-04-29 07:28:33.633 kclwcrs: req=0 typ=cr(2) wtyp=2hop tm=689 ??TRACE???? ?????????TEST??????, ???????Dynamic Sampling?????,???????TEST?? CR???,???????’gc cr block 2-way’ ??: 2012-04-29 07:28:33.632654 : kjbsentscn[0x0.12bbc1][to 2] 12bbc1= 1227713  ???X$BH????CR???,kjbsentscn[0x0.12bbc1][to 2] ????? ? Instance 2 ???SCN=12bbc1=1227713   DBA=0x15c91.1 76896.0 ?  CR Request(obj#=76896) ??kjbrcvdscn????? [no bscn <= rscn 0x0.12bbc1][from 2] ,??? ??receive? SCN Version =12bbc1 ???Best Version CR Server Arch ??????????????????SELECT??: PARSING IN CURSOR #140444682869592 len=18 dep=0 uid=0 oct=3 lid=0 tim=1335698913635874 hv=1689401402 ad='b1a188f0' sqlid='c99yw1xkb4f1u' select * from test END OF STMT PARSE #140444682869592:c=4999,e=34017,p=0,cr=7,cu=0,mis=1,r=0,dep=0,og=1,plh=1357081020,tim=1335698913635870 EXEC #140444682869592:c=0,e=23,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=1,plh=1357081020,tim=1335698913635939 WAIT #140444682869592: nam='SQL*Net message to client' ela= 7 driver id=1650815232 #bytes=1 p3=0 obj#=0 tim=1335698913636071 *** 2012-04-29 07:28:33.636 kclscrs: req=0 block=1/89233 *** 2012-04-29 07:28:33.636 kclscrs: bid=1:3:1:0:7:83:1:0:4:0:0:0:1:2:4:1:26:0:0:0:70:1a:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:4:3:2:1:2:0:2:0:1c:86:2d:4:0:0:0:0:a2:3c:7c:b:70:1a:0:0:0:0:1:0:7d:f8:76:1d:1:2:dc:5:a9:fe:17:75:0:0:0:0:0:0:0:0:0:0:0:0:63:e5:0:0:0:0:0:0:10:0:0:0 2012-04-29 07:28:33.636209 : kjbcrc[0x15c91.1 76896.0][9] 2012-04-29 07:28:33.636228 : GSIPC:GMBQ: buff 0xba0e5d50, queue 0xbb79f278, pool 0x60013fa0, freeq 1, nxt 0xbb79f278, prv 0xbb79f278 2012-04-29 07:28:33.636244 : kjbmscrc(0x15c91.1)seq 0x3 reqid=0x1d(shadow 0xb4bb4458,reqid x1d)mas@2(infosz 200)(direct 1) 2012-04-29 07:28:33.636252 : kjbsentscn[0x0.12bbc4][to 2] 2012-04-29 07:28:33.636358 : GSIPC:SENDM: send msg 0xba0e5dc0 dest x20001 seq 24029 type 32 tkts xff0000 mlen x17001a0 2012-04-29 07:28:33.636861 : GSIPC:KSXPCB: msg 0xba0e5dc0 status 30, type 32, dest 2, rcvr 1 *** 2012-04-29 07:28:33.637 kclwcrs: wait=0 tm=865 *** 2012-04-29 07:28:33.637 kclwcrs: got 1 blocks from ksxprcv WAIT #140444682869592: nam='gc cr block 2-way' ela= 865 p1=1 p2=89233 p3=1 obj#=76896 tim=1335698913637294 2012-04-29 07:28:33.637356 : kjbcrcomplete[0x15c91.1 76896.0][0] 2012-04-29 07:28:33.637374 : kjbrcvdscn[0x0.12bbc4][from 2][idx 2012-04-29 07:28:33.637389 : kjbrcvdscn[no bscn <= rscn 0x0.12bbc4][from 2] *** 2012-04-29 07:28:33.637 kclwcrs: req=0 typ=cr(2) wtyp=2hop tm=865 ???, “SELECT * FROM TEST”??????’gc cr block 2-way’??:2012-04-29 07:28:33.637374 : kjbrcvdscn[0x0.12bbc4][from 2][idx 2012-04-29 07:28:33.637389 : kjbrcvdscn[no bscn ??Foreground Process? Remote LMS??got?? SCN=1227716 Version?CR, ??? ?????X$BH ?????scn??? ??????????Instance 1????2?SCN???CR?, ???????????Instance 1 Buffer Cache?? ??SCN Version ???CR ??????? ?????????: SQL> alter system set "_enable_minscn_cr"=false scope=spfile; System altered. SQL> alter system set "_db_block_max_cr_dba"=20 scope=spfile; System altered. SQL> startup force; ORA-32004: obsolete or deprecated parameter(s) specified for RDBMS instance ORACLE instance started. Total System Global Area 1570009088 bytes Fixed Size 2228704 bytes Variable Size 989859360 bytes Database Buffers 570425344 bytes Redo Buffers 7495680 bytes Database mounted. Database opened. ???? “_enable_minscn_cr”=false ? “_db_block_max_cr_dba”=20 ???RAC????, ??????: ?Instance 2 Session C ?update??????? ?????Instance 1 ????? ,????Instance 1?Request CR SQL> update test set id=id+1 where id=2; -- Instance 2 1 row updated. SQL> select * From test; -- Instance 1 ID ---------- 1 2 ??? Instance 1? X$BH?? select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0;  STATE CR_SCN_BAS ---------- ---------- 3 1273080 3 1273071 3 1273041 3 1273039 8 0 SQL> update test set id=id+1 where id=3; 1 row updated. SQL> select * From test; ID ---------- 1 2 SQL> select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0; STATE CR_SCN_BAS ---------- ---------- 3 1273091 3 1273080 3 1273071 3 1273041 3 1273039 8 0 ................... SQL> select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0; STATE CR_SCN_BAS ---------- ---------- 3 1273793 3 1273782 3 1273780 3 1273769 3 1273734 3 1273715 3 1273691 3 1273679 3 1273670 3 1273643 3 1273635 3 1273623 3 1273106 3 1273091 3 1273080 3 1273071 3 1273041 3 1273039 3 1273033 19 rows selected. SQL> select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0; STATE CR_SCN_BAS ---------- ---------- 3 1274993 ????? ???? “_enable_minscn_cr”(enable/disable minscn optimization for CR)=false ? “_db_block_max_cr_dba”=20 (Maximum Allowed Number of CR buffers per dba) 2? ??? ????? Instance 1 ??????????? ?? 19????CR?? “_enable_minscn_cr”?11g??????????,???Oracle????CR????SCN,?Foreground Process Receive????????????(SCN??)?SCN Version CR Block??????CBC?? SCN??????CR? , ?????????Buffer Cache??????? ????SCN Version?CR????,????? ?????????? ?????Snap_Scn ?? SCN?? ?????????Current SCN, ??????CR??????????????????????, ????Buffer Cache? ?????????? CR?????????, ?????? “_db_block_max_cr_dba” ???????, ???????????20 ,??????Buffer Cache?????19????CR?; ???”_db_block_max_cr_dba” ???????6 , ?????Buffer cache????????CR ???????6?? ??”_enable_minscn_cr” ??CR???MINSCN ??????, ?????????CR???????, ????? Foreground Process??????CR Request , ?? Holder Instance LMS ?build?? BEST CR ??, ?????????

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  • Working With Extended Events

