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  • ?Oracle Database 12c????TTnn TMON??redo??????

    - by Liu Maclean(???)
    ?Oracle 11g? Data Guard?redo?????????3???????: ARCi (FAL – archived redo shipping, ping, local only archivals) NSAi (async) 12.1 name: TTnn , NSSi (sync) –– live redo shipping ????12c?? ??TTnn  ??TT00?????async ???redo??? ???????TMON????Redo transport monitor? SQL> select banner from v$version where rownum=1; BANNER -------------------------------------------------------------------------------- Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production SQL> select program,pid from v$process where program like '%TMON%' or Program like '%TT%'; PROGRAM PID ------------------------------ ---------- ORACLE.EXE (TMON) 7 ORACLE.EXE (TT00) 24 ??????? ?11g ???NSAi async redo ship?????????LGWR?????????,?????redo ????; ???12c?TTnn???redo???????LGWR? ???  ??????async redo ship ??redo??! 11g?: 12c?

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  • NSUndoManager with Core Data - Redo not working

    - by CJ
    I have a Core Data document-based app which support undo/redo via the built-in NSUndoManager associated with the NSManagedObjectContext. I have a few actions set up which perform numerous tasks within Core Data, wrap all these tasks into an undo group via beginUndoGrouping/endUndoGrouping, and are processed by the NSUndoManager. Undo works fine. I can perform several successive actions, and each then undo each one of them successively and my app's state is maintained correctly. However, the "Redo" menu item is never enabled. This means that the NSUndoManager is telling the menu that there are no items to redo. I am wondering why the NSUndoManager is seemingly forgetting about items once they are undone, and not allowing redos to occur? One thing I should mention is that I'm disabling undo registration after a document is opened/created. When I perform an action, I call enableUndoRegistration, beginUndoGrouping, perform the action, then call processPendingChanges, setActionName:, endUndoGrouping, and finally disableUndoRegistration. This makes sure that only specific actions are undoable, and any other data changes I make outside of these go unnoticed to the NSUndoManager. This may be a part of the issue, but if so I'm wondering why it's affecting redo? Thanks in advance.

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  • Oracle EE 11.2g: how to generate fresh new redo logs

    - by Aikanaro
    Hi, In the company I work for we are heavy users of vmware machines. Almost all our projects are developed inside a virtual environment up to the point where we have to deploy them into a production system. While in development, some colleagues of mine deleted the redo log files for Oracle in the hopes of gaining some free space. Now they are unable to start the database instance. Is there a way of generating a fresh new redo log so that the instance can be started? This is urgent and even though I'm currently googling for an answer I have yet to find it. Thanks in advance.

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  • ???Flashback Log???????Redo Log?