    - by Fatherjack
    SQL Server 2012 has made working with Extended Events (XE) pretty simple when it comes to what sessions you have on your servers and what options you have selected and so forth but if you are like me then you still have some SQL Server instances that are 2008 or 2008 R2. For those servers there is no built-in way to view the Extended Event sessions in SSMS. I keep coming up against the same situations – Where are the xel log files? What events, actions or predicates are set for the events on the server? What sessions are there on the server already? I got tired of this being a perpetual question and wrote some TSQL to save as a snippet in SQL Prompt so that these details are permanently only a couple of clicks away. First, some history. If you just came here for the code skip down a few paragraphs and it’s all there. If you want a little time to reminisce about SQL Server then stick with me through the next paragraph or two. We are in a bit of a cross-over period currently, there are many versions of SQL Server but I would guess that SQL Server 2008, 2008 R2 and 2012 comprise the majority of installations. With each of these comes a set of management tools, of which SQL Server Management Studio (SSMS) is one. In 2008 and 2008 R2 Extended Events made their first appearance and there was no way to work with them in the SSMS interface. At some point the Extended Events guru Jonathan Kehayias (http://www.sqlskills.com/blogs/jonathan/) created the SQL Server 2008 Extended Events SSMS Addin which is really an excellent tool to ease XE session administration. This addin will install in SSMS 2008 or 2008R2 but not SSMS 2012. If you use a compatible version of SSMS then I wholly recommend downloading and using it to make your work with XE much easier. If you have SSMS 2012 installed, and there is no reason not to as it will let you work with all versions of SQL Server, then you cannot install this addin. If you are working with SQL Server 2012 then SSMS 2012 has built in functionality to manage XE sessions – this functionality does not apply for 2008 or 2008 R2 instances though. This means you are somewhat restricted and have to use TSQL to manage XE sessions on older versions of SQL Server. OK, those of you that skipped ahead for the code, you need to start from here: So, you are working with SSMS 2012 but have a SQL Server that is an earlier version that needs an XE session created or you think there is a session created but you aren’t sure, or you know it’s there but can’t remember if it is running and where the output is going. How do you find out? Well, none of the information is hidden as such but it is a bit of a wrangle to locate it and it isn’t a lot of code that is unlikely to remain in your memory. I have created two pieces of code. The first examines the SYS.Server_Event_… management views in combination with the SYS.DM_XE_… management views to give the name of all sessions that exist on the server, regardless of whether they are running or not and two pieces of TSQL code. One piece will alter the state of the session: if the session is running then the code will stop the session if executed and vice versa. The other piece of code will drop the selected session. If the session is running then the code will stop it first. Do not execute the DROP code unless you are sure you have the Create code to hand. It will be dropped from the server without a second chance to change your mind. /**************************************************************/ /***   To locate and describe event sessions on a server    ***/ /***                                                        ***/ /***   Generates TSQL to start/stop/drop sessions           ***/ /***                                                        ***/ /***        Jonathan Allen - @fatherjack                    ***/ /***                 June 2013                                ***/ /***                                                        ***/ /**************************************************************/ SELECT  [EES].[name] AS [Session Name - all sessions] ,         CASE WHEN [MXS].[name] IS NULL THEN ISNULL([MXS].[name], 'Stopped')              ELSE 'Running'         END AS SessionState ,         CASE WHEN [MXS].[name] IS NULL              THEN ISNULL([MXS].[name],                          'ALTER EVENT SESSION [' + [EES].[name]                          + '] ON SERVER STATE = START;')              ELSE 'ALTER EVENT SESSION [' + [EES].[name]                   + '] ON SERVER STATE = STOP;'         END AS ALTER_SessionState ,         CASE WHEN [MXS].[name] IS NULL              THEN ISNULL([MXS].[name],                          'DROP EVENT SESSION [' + [EES].[name]                          + '] ON SERVER; -- This WILL drop the session. It will no longer exist. Don't do it unless you are certain you can recreate it if you need it.')              ELSE 'ALTER EVENT SESSION [' + [EES].[name]                   + '] ON SERVER STATE = STOP; ' + CHAR(10)                   + '-- DROP EVENT SESSION [' + [EES].[name]                   + '] ON SERVER; -- This WILL stop and drop the session. It will no longer exist. Don't do it unless you are certain you can recreate it if you need it.'         END AS DROP_Session FROM    [sys].[server_event_sessions] AS EES         LEFT JOIN [sys].[dm_xe_sessions] AS MXS ON [EES].[name] = [MXS].[name] WHERE   [EES].[name] NOT IN ( 'system_health', 'AlwaysOn_health' ) ORDER BY SessionState GO I have excluded the system_health and AlwaysOn sessions as I don’t want to accidentally execute the drop script for these sessions that are created as part of the SQL Server installation. It is possible to recreate the sessions but that is a whole lot of aggravation I’d rather avoid. The second piece of code gathers details of running XE sessions only and provides information on the Events being collected, any predicates that are set on those events, the actions that are set to be collected, where the collected information is being logged and if that logging is to a file target, where that file is located. /**********************************************/ /***    Running Session summary                ***/ /***                                        ***/ /***    Details key values of XE sessions     ***/ /***    that are in a running state            ***/ /***                                        ***/ /***        Jonathan Allen - @fatherjack    ***/ /***        June 2013                        ***/ /***                                        ***/ /**********************************************/ SELECT  [EES].[name] AS [Session Name - running sessions] ,         [EESE].[name] AS [Event Name] ,         COALESCE([EESE].[predicate], 'unfiltered') AS [Event Predicate Filter(s)] ,         [EESA].[Action] AS [Event Action(s)] ,         [EEST].[Target] AS [Session Target(s)] ,         ISNULL([EESF].[value], 'No file target in use') AS [File_Target_UNC] -- select * FROM    [sys].[server_event_sessions] AS EES         INNER JOIN [sys].[dm_xe_sessions] AS MXS ON [EES].[name] = [MXS].[name]         INNER JOIN [sys].[server_event_session_events] AS [EESE] ON [EES].[event_session_id] = [EESE].[event_session_id]         LEFT JOIN [sys].[server_event_session_fields] AS EESF ON ( [EES].[event_session_id] = [EESF].[event_session_id]                                                               AND [EESF].[name] = 'filename'                                                               )         CROSS APPLY ( SELECT    STUFF(( SELECT  ', ' + sest.name                                         FROM    [sys].[server_event_session_targets]                                                 AS SEST                                         WHERE   [EES].[event_session_id] = [SEST].[event_session_id]                                       FOR                                         XML PATH('')                                       ), 1, 2, '') AS [Target]                     ) AS EEST         CROSS APPLY ( SELECT    STUFF(( SELECT  ', ' + [sesa].NAME                                         FROM    [sys].[server_event_session_actions]                                                 AS sesa                                         WHERE   [sesa].[event_session_id] = [EES].[event_session_id]                                       FOR                                         XML PATH('')                                       ), 1, 2, '') AS [Action]                     ) AS EESA WHERE   [EES].[name] NOT IN ( 'system_health', 'AlwaysOn_health' ) /*Optional to exclude 'out-of-the-box' traces*/ I hope that these scripts are useful to you and I would be obliged if you would keep my name in the script comments. I have no problem with you using it in production or personal circumstances, however it has no warranty or guarantee. Don’t use it unless you understand it and are happy with what it is going to do. I am not ever responsible for the consequences of executing this script on your servers.

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  • ?Oracle????SELECT????UNDO

    - by Liu Maclean(???)
    ????????Oracle?????(dirty read),?Oracle??????Asktom????????Oracle???????, ???undo??????????(before image)??????Consistent, ???????????????Oracle????????????? ????????? ??,??,Oracle?????????????RDBMS,???????????? ?????????2?????: _offline_rollback_segments or _corrupted_rollback_segments ?2?????????Oracle???????????ORA-600[4XXX]???????????????,???2??????Undo??Corruption????????????,?????2????????????????? ??????????????_offline_rollback_segments ? _corrupted_rollback_segments ?2?????: ???????(FORCE OPEN DATABASE) ????????????(consistent read & delayed block cleanout) ??????rollback segment??? ?????:???????Oracle????????,??????????2?????,?????????????!! _offline_rollback_segments ? _corrupted_rollback_segments ???????????: ??2???????Undo Segments(???/???)????????online ?UNDO$???????????OFFLINE??? ???instance??????????????????? ??????Undo Segments????????active transaction????????????dead??SMON???(????????SMON??(?):Recover Dead transaction) _OFFLINE_ROLLBACK_SEGMENTS(offline undo segment list)????(hidden parameter)?????: ???startup???open database???????_OFFLINE_ROLLBACK_SEGMENTS????Undo segments(???/???),?????undo segments????????alert.log???TRACE?????,???????startup?? ?????????????,?ITL?????undo segments?: ???undo segments?transaction table?????????????????? ???????????commit,?????CR??? ????undo segments????(???corrupted??,???missed??)???????????alert.log,??????? ?DML?????????????????????????????????CPU,????????????????????? _CORRUPTED_ROLLBACK_SEGMENTS(corrupted undo segment list)??????????: ?????startup?open database???_CORRUPTED_ROLLBACK_SEGMENTS????undo segments(???/???)???????? ???????_CORRUPTED_ROLLBACK_SEGMENTS???undo segments????????????commit,???undo segments???drop??? ??????????? ??????????????????,?????????????????? ??bootstrap???????????,?????????ORA-00704: bootstrap process failure??,???????????(???Oracle????:??ORA-00600:[4000] ORA-00704: bootstrap process failure????) ??????_CORRUPTED_ROLLBACK_SEGMENTS????????????????????,??????????????? Oracle???????TXChecker??????????? ???????2?????,??????????????_CORRUPTED_ROLLBACK_SEGMENTS?????SELECT????UNDO???????: SQL> alter system set event= '10513 trace name context forever, level 2' scope=spfile; System altered. SQL> alter system set "_in_memory_undo"=false scope=spfile; System altered. 10513 level 2 event????SMON ??rollback ??? dead transaction _in_memory_undo ?? in memory undo ?? SQL> startup force; ORACLE instance started. Total System Global Area 3140026368 bytes Fixed Size 2232472 bytes Variable Size 1795166056 bytes Database Buffers 1325400064 bytes Redo Buffers 17227776 bytes Database mounted. Database opened. session A: SQL> conn maclean/maclean Connected. SQL> create table maclean tablespace users as select 1 t1 from dual connect by level exec dbms_stats.gather_table_stats('','MACLEAN'); PL/SQL procedure successfully completed. SQL> set autotrace on; SQL> select sum(t1) from maclean; SUM(T1) ---------- 501 Execution Plan ---------------------------------------------------------- Plan hash value: 1679547536 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 1 | 3 | 3 (0)| 00:00:01 | | 1 | SORT AGGREGATE | | 1 | 3 | | | | 2 | TABLE ACCESS FULL| MACLEAN | 501 | 1503 | 3 (0)| 00:00:01 | ------------------------------------------------------------------------------ Statistics ---------------------------------------------------------- 1 recursive calls 0 db block gets 3 consistent gets 0 physical reads 0 redo size 515 bytes sent via SQL*Net to client 492 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processe ???????????,????current block, ????????,consistent gets??3? SQL> update maclean set t1=0; 501 rows updated. SQL> alter system checkpoint; System altered. ??session A?commit; ???? session: SQL> conn maclean/maclean Connected. SQL> SQL> set autotrace on; SQL> select sum(t1) from maclean; SUM(T1) ---------- 501 Execution Plan ---------------------------------------------------------- Plan hash value: 1679547536 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 1 | 3 | 3 (0)| 00:00:01 | | 1 | SORT AGGREGATE | | 1 | 3 | | | | 2 | TABLE ACCESS FULL| MACLEAN | 501 | 1503 | 3 (0)| 00:00:01 | ------------------------------------------------------------------------------ Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 505 consistent gets 0 physical reads 108 redo size 515 bytes sent via SQL*Net to client 492 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed ?????? ?????????undo??CR?,???consistent gets??? 505 [oracle@vrh8 ~]$ ps -ef|grep LOCAL=YES |grep -v grep oracle 5841 5839 0 09:17 ? 00:00:00 oracleG10R25 (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq))) [oracle@vrh8 ~]$ kill -9 5841 ??session A???Server Process????,???dead transaction ????smon?? select ktuxeusn, to_char(sysdate, 'DD-MON-YYYY HH24:MI:SS') "Time", ktuxesiz, ktuxesta from x$ktuxe where ktuxecfl = 'DEAD'; KTUXEUSN Time KTUXESIZ KTUXESTA ---------- -------------------- ---------- ---------------- 2 06-AUG-2012 09:20:45 7 ACTIVE ???1?active rollback segment SQL> conn maclean/maclean Connected. SQL> set autotrace on; SQL> select sum(t1) from maclean; SUM(T1) ---------- 501 Execution Plan ---------------------------------------------------------- Plan hash value: 1679547536 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 1 | 3 | 3 (0)| 00:00:01 | | 1 | SORT AGGREGATE | | 1 | 3 | | | | 2 | TABLE ACCESS FULL| MACLEAN | 501 | 1503 | 3 (0)| 00:00:01 | ------------------------------------------------------------------------------ Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 411 consistent gets 0 physical reads 108 redo size 515 bytes sent via SQL*Net to client 492 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed ????? ????kill?? ???smon ??dead transaction , ???????????? ?????undo??????? ????active?rollback segment??? SQL> select segment_name from dba_rollback_segs where segment_id=2; SEGMENT_NAME ------------------------------ _SYSSMU2$ SQL> alter system set "_corrupted_rollback_segments"='_SYSSMU2$' scope=spfile; System altered. ? _corrupted_rollback_segments ?? ???2?rollback segment, ????????undo SQL> startup force; ORACLE instance started. Total System Global Area 3140026368 bytes Fixed Size 2232472 bytes Variable Size 1795166056 bytes Database Buffers 1325400064 bytes Redo Buffers 17227776 bytes Database mounted. Database opened. SQL> conn maclean/maclean Connected. SQL> set autotrace on; SQL> select sum(t1) from maclean; SUM(T1) ---------- 94 Execution Plan ---------------------------------------------------------- Plan hash value: 1679547536 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 1 | 3 | 3 (0)| 00:00:01 | | 1 | SORT AGGREGATE | | 1 | 3 | | | | 2 | TABLE ACCESS FULL| MACLEAN | 501 | 1503 | 3 (0)| 00:00:01 | ------------------------------------------------------------------------------ Statistics ---------------------------------------------------------- 228 recursive calls 0 db block gets 29 consistent gets 5 physical reads 116 redo size 514 bytes sent via SQL*Net to client 492 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 4 sorts (memory) 0 sorts (disk) 1 rows processed SQL> / SUM(T1) ---------- 94 Execution Plan ---------------------------------------------------------- Plan hash value: 1679547536 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 1 | 3 | 3 (0)| 00:00:01 | | 1 | SORT AGGREGATE | | 1 | 3 | | | | 2 | TABLE ACCESS FULL| MACLEAN | 501 | 1503 | 3 (0)| 00:00:01 | ------------------------------------------------------------------------------ Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 3 consistent gets 0 physical reads 0 redo size 514 bytes sent via SQL*Net to client 492 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed ?????? consistent gets???3,?????????????????,??ITL???UNDO SEGMENTS?_corrupted_rollback_segments????,???????????COMMIT??,????UNDO? ???????,?????????????????????????(????????????????????),????????????????? ???? , ?????

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  • SQL SERVER – Auto Complete and Format T-SQL Code – Devart SQL Complete

    - by pinaldave
    Some people call it laziness, some will call it efficiency, some think it is the right thing to do. At any rate, tools are meant to make a job easier, and I like to use various tools. If we consider the history of the world, if we all wanted to keep traditional practices, we would have never invented the wheel.  But as time progressed, people wanted convenience and efficiency, which then led to laziness. Wanting a more efficient way to do something is not inherently lazy.  That’s how I see any efficiency tools. A few days ago I found Devart SQL Complete.  It took less than a minute to install, and after installation it just worked without needing any tweaking.  Once I started using it I was impressed with how fast it formats SQL code – you can write down any terms or even copy and paste.  You can start typing right away, and it will complete keywords, object names, and fragmentations. It completes statement expressions.  How many times do we write insert, update, delete?  Take this example: to alter a stored procedure name, we don’t remember the code written in it, you have to write it over again, or go back to SQL Server Studio Manager to create and alter which is very difficult.  With SQL Complete , you can write “alter stored procedure,” and it will finish it for you, and you can modify as needed. I love to write code, and I love well-written code.  When I am working with clients, and I find people whose code have not been written properly, I feel a little uncomfortable.  It is difficult to deal with code that is in the wrong case, with no line breaks, no white spaces, improper indents, and no text wrapping.  The worst thing to encounter is code that goes all the way to the right side, and you have to scroll a million times because there are no breaks or indents.  SQL Complete will take care of this for you – if a developer is too lazy for proper formatting, then Devart’s SQL formatter tool will make them better, not lazier. SQL Management Studio gives information about your code when you hover your mouse over it, however SQL Complete goes further in it, going into the work table, and the current rate idea, too. It gives you more information about the parameters; and last but not least, it will just take you to the help file of code navigation.  It will open object explorer in a document viewer.  You can start going through the various properties of your code – a very important thing to do. Here are are interesting Intellisense examples: 1) We are often very lazy to expand *however, when we are using SQL Complete we can just mouse over the * and it will give us all the the column names and we can select the appropriate columns. 2) We can put the cursor after * and it will give us option to expand it to all the column names by pressing the Tab key. 3) Here is one more Intellisense feature I really liked it. I always alias my tables and I always select the alias with special logic. When I was using SQL Complete I selected just a tablename (without schema name) and…(just like below image) … and it autocompleted the schema and alias name (the way I needed it). I believe using SQL Complete we can work faster.  It supports all versions of SQL Server, and works SQL formatting.  Many businesses perform code review and have code standards, so why not use an efficiency tool on everyone’s computer and make sure the code is written correctly from the first time?  If you’re interested in this tool, there are free editions available.  If you like it, you can buy it.  I bought it because it works.  I love it, and I want to hear all your opinions on it, too. You can get the product for FREE.  Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Utility, T SQL, Technology

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  • Migrating SQL Server Databases – The DBA’s Checklist (Part 3)

    - by Sadequl Hussain
    Continuing from Part 2 of the Database Migration Checklist series: Step 10: Full-text catalogs and full-text indexing This is one area of SQL Server where people do not seem to take notice unless something goes wrong. Full-text functionality is a specialised area in database application development and is not usually implemented in your everyday OLTP systems. Nevertheless, if you are migrating a database that uses full-text indexing on one or more tables, you need to be aware a few points. First of all, SQL Server 2005 now allows full-text catalog files to be restored or attached along with the rest of the database. However, after migration, if you are unable to look at the properties of any full-text catalogs, you are probably better off dropping and recreating it. You may also get the following error messages along the way: Msg 9954, Level 16, State 2, Line 1 The Full-Text Service (msftesql) is disabled. The system administrator must enable this service. This basically means full text service is not running (disabled or stopped) in the destination instance. You will need to start it from the Configuration Manager. Similarly, if you get the following message, you will also need to drop and recreate the catalog and populate it. Msg 7624, Level 16, State 1, Line 1 Full-text catalog ‘catalog_name‘ is in an unusable state. Drop and re-create this full-text catalog. A full population of full-text indexes can be a time and resource intensive operation. Obviously you will want to schedule it for low usage hours if the database is restored in an existing production server. Also, bear in mind that any scheduled job that existed in the source server for populating the full text catalog (e.g. nightly process for incremental update) will need to be re-created in the destination. Step 11: Database collation considerations Another sticky area to consider during a migration is the collation setting. Ideally you would want to restore or attach the database in a SQL Server instance with the same collation. Although not used commonly, SQL Server allows you to change a database’s collation by using the ALTER DATABASE command: ALTER DATABASE database_name COLLATE collation_name You should not be using this command for no reason as it can get really dangerous.  When you change the database collation, it does not change the collation of the existing user table columns.  However the columns of every new table, every new UDT and subsequently created variables or parameters in code will use the new setting. The collation of every char, nchar, varchar, nvarchar, text or ntext field of the system tables will also be changed. Stored procedure and function parameters will be changed to the new collation and finally, every character-based system data type and user defined data types will also be affected. And the change may not be successful either if there are dependent objects involved. You may get one or multiple messages like the following: Cannot ALTER ‘object_name‘ because it is being referenced by object ‘dependent_object_name‘. That is why it is important to test and check for collation related issues. Collation also affects queries that use comparisons of character-based data.  If errors arise due to two sides of a comparison being in different collation orders, the COLLATE keyword can be used to cast one side to the same collation as the other. Continues…

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  • How to reclaim storage for deleted LOBs

    - by Jim Hudson
    I have a LOB tablespace. Currently holding 9GB out of 12GB available. And, as far as I can tell, deleting records doesn't reclaim any storage in the tablespace. I'm getting worried about handling further processing. This is Oracle 11.1 and the data are in a CLOB and a BLOB column in the same table. The LOB Index segments (SYS_IL...) are small, all the storage is in the data segments (SYS_LOB...) We'e tried purge and coalesce and didn't get anywhere -- same number of bytes in user_extents. "Alter table xxx move" will work, but we'd need to have someplace to move it to that has enough space for the revised data. We'd also need to do that off hours and rebuild the indexes, of course, but that's easy enough. Copying out the good data and doing a truncate, then copying it back, will also work. But that's pretty much just what the "alter table" command does. Am I missing some easy ways to shrink things down and get the storage back? Or is "alter table xxx move" the best approach? Or is this a non-issue and Oracle will grab back the space from the deleted lob rows when it needs it?

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  • "If not exists" fails on SQL CE

    - by Mark Evans
    Hi I've got an unexpected problem. I'm making a script to update the schema on a SQL CE database. This won't run: if not exists ( Select column_name from information_schema.columns where column_name = 'TempTestField' and table_name = 'Inventory_Master_File' ) Alter table Inventory_Master_File add TempTestField nvarchar(10) null I think this is because I'm using stuff that isn't supported in SQL CE. Anyone know how to do this? I've tried rearranging the script and can't get anything to work. I tried "alter table ... where not exists ...". Note that the "select" part runs fine and also the "alter" part. The problem is "if not exists". I know there are some other postings regarding problems like this using SQL CE but I couldn't find an answer to this particular problem. Cheers Mark UPDATE: I've spent over an hour looking for a solution. I've found many postings asking for help with similar problems but I've still got no idea how to fix it. I really don't want to do this in C# code. I need to do this in a SQL script. I can't believe something this basic is causing so much difficulty :(

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  • Synchronizing an ERWin model with a Visual Studio 2008 GDR 2/2010 db project

    - by Grant Back
    I am looking for options to get our vast collection of DB objects across many DBs into source control (TFS 2010). Once we succeed here, we will work toward generating our alter scripts for a particular DB change via TFS build. The problem is, our data architecture group is responsible for maintaining the DB objects (excluding SPs), and they work within a model centric process, via ERWin. What this means, is that they maintain the DBs via ERWin models, and generate alters from them that are used to release changes. In order to achieve our goal of getting the DB objects (not just the ERWin models) into TFS, I believe the best option is to do this via Visual Studio DB projects. From what I can tell, there is very little urgency for CA to continue supporting an integration between ERWin and Visual Studio, that no longer works as of Visual Studio 2008 DB Ed. GDR. If I have been mislead in this regard, please feel free to set me straight. One potential solution is to: Perform changes in the ERWin model. Take the alter script generated from ERWin, and import the script into the appropriate Visual Studio DB project, updating the objects in the in the DB project Check the changed objects in the DB project into TFS. TFS Build executes to generate the alter scripts that will be used to push the changes through our release process. My question is, is this solution viable, or are there any other options?

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  • The type of field isn't supported by declared persistence strategy "OneToMany"

    - by Robert
    We are new to JPA and trying to setup a very simple one to many relationship where a pojo called Message can have a list of integer group id's defined by a join table called GROUP_ASSOC. Here is the DDL: CREATE TABLE "APP"."MESSAGE" ( "MESSAGE_ID" INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1) ); ALTER TABLE "APP"."MESSAGE" ADD CONSTRAINT "MESSAGE_PK" PRIMARY KEY ("MESSAGE_ID"); CREATE TABLE "APP"."GROUP_ASSOC" ( "GROUP_ID" INTEGER NOT NULL, "MESSAGE_ID" INTEGER NOT NULL ); ALTER TABLE "APP"."GROUP_ASSOC" ADD CONSTRAINT "GROUP_ASSOC_PK" PRIMARY KEY ("MESSAGE_ID", "GROUP_ID"); ALTER TABLE "APP"."GROUP_ASSOC" ADD CONSTRAINT "GROUP_ASSOC_FK" FOREIGN KEY ("MESSAGE_ID") REFERENCES "APP"."MESSAGE" ("MESSAGE_ID"); Here is the pojo: @Entity @Table(name = "MESSAGE") public class Message { @Id @Column(name = "MESSAGE_ID") @GeneratedValue(strategy = GenerationType.IDENTITY) private int messageId; @OneToMany(fetch=FetchType.LAZY, cascade=CascadeType.PERSIST) private List groupIds; public int getMessageId() { return messageId; } public void setMessageId(int messageId) { this.messageId = messageId; } public List getGroupIds() { return groupIds; } public void setGroupIds(List groupIds) { this.groupIds = groupIds; } } When we try to execute the following test code we get <openjpa-1.2.3-SNAPSHOT-r422266:907835 fatal user error> org.apache.openjpa.util.MetaDataException: The type of field "pojo.Message.groupIds" isn't supported by declared persistence strategy "OneToMany". Please choose a different strategy. Message msg = new Message(); List groups = new ArrayList(); groups.add(101); groups.add(102); EntityManager em = Persistence.createEntityManagerFactory("TestDBWeb").createEntityManager(); em.getTransaction().begin(); em.persist(msg); em.getTransaction().commit(); Help!

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  • Updating a Foreign Key constraint with ON DELETE CASCADE not updating?

    - by Alastair Pitts
    We've realised in our SQL Server 2005 DB that some Foreign Keys don't have the On Delete Cascade property set, which is giving us a couple of referential errors when we try and delete some records. Use the Management Studio I scripted the DROP and CREATESQL's, but it seems that the CREATE isn't working correctly. The DROP: USE [FootprintReports] GO IF EXISTS (SELECT * FROM sys.foreign_keys WHERE object_id = OBJECT_ID(N'[dbo].[FK__SUBSCRIPTIONS_Reports]') AND parent_object_id = OBJECT_ID(N'[dbo].[_SUBSCRIPTIONS]')) ALTER TABLE [dbo].[_SUBSCRIPTIONS] DROP CONSTRAINT [FK__SUBSCRIPTIONS_Reports] and the CREATE USE [FootprintReports] GO ALTER TABLE [dbo].[_SUBSCRIPTIONS] WITH CHECK ADD CONSTRAINT [FK__SUBSCRIPTIONS_Reports] FOREIGN KEY([PARAMETER_ReportID]) REFERENCES [dbo].[Reports] ([ID]) ON DELETE CASCADE GO ALTER TABLE [dbo].[_SUBSCRIPTIONS] CHECK CONSTRAINT [FK__SUBSCRIPTIONS_Reports] If I manually change the value of the On Delete in the GUI, after dropping and recreating, the On Delete isn't correctly updated. As a test, I set the Delete rule in the GUI to Set Null. It dropped correctly, and recreated without error. If I got back into the GUI, it is still showing the Set Null as the Delete Rule. Have I done something wrong? or is there another way to edit a constraint to add the ON DELETE CASCADE rule?

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  • Updating nullability of columns in SQL 2008

    - by Shaul
    I have a very wide table, containing lots and lots of bit fields. These bit fields were originally set up as nullable. Now we've just made a decision that it doesn't make sense to have them nullable; the value is either Yes or No, default No. In other words, the schema should change from: create table MyTable( ID bigint not null, Name varchar(100) not null, BitField1 bit null, BitField2 bit null, ... BitFieldN bit null ) to create table MyTable( ID bigint not null, Name varchar(100) not null, BitField1 bit not null, BitField2 bit not null, ... BitFieldN bit not null ) alter table MyTable add constraint DF_BitField1 default 0 for BitField1 alter table MyTable add constraint DF_BitField2 default 0 for BitField2 alter table MyTable add constraint DF_BitField3 default 0 for BitField3 So I've just gone in through the SQL Management Studio, updating all these fields to non-nullable, default value 0. And guess what - when I try to update it, SQL Mgmt studio internally recreates the table and then tries to reinsert all the data into the new table... including the null values! Which of course generates an error, because it's explicitly trying to insert a null value into a non-nullable column. Aaargh! Obviously I could run N update statements of the form: update MyTable set BitField1 = 0 where BitField1 is null update MyTable set BitField2 = 0 where BitField2 is null but as I said before, there are n fields out there, and what's more, this change has to propagate out to several identical databases. Very painful to implement manually. Is there any way to make the table modification just ignore the null values and allow the default rule to kick in when you attempt to insert a null value?

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  • How to disable mod_security2 rule (false positive) for one domain on centos 5

    - by nicholas.alipaz
    Hi I have mod_security enabled on a centos5 server and one of the rules is keeping a user from posting some text on a form. The text is legitimate but it has the words 'create' and an html <table> tag later in it so it is causing a false positive. The error I am receiving is below: [Sun Apr 25 20:36:53 2010] [error] [client 76.171.171.xxx] ModSecurity: Access denied with code 500 (phase 2). Pattern match "((alter|create|drop)[[:space:]]+(column|database|procedure|table)|delete[[:space:]]+from|update.+set.+=)" at ARGS:body. [file "/usr/local/apache/conf/modsec2.user.conf"] [line "352"] [id "300015"] [rev "1"] [msg "Generic SQL injection protection"] [severity "CRITICAL"] [hostname "www.mysite.com"] [uri "/node/181/edit"] [unique_id "@TaVDEWnlusAABQv9@oAAAAD"] and here is /usr/local/apache/conf/modsec2.user.conf (line 352) #Generic SQL sigs SecRule ARGS "((alter|create|drop)[[:space:]]+(column|database|procedure|table)|delete[[:space:]]+from|update.+set.+=)" "id:1,rev:1,severity:2,msg:'Generic SQL injection protection'" The questions I have are: What should I do to "whitelist" or allow this rule to get through? What file do I create and where? How should I alter this rule? Can I set it to only be allowed for the one domain, since it is the only one having the issue on this dedicated server or is there a better way to exclude table tags perhaps? Thanks guys

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  • symfony doctrine build-sql error

    - by user313571
    I have some big problems with symfony and doctrine at the beginning of a new project. I have created database diagram with mysql workbench, inserted the sql into phpmyadmin and then I've tried symfony doctrine:build-schema to generate the YAML schema. It generates a wrong schema (relations don't have on delete/on update) and after this I've tried symfony doctrine:build --sql and symfony doctrine:insert-sql The insert-sql statement generates error (can't create table ... failing query alter table add constraint ....), so I've decided to take a look over the generated sql and I've found out some differences between the sql generated from mysql workbench (which works perfect, including relations) and the sql generated by doctrine. I'll be short from now: I have to tables, EVENT and FORM and a 1 to n relation (each event may have multiple forms) so the correct constraint (generated with workbench) is ALTER TABLE `form` ADD CONSTRAINT `fk_form_event1` FOREIGN KEY (`event_id`) REFERENCES `event` (`id`) ON DELETE CASCADE ON UPDATE CASCADE; doctrine generated statement is: ALTER TABLE event ADD CONSTRAINT event_id_form_event_id FOREIGN KEY (id) REFERENCES form(event_id); It's totally reversed and I am sure here is the error. What should I do? It's also correct like this?

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  • how to use a parameterized function for the Default Binding of a Sql Server column

    - by Walt Gaber
    I have a table that catalogs selected files from multiple sources. I want to record whether a file is a duplicate of a previously cataloged file at the time the new file is cataloged. I have a column in my table (“primary_duplicate”) to record each entry as ‘P’ (primary) or ‘D’ (duplicate). I would like to provide a Default Binding for this column that would check for other occurrences of this file (i.e. name, length, timestamp) at the time the new file is being recorded. I have created a function that performs this check (see “GetPrimaryDuplicate” below). But I don’t know how to bind this function which requires three parameters to the table’s “primary_duplicate” column as its Default Binding. I would like to avoid using a trigger. I currently have a stored procedure used to insert new records that performs this check. But I would like to ensure that the flag is set correctly if an insert is performed outside of this stored procedure. How can I call this function with values from the row that is being inserted? USE [MyDatabase] GO SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo].[FileCatalog]( [id] [uniqueidentifier] NOT NULL, [catalog_timestamp] [datetime] NOT NULL, [primary_duplicate] nchar NOT NULL, [name] nvarchar NULL, [length] [bigint] NULL, [timestamp] [datetime] NULL ) ON [PRIMARY] GO ALTER TABLE [dbo].[FileCatalog] ADD CONSTRAINT [DF_FileCatalog_id] DEFAULT (newid()) FOR [id] GO ALTER TABLE [dbo].[FileCatalog] ADD CONSTRAINT [DF_FileCatalog_catalog_timestamp] DEFAULT (getdate()) FOR [catalog_timestamp] GO ALTER TABLE [dbo].[FileCatalog] ADD CONSTRAINT [DF_FileCatalog_primary_duplicate] DEFAULT (N'GetPrimaryDuplicate(name, length, timestamp)') FOR [primary_duplicate] GO USE [MyDatabase] GO SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE FUNCTION [dbo].[GetPrimaryDuplicate] ( @name nvarchar(255), @length bigint, @timestamp datetime ) RETURNS nchar(1) AS BEGIN DECLARE @c int SELECT @c = COUNT(*) FROM FileCatalog WHERE name=@name and length=@length and timestamp=@timestamp and primary_duplicate = 'P' IF @c > 0 RETURN 'D' -- Duplicate RETURN 'P' -- Primary END GO

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  • Problem updating values in combobox in vb.net

    - by user225269
    I have this code, but I have a problem. When I update but do not really made any changes to the value and press the update button, the data becomes null. And it will seem that I deleted the value. I've taught of a solution, that is to add both combobox1.selectedtext and combobox1.selecteditem to the function. But it doesn't work. combobox1.selecteditem is working when you try to alter the values when you update. But will save a null value when you don't alter the values using the combobox combobox1.selectedtext will save the data into the database even without altering. But will not save the data if you try to alter it. -And I incorporated both of them, but still only one is performing, and I think it is the one that I added first: Dim shikai As New Updater Try shikai.id = TextBox1.Text shikai.fname = TextBox2.Text shikai.mi = TextBox3.Text shikai.lname = TextBox4.Text shikai.ad = TextBox5.Text shikai.contact = TextBox9.Text shikai.year = ComboBox1.SelectedText shikai.section = ComboBox2.SelectedText shikai.gender = ComboBox3.SelectedText shikai.religion = ComboBox4.SelectedText shikai.year = ComboBox1.SelectedItem shikai.section = ComboBox2.SelectedItem shikai.gender = ComboBox3.SelectedItem shikai.religion = ComboBox4.SelectedItem shikai.bday = TextBox6.Text shikai.updates() MsgBox("Successfully updated!") Please help, what would be a simple workaround to solve this problem?

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  • Problems using dual resolver

    - by user315228
    Hi, I ma using dual resolver and having a problem. Following is what i get when i run through ant in debug and verbose mode([http://repo1.maven.org/maven2/axis2/axis2/working@commons-lang/[email protected]]) [ivy:retrieve] resolved ivy file produced in c:\temp\ivy\[email protected] [ivy:retrieve] :: downloading artifacts :: [ivy:retrieve] [NOT REQUIRED] config#ego;4.3.1!ego.conf [ivy:retrieve] trying [http://repo1.maven.org/maven2/axis2/axis2/working@commons-lang/[email protected]] [ivy:retrieve] tried [http://repo1.maven.org/maven2/axis2/axis2/working@commons-lang/[email protected]] [ivy:retrieve] HTTP response status: 404 url=[http://repo1.maven.org/maven2/axis2/axis2/working@commons-lang/[email protected]] [ivy:retrieve] CLIENT ERROR: Not Found url=[http://repo1.maven.org/maven2/axis2/axis2/working@commons-lang/[email protected]] [ivy:retrieve] ibiblio: resource not reachable for axis2#axis2;working@commons-lang: res=[http://repo1.maven.org/maven2/axis2/axis2/working@commons-lang/[email protected]] [ivy:retrieve] WARN: [NOT FOUND ] axis2#axis2;working@commons-lang!axis2.jar (235ms) [ivy:retrieve] WARN: ==== commons-lang: tried [ivy:retrieve] WARN: ==== ibiblio: tried [ivy:retrieve] WARN: [http://repo1.maven.org/maven2/axis2/axis2/working@commons-lang/[email protected]] [ivy:retrieve] [NOT REQUIRED] axis#axis-saaj;1.4!axis-saaj.jar [ivy:retrieve] [NOT REQUIRED] axis#axis-wsdl4j;1.5.1!axis-wsdl4j.jar Can you please tell me what is wrong with my ivysetting file or wrong with ivy file? Following is excerpt from ivysettings.xml <dual name="dual4" <filesystem name="commons-lang" <ivy pattern="${localRepositoryLocation}/[module]/ivy/ivy.xml"/ </filesystem <ibiblio name="ibiblio" m2compatible="true" usepoms="false" / </dual The problem (may be) is for each and every dependancy that i defined i have seperate ivy.xml. and just one reolver as above? like just for an exampe, for axis2.jar i have two dependancies in another ivy.xml, the dependencies are axis-saaj and axis-wsdl4j. Please help Thanks, Almas

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  • RFC 1918 address on open internet?

    - by longneck
    In trying to diagnose a failover problem with my Cisco ASA 5520 firewalls, I ran a traceroute to www.btfl.com and, much to my surprise, some of the hops came back as RFC 1918 addresses. Just to be clear, this host is not behind my firewall and there is no VPN involved. I have to connect across the open internet to get there. How/why is this possible? asa# traceroute www.btfl.com Tracing the route to 157.56.176.94 1 <redacted> 2 <redacted> 3 <redacted> 4 <redacted> 5 nap-edge-04.inet.qwest.net (67.14.29.170) 0 msec 10 msec 10 msec 6 65.122.166.30 0 msec 0 msec 10 msec 7 207.46.34.23 10 msec 0 msec 10 msec 8 * * * 9 207.46.37.235 30 msec 30 msec 50 msec 10 10.22.112.221 30 msec 10.22.112.219 30 msec 10.22.112.223 30 msec 11 10.175.9.193 30 msec 30 msec 10.175.9.67 30 msec 12 100.94.68.79 40 msec 100.94.70.79 30 msec 100.94.71.73 30 msec 13 100.94.80.39 30 msec 100.94.80.205 40 msec 100.94.80.137 40 msec 14 10.215.80.2 30 msec 10.215.68.16 30 msec 10.175.244.2 30 msec 15 * * * 16 * * * 17 * * * and it does the same thing from my FiOS connection at home: C:\>tracert www.btfl.com Tracing route to www.btfl.com [157.56.176.94] over a maximum of 30 hops: 1 1 ms <1 ms <1 ms myrouter.home [192.168.1.1] 2 8 ms 7 ms 8 ms <redacted> 3 10 ms 13 ms 11 ms <redacted> 4 12 ms 10 ms 10 ms ae2-0.TPA01-BB-RTR2.verizon-gni.net [130.81.199.82] 5 16 ms 16 ms 15 ms 0.ae4.XL2.MIA19.ALTER.NET [152.63.8.117] 6 14 ms 16 ms 16 ms 0.xe-11-0-0.GW1.MIA19.ALTER.NET [152.63.85.94] 7 19 ms 16 ms 16 ms microsoft-gw.customer.alter.net [63.65.188.170] 8 27 ms 33 ms * ge-5-3-0-0.ash-64cb-1a.ntwk.msn.net [207.46.46.177] 9 * * * Request timed out. 10 44 ms 43 ms 43 ms 207.46.37.235 11 42 ms 41 ms 40 ms 10.22.112.225 12 42 ms 43 ms 43 ms 10.175.9.1 13 42 ms 41 ms 42 ms 100.94.68.79 14 40 ms 40 ms 41 ms 100.94.80.193 15 * * * Request timed out.

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  • How to create a database in Oracle8 Lite with Developer 2000 ?

    - by Tareq
    Hi all, I am new in Oracle. I install Oracle 8 Lite with Developer 2000. Now I want to create a database for me. For that I open Oracle8 Navigator and Create a database which user is system. But in Oracle SQL*Plus I can not communicate with the database. Or even after creating a table using Oracle8 Navigator I can't alter the table. Please tell me how can I alter my table?

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  • Sql Server 2008 Create Foreign Key Manually

    - by tgriffiths
    I have inherited an old database which wasn't designed very well. It is a Sql Server 2008 database which is missing quite a lot of Foreign Key relationships. Below shows two of the tables, and I am trying to manually create a FK relationship between dbo.app_status.status_id and dbo.app_additional_info.application_id I am using SQL Server Management Studio when trying to create the relationship using the query below USE myDatabase; GO ALTER TABLE dbo.app_additional_info ADD CONSTRAINT FK_AddInfo_AppStatus FOREIGN KEY (application_id) REFERENCES dbo.app_status (status_id) ON DELETE CASCADE ON UPDATE CASCADE ; GO However, I receive this error when I run the query The ALTER TABLE statement conflicted with the FOREIGN KEY constraint "FK_AddInfo_AppStatus". The conflict occurred in database "myDatabase", table "dbo.app_status", column 'status_id'. I am wondering if the query is failing because each table already contains approximately 130,000 records? Please help. Thanks.

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  • Dropping duplicate|redundant Unique Constraint from FILESTREAM table

    - by electricsk8
    I have a table with a FILESTREAM column, and it has two unique constraints specified for the same FILESTREAM column, ie: ALTER TABLE [dbo].[TableName] ADD CONSTRAINT [UQ_TableName_33C4988760FC61CA] UNIQUE NONCLUSTERED ([GUID_Column]); GO ALTER TABLE [dbo].[TableName] ADD CONSTRAINT [UQ_TableName_33C49887145C0A3F] UNIQUE NONCLUSTERED ([GUID_Column]); GO I'd like to drop one of the unique constraints, as they are duplicates. However, when I try and drop one of the two duplicate constraints, I receive the following error. "A table with FILESTREAM column(s) must have a non-NULL unique ROWGUID column." Anyone know how to remove one of the two constraints?

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  • MySQL: how to convert many MyISAM tables to InnoDB in a production database?

    - by Continuation
    We have a production database that is made up entirely of MyISAM tables. We are considering converting them to InnoDB to gain better concurrency & reliability. Can I just alter the myISAM tables to InnoDB without shutting down MySQL? What are the recommend procedures here? How long will such a conversion take? All the tables have a total size of about 700MB There are quite a large number of tables. Is there any way to apply ALTER TABLE to all the MyISAM tables at once instead of doing it one by one? Any pitfalls I need to be aware of? Thank you

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  • Problem creating a database with PHP PDO

    - by Leandro Alonso
    Hello guys, I'm having a problem with a SQL query in my PHP Application. When the user access it for the first time, the app executes this query to create all the database: CREATE TABLE `databases` ( `id` bigint(20) NOT NULL auto_increment, `driver` varchar(45) NOT NULL, `server` text NOT NULL, `user` text NOT NULL, `password` text NOT NULL, `database` varchar(200) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ; -- -------------------------------------------------------- -- -- Table structure for table `modules` -- CREATE TABLE `modules` ( `id` bigint(20) unsigned NOT NULL auto_increment, `title` varchar(100) NOT NULL, `type` varchar(150) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=29 ; -- -------------------------------------------------------- -- -- Table structure for table `modules_data` -- CREATE TABLE `modules_data` ( `id` bigint(20) NOT NULL auto_increment, `module_id` bigint(20) unsigned NOT NULL, `key` varchar(150) NOT NULL, `value` tinytext, PRIMARY KEY (`id`), KEY `fk_modules_data_modules` (`module_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=184 ; -- -------------------------------------------------------- -- -- Table structure for table `modules_position` -- CREATE TABLE `modules_position` ( `user_id` bigint(20) unsigned NOT NULL, `tab_id` bigint(20) unsigned NOT NULL, `module_id` bigint(20) unsigned NOT NULL, `column` smallint(1) default NULL, `line` smallint(1) default NULL, PRIMARY KEY (`user_id`,`tab_id`,`module_id`), KEY `fk_modules_order_users` (`user_id`), KEY `fk_modules_order_tabs` (`tab_id`), KEY `fk_modules_order_modules` (`module_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; -- -------------------------------------------------------- -- -- Table structure for table `tabs` -- CREATE TABLE `tabs` ( `id` bigint(20) unsigned NOT NULL auto_increment, `title` varchar(60) NOT NULL, `columns` smallint(1) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=12 ; -- -------------------------------------------------------- -- -- Table structure for table `tabs_has_modules` -- CREATE TABLE `tabs_has_modules` ( `tab_id` bigint(20) unsigned NOT NULL, `module_id` bigint(20) unsigned NOT NULL, PRIMARY KEY (`tab_id`,`module_id`), KEY `fk_tabs_has_modules_tabs` (`tab_id`), KEY `fk_tabs_has_modules_modules` (`module_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; -- -------------------------------------------------------- -- -- Table structure for table `users` -- CREATE TABLE `users` ( `id` bigint(20) unsigned NOT NULL auto_increment, `login` varchar(60) NOT NULL, `password` varchar(64) NOT NULL, `email` varchar(100) NOT NULL, `name` varchar(250) default NULL, `user_level` bigint(20) unsigned NOT NULL, PRIMARY KEY (`id`), KEY `fk_users_user_levels` (`user_level`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ; -- -------------------------------------------------------- -- -- Table structure for table `users_has_tabs` -- CREATE TABLE `users_has_tabs` ( `user_id` bigint(20) unsigned NOT NULL, `tab_id` bigint(20) unsigned NOT NULL, `order` smallint(2) NOT NULL, `columns_width` varchar(255) default NULL, PRIMARY KEY (`user_id`,`tab_id`), KEY `fk_users_has_tabs_users` (`user_id`), KEY `fk_users_has_tabs_tabs` (`tab_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; -- -------------------------------------------------------- -- -- Table structure for table `user_levels` -- CREATE TABLE `user_levels` ( `id` bigint(20) unsigned NOT NULL auto_increment, `level` smallint(2) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ; -- -------------------------------------------------------- -- -- Table structure for table `user_meta` -- CREATE TABLE `user_meta` ( `id` bigint(20) unsigned NOT NULL auto_increment, `user_id` bigint(20) unsigned default NULL, `key` varchar(150) NOT NULL, `value` longtext NOT NULL, PRIMARY KEY (`id`), KEY `fk_user_meta_users` (`user_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ; -- -- Constraints for dumped tables -- -- -- Constraints for table `modules_data` -- ALTER TABLE `modules_data` ADD CONSTRAINT `fk_modules_data_modules` FOREIGN KEY (`module_id`) REFERENCES `modules` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION; -- -- Constraints for table `modules_position` -- ALTER TABLE `modules_position` ADD CONSTRAINT `fk_modules_order_modules` FOREIGN KEY (`module_id`) REFERENCES `modules` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION, ADD CONSTRAINT `fk_modules_order_tabs` FOREIGN KEY (`tab_id`) REFERENCES `tabs` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION, ADD CONSTRAINT `fk_modules_order_users` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION; -- -- Constraints for table `users` -- ALTER TABLE `users` ADD CONSTRAINT `fk_users_user_levels` FOREIGN KEY (`user_level`) REFERENCES `user_levels` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION; -- -- Constraints for table `user_meta` -- ALTER TABLE `user_meta` ADD CONSTRAINT `fk_user_meta_users` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION; INSERT INTO `user_levels` VALUES(1, 10); INSERT INTO `user_levels` VALUES(2, 1); INSERT INTO `users` VALUES(1, 'admin', 'password', '[email protected]', NULL, 1); INSERT INTO `user_meta` VALUES (NULL, 1, 'last_tab', 1); In some environments i get this error: SQLSTATE[HY000]: General error: 1005 Can't create table 'dms.databases' (errno: 150) I tried everything that I could find on Google but nothing works. The strange part is that if I run this query in PhpMyAdmin he creates my database, without any error.

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  • Who benefits from the use of Design Patterns?

    Who benefits from the use of design patterns is like asking who benefits from clean air or a good education. All of the stakeholders of a project benefit from the use of design patterns. Project Sponsor Project sponsors benefit from the use of design patterns because they promote reduced development time which translates in to shorter project timelines and greater return on investment compared to other projects that do not make use of design patterns. Project Manager Project managers benefit from the use of design patterns because they reduce the amount of time needed to design a system, and typically the sub components of the system already have a proven track record. System Architect/Engineer System architects/engineers benefit from the use of design patterns because reduce the amount of time needed to design the core a system. The additional time is used to alter the design pattern through the use of innovative design and common design principles to adhere to the project’s requirements. Programmer Programmers benefit from the use of design patterns because they can reuse existing code already established by the design pattern and only have to integrate the changes outlined by the system architects/engineers. Tester Testers benefit from the use of design patterns because they can alter the existing test established for the design pattern to take in to account the changes made by the system architects/engineers. User Users benefit from the use of design patterns because the software is typically delivered sooner than projects that do not incorporate the use of design patterns, and they are assumed that the system will work as designed because it was based on a system that was already proven to work properly.

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  • Resolving "PLS-00201: identifier 'DBMS_SYSTEM.XXXX' must be declared" Error

    - by Giri Mandalika
    Here is a failure sample. SQL set serveroutput on SQL alter package APPS.FND_TRACE compile body; Warning: Package Body altered with compilation errors. SQL show errors Errors for PACKAGE BODY APPS.FND_TRACE: LINE/COL ERROR -------- ----------------------------------------------------------------- 235/6 PL/SQL: Statement ignored 235/6 PLS-00201: identifier 'DBMS_SYSTEM.SET_EV' must be declared .. By default, DBMS_SYSTEM package is accessible only from SYS schema. Also there is no public synonym created for this package. So, the solution is to create the public synonym and grant "execute" privilege on DBMS_SYSTEM package to all database users or a specific user. eg., SQL CREATE PUBLIC SYNONYM dbms_system FOR dbms_system; Synonym created. SQL GRANT EXECUTE ON dbms_system TO APPS; Grant succeeded. - OR - SQL GRANT EXECUTE ON dbms_system TO PUBLIC; Grant succeeded. SQL alter package APPS.FND_TRACE compile body; Package body altered. Note that merely granting execute privilege is not enough -- creating the public synonym is as important to resolve this issue.

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  • Hello Operator, My Switch Is Bored

    - by Paul White
    This is a post for T-SQL Tuesday #43 hosted by my good friend Rob Farley. The topic this month is Plan Operators. I haven’t taken part in T-SQL Tuesday before, but I do like to write about execution plans, so this seemed like a good time to start. This post is in two parts. The first part is primarily an excuse to use a pretty bad play on words in the title of this blog post (if you’re too young to know what a telephone operator or a switchboard is, I hate you). The second part of the post looks at an invisible query plan operator (so to speak). 1. My Switch Is Bored Allow me to present the rare and interesting execution plan operator, Switch: Books Online has this to say about Switch: Following that description, I had a go at producing a Fast Forward Cursor plan that used the TOP operator, but had no luck. That may be due to my lack of skill with cursors, I’m not too sure. The only application of Switch in SQL Server 2012 that I am familiar with requires a local partitioned view: CREATE TABLE dbo.T1 (c1 int NOT NULL CHECK (c1 BETWEEN 00 AND 24)); CREATE TABLE dbo.T2 (c1 int NOT NULL CHECK (c1 BETWEEN 25 AND 49)); CREATE TABLE dbo.T3 (c1 int NOT NULL CHECK (c1 BETWEEN 50 AND 74)); CREATE TABLE dbo.T4 (c1 int NOT NULL CHECK (c1 BETWEEN 75 AND 99)); GO CREATE VIEW V1 AS SELECT c1 FROM dbo.T1 UNION ALL SELECT c1 FROM dbo.T2 UNION ALL SELECT c1 FROM dbo.T3 UNION ALL SELECT c1 FROM dbo.T4; Not only that, but it needs an updatable local partitioned view. We’ll need some primary keys to meet that requirement: ALTER TABLE dbo.T1 ADD CONSTRAINT PK_T1 PRIMARY KEY (c1);   ALTER TABLE dbo.T2 ADD CONSTRAINT PK_T2 PRIMARY KEY (c1);   ALTER TABLE dbo.T3 ADD CONSTRAINT PK_T3 PRIMARY KEY (c1);   ALTER TABLE dbo.T4 ADD CONSTRAINT PK_T4 PRIMARY KEY (c1); We also need an INSERT statement that references the view. Even more specifically, to see a Switch operator, we need to perform a single-row insert (multi-row inserts use a different plan shape): INSERT dbo.V1 (c1) VALUES (1); And now…the execution plan: The Constant Scan manufactures a single row with no columns. The Compute Scalar works out which partition of the view the new value should go in. The Assert checks that the computed partition number is not null (if it is, an error is returned). The Nested Loops Join executes exactly once, with the partition id as an outer reference (correlated parameter). The Switch operator checks the value of the parameter and executes the corresponding input only. If the partition id is 0, the uppermost Clustered Index Insert is executed, adding a row to table T1. If the partition id is 1, the next lower Clustered Index Insert is executed, adding a row to table T2…and so on. In case you were wondering, here’s a query and execution plan for a multi-row insert to the view: INSERT dbo.V1 (c1) VALUES (1), (2); Yuck! An Eager Table Spool and four Filters! I prefer the Switch plan. My guess is that almost all the old strategies that used a Switch operator have been replaced over time, using things like a regular Concatenation Union All combined with Start-Up Filters on its inputs. Other new (relative to the Switch operator) features like table partitioning have specific execution plan support that doesn’t need the Switch operator either. This feels like a bit of a shame, but perhaps it is just nostalgia on my part, it’s hard to know. Please do let me know if you encounter a query that can still use the Switch operator in 2012 – it must be very bored if this is the only possible modern usage! 2. Invisible Plan Operators The second part of this post uses an example based on a question Dave Ballantyne asked using the SQL Sentry Plan Explorer plan upload facility. If you haven’t tried that yet, make sure you’re on the latest version of the (free) Plan Explorer software, and then click the Post to SQLPerformance.com button. That will create a site question with the query plan attached (which can be anonymized if the plan contains sensitive information). Aaron Bertrand and I keep a close eye on questions there, so if you have ever wanted to ask a query plan question of either of us, that’s a good way to do it. The problem The issue I want to talk about revolves around a query issued against a calendar table. The script below creates a simplified version and adds 100 years of per-day information to it: USE tempdb; GO CREATE TABLE dbo.Calendar ( dt date NOT NULL, isWeekday bit NOT NULL, theYear smallint NOT NULL,   CONSTRAINT PK__dbo_Calendar_dt PRIMARY KEY CLUSTERED (dt) ); GO -- Monday is the first day of the week for me SET DATEFIRST 1;   -- Add 100 years of data INSERT dbo.Calendar WITH (TABLOCKX) (dt, isWeekday, theYear) SELECT CA.dt, isWeekday = CASE WHEN DATEPART(WEEKDAY, CA.dt) IN (6, 7) THEN 0 ELSE 1 END, theYear = YEAR(CA.dt) FROM Sandpit.dbo.Numbers AS N CROSS APPLY ( VALUES (DATEADD(DAY, N.n - 1, CONVERT(date, '01 Jan 2000', 113))) ) AS CA (dt) WHERE N.n BETWEEN 1 AND 36525; The following query counts the number of weekend days in 2013: SELECT Days = COUNT_BIG(*) FROM dbo.Calendar AS C WHERE theYear = 2013 AND isWeekday = 0; It returns the correct result (104) using the following execution plan: The query optimizer has managed to estimate the number of rows returned from the table exactly, based purely on the default statistics created separately on the two columns referenced in the query’s WHERE clause. (Well, almost exactly, the unrounded estimate is 104.289 rows.) There is already an invisible operator in this query plan – a Filter operator used to apply the WHERE clause predicates. We can see it by re-running the query with the enormously useful (but undocumented) trace flag 9130 enabled: Now we can see the full picture. The whole table is scanned, returning all 36,525 rows, before the Filter narrows that down to just the 104 we want. Without the trace flag, the Filter is incorporated in the Clustered Index Scan as a residual predicate. It is a little bit more efficient than using a separate operator, but residual predicates are still something you will want to avoid where possible. The estimates are still spot on though: Anyway, looking to improve the performance of this query, Dave added the following filtered index to the Calendar table: CREATE NONCLUSTERED INDEX Weekends ON dbo.Calendar(theYear) WHERE isWeekday = 0; The original query now produces a much more efficient plan: Unfortunately, the estimated number of rows produced by the seek is now wrong (365 instead of 104): What’s going on? The estimate was spot on before we added the index! Explanation You might want to grab a coffee for this bit. Using another trace flag or two (8606 and 8612) we can see that the cardinality estimates were exactly right initially: The highlighted information shows the initial cardinality estimates for the base table (36,525 rows), the result of applying the two relational selects in our WHERE clause (104 rows), and after performing the COUNT_BIG(*) group by aggregate (1 row). All of these are correct, but that was before cost-based optimization got involved :) Cost-based optimization When cost-based optimization starts up, the logical tree above is copied into a structure (the ‘memo’) that has one group per logical operation (roughly speaking). The logical read of the base table (LogOp_Get) ends up in group 7; the two predicates (LogOp_Select) end up in group 8 (with the details of the selections in subgroups 0-6). These two groups still have the correct cardinalities as trace flag 8608 output (initial memo contents) shows: During cost-based optimization, a rule called SelToIdxStrategy runs on group 8. It’s job is to match logical selections to indexable expressions (SARGs). It successfully matches the selections (theYear = 2013, is Weekday = 0) to the filtered index, and writes a new alternative into the memo structure. The new alternative is entered into group 8 as option 1 (option 0 was the original LogOp_Select): The new alternative is to do nothing (PhyOp_NOP = no operation), but to instead follow the new logical instructions listed below the NOP. The LogOp_GetIdx (full read of an index) goes into group 21, and the LogOp_SelectIdx (selection on an index) is placed in group 22, operating on the result of group 21. The definition of the comparison ‘the Year = 2013’ (ScaOp_Comp downwards) was already present in the memo starting at group 2, so no new memo groups are created for that. New Cardinality Estimates The new memo groups require two new cardinality estimates to be derived. First, LogOp_Idx (full read of the index) gets a predicted cardinality of 10,436. This number comes from the filtered index statistics: DBCC SHOW_STATISTICS (Calendar, Weekends) WITH STAT_HEADER; The second new cardinality derivation is for the LogOp_SelectIdx applying the predicate (theYear = 2013). To get a number for this, the cardinality estimator uses statistics for the column ‘theYear’, producing an estimate of 365 rows (there are 365 days in 2013!): DBCC SHOW_STATISTICS (Calendar, theYear) WITH HISTOGRAM; This is where the mistake happens. Cardinality estimation should have used the filtered index statistics here, to get an estimate of 104 rows: DBCC SHOW_STATISTICS (Calendar, Weekends) WITH HISTOGRAM; Unfortunately, the logic has lost sight of the link between the read of the filtered index (LogOp_GetIdx) in group 22, and the selection on that index (LogOp_SelectIdx) that it is deriving a cardinality estimate for, in group 21. The correct cardinality estimate (104 rows) is still present in the memo, attached to group 8, but that group now has a PhyOp_NOP implementation. Skipping over the rest of cost-based optimization (in a belated attempt at brevity) we can see the optimizer’s final output using trace flag 8607: This output shows the (incorrect, but understandable) 365 row estimate for the index range operation, and the correct 104 estimate still attached to its PhyOp_NOP. This tree still has to go through a few post-optimizer rewrites and ‘copy out’ from the memo structure into a tree suitable for the execution engine. One step in this process removes PhyOp_NOP, discarding its 104-row cardinality estimate as it does so. To finish this section on a more positive note, consider what happens if we add an OVER clause to the query aggregate. This isn’t intended to be a ‘fix’ of any sort, I just want to show you that the 104 estimate can survive and be used if later cardinality estimation needs it: SELECT Days = COUNT_BIG(*) OVER () FROM dbo.Calendar AS C WHERE theYear = 2013 AND isWeekday = 0; The estimated execution plan is: Note the 365 estimate at the Index Seek, but the 104 lives again at the Segment! We can imagine the lost predicate ‘isWeekday = 0’ as sitting between the seek and the segment in an invisible Filter operator that drops the estimate from 365 to 104. Even though the NOP group is removed after optimization (so we don’t see it in the execution plan) bear in mind that all cost-based choices were made with the 104-row memo group present, so although things look a bit odd, it shouldn’t affect the optimizer’s plan selection. I should also mention that we can work around the estimation issue by including the index’s filtering columns in the index key: CREATE NONCLUSTERED INDEX Weekends ON dbo.Calendar(theYear, isWeekday) WHERE isWeekday = 0 WITH (DROP_EXISTING = ON); There are some downsides to doing this, including that changes to the isWeekday column may now require Halloween Protection, but that is unlikely to be a big problem for a static calendar table ;)  With the updated index in place, the original query produces an execution plan with the correct cardinality estimation showing at the Index Seek: That’s all for today, remember to let me know about any Switch plans you come across on a modern instance of SQL Server! Finally, here are some other posts of mine that cover other plan operators: Segment and Sequence Project Common Subexpression Spools Why Plan Operators Run Backwards Row Goals and the Top Operator Hash Match Flow Distinct Top N Sort Index Spools and Page Splits Singleton and Range Seeks Bitmaps Hash Join Performance Compute Scalar © 2013 Paul White – All Rights Reserved Twitter: @SQL_Kiwi

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