    - by Liu Maclean(???)
    ????????????????????redo log?   RVWR( Recovery Writer)?3s??flashback generate buffer??block before image?????????? ?????block change???RVWR??block before image ?flashback log? ?????????,Oracle???????????before image????????,????????flashback database logs?????   ???????????,????? ??????????????????,???????????before image?????shared pool??flashback log buffer?,RVWR??????flashback log buffer??????????? ?DBWR???????????????,DBWR?????buffer header??FBA(Flashback Byte Address)?flashback log buffer?????????? ???? ?????? ??? ????????????? , RVWR???????????(flashback markers)?flashback database logs?? ????(flashback markers)?????????????Oracle??flashback ??????????  ??????????, Oracle ??????(flashback markers)????????????flashback database log???????????block image; ??Oracle ???????(forward recovery)?????????????????SCN?????? flashback markers for example: **** Record at fba: (lno 1 thr 1 seq 1 bno 4 bof 8184) **** RECORD HEADER: Type: 3 (Skip) Size: 8132 RECORD DATA (Skip): **** Record at fba: (lno 1 thr 1 seq 1 bno 4 bof 52) **** RECORD HEADER: Type: 7 (Begin Crash Recovery Record) Size: 36 RECORD DATA (Begin Crash Recovery Record): Previous logical record fba: (lno 1 thr 1 seq 1 bno 3 bof 316) Record scn: 0x0000.00000000 [0.0] **** Record at fba: (lno 1 thr 1 seq 1 bno 3 bof 8184) **** RECORD HEADER: Type: 3 (Skip) Size: 7868 RECORD DATA (Skip): **** Record at fba: (lno 1 thr 1 seq 1 bno 3 bof 316) **** RECORD HEADER: Type: 2 (Marker) Size: 300 RECORD DATA (Marker): Previous logical record fba: (lno 0 thr 0 seq 0 bno 0 bof 0) Record scn: 0x0000.00000000 [0.0] Marker scn: 0x0000.0060e024 [0.6348836] 06/13/2012 15:56:35 Flag 0x0 Flashback threads: 1, Enabled redo threads 1 Recovery Start Checkpoint: scn: 0x0000.0060e024 [0.6348836] 06/13/2012 15:56:12 thread:1 rba:(0x80.180.10) Flashback thread Markers: Thread:1 status:0 fba: (lno 1 thr 1 seq 1 bno 2 bof 8184) Redo Thread Checkpoint Info: Thread:1 rba:(0x80.180.10) **** Record at fba: (lno 1 thr 1 seq 1 bno 2 bof 8184) **** RECORD HEADER: Type: 3 (Skip) Size: 8168 RECORD DATA (Skip): End-Of-Thread reached ????????????????block change ????before image????????flashback log?? ?????block change???flashback log record ????????? redo log???!????flashback log ???????before image ? redo log??? change vector ?  Oracle?????????????????????????????????????,??????I/O??????????????: ??hot block??,Oracle???????????block image?????; Oracle ?????????(flashback barriers)???????????????,flashback barriers???????(???15??),??????????(flashback barriers)????(flashback markers)????????? ????, ??????change?????, ???????????????????????????, ?15????????????????????flashback log????????before image?????????????,?????????????????????,?????????????? ????????,??????????????(flashback barriers), flashback barriers???????,?????15????? ?????flashback barriers????????(flashback markers)???????????????,???????????????????(????barriers?????)??????block image ,????????????????????????????????? ??????????flashback log????redo log????! ????,????????????????, ?????????? 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> create table flash_maclean (t1 varchar2(200)) tablespace users; Table created. SQL> insert into flash_maclean values('MACLEAN LOVE HANNA'); 1 row created. SQL> commit; Commit complete. SQL> startup force; ORACLE instance started. Total System Global Area 939495424 bytes Fixed Size 2233960 bytes Variable Size 713034136 bytes Database Buffers 218103808 bytes Redo Buffers 6123520 bytes Database mounted. Database opened. SQL> update flash_maclean set t1='HANNA LOVE MACLEAN'; 1 row updated. commit; Commit complete. SQL> alter system checkpoint; System altered. SQL> select dbms_rowid.rowid_block_number(rowid),dbms_rowid.rowid_relative_fno(rowid) from flash_maclean; DBMS_ROWID.ROWID_BLOCK_NUMBER(ROWID) DBMS_ROWID.ROWID_RELATIVE_FNO(ROWID) ------------------------------------ ------------------------------------ 140431 4 datafile 4 block 140431 ??RDBA rdba: 0x0102248f (4/140431) SQL> ! ps -ef|grep rvwr|grep -v grep oracle 26695 1 0 15:56 ? 00:00:00 ora_rvwr_G11R23 SQL> oradebug setospid 26695 Oracle pid: 20, Unix process pid: 26695, image: [email protected] (RVWR) SQL> ORADEBUG DUMP FBTAIL 1; Statement processed. To dump the last 2000 flashback records , ??ORADEBUG DUMP FBTAIL 1????????2000?????? SQL> oradebug tracefile_name /s01/orabase/diag/rdbms/g11r23/G11R23/trace/G11R23_rvwr_26695.trc ? TRACE?????????block? before image **** Record at fba: (lno 1 thr 1 seq 1 bno 55 bof 2564) **** RECORD HEADER: Type: 1 (Block Image) Size: 28 RECORD DATA (Block Image): file#: 4 rdba: 0x0102248f Next scn: 0x0000.00000000 [0.0] Flag: 0x0 Block Size: 8192 BLOCK IMAGE: buffer rdba: 0x0102248f scn: 0x0000.00609044 seq: 0x01 flg: 0x06 tail: 0x90440601 frmt: 0x02 chkval: 0xc626 type: 0x06=trans data Hex dump of block: st=0, typ_found=1 Dump of memory from 0x00002B1D94183C00 to 0x00002B1D94185C00 2B1D94183C00 0000A206 0102248F 00609044 06010000 [.....$..D.`.....] 2B1D94183C10 0000C626 00000001 00014AD4 0060903A [&........J..:.`.] 2B1D94183C20 00000000 00320002 01022488 00090006 [......2..$......] 2B1D94183C30 00000CC8 00C00340 000D0542 00008000 [[email protected].......] 2B1D94183C40 006040BC 000F000A 00000920 00C002E4 [.@`..... .......] 2B1D94183C50 0017048F 00002001 00609044 00000000 [..... ..D.`.....] 2B1D94183C60 00000000 00010100 0014FFFF 1F6E1F77 [............w.n.] 2B1D94183C70 00001F6E 1F770001 00000000 00000000 [n.....w.........] 2B1D94183C80 00000000 00000000 00000000 00000000 [................] Repeat 500 times 2B1D94185BD0 00000000 00000000 2C000000 4D120102 [...........,...M] 2B1D94185BE0 454C4341 4C204E41 2045564F 4E4E4148 [ACLEAN LOVE HANN] 2B1D94185BF0 01002C41 43414D07 4E41454C 90440601 [A,...MACLEAN..D.] Block header dump: 0x0102248f Object id on Block? Y seg/obj: 0x14ad4 csc: 0x00.60903a itc: 2 flg: E typ: 1 - DATA brn: 0 bdba: 0x1022488 ver: 0x01 opc: 0 inc: 0 exflg: 0 Itl Xid Uba Flag Lck Scn/Fsc 0x01 0x0006.009.00000cc8 0x00c00340.0542.0d C--- 0 scn 0x0000.006040bc 0x02 0x000a.00f.00000920 0x00c002e4.048f.17 --U- 1 fsc 0x0000.00609044 bdba: 0x0102248f data_block_dump,data header at 0x2b1d94183c64 =============== tsiz: 0x1f98 hsiz: 0x14 pbl: 0x2b1d94183c64 76543210 flag=-------- ntab=1 nrow=1 frre=-1 fsbo=0x14 fseo=0x1f77 avsp=0x1f6e tosp=0x1f6e 0xe:pti[0] nrow=1 offs=0 0x12:pri[0] offs=0x1f77 block_row_dump: tab 0, row 0, @0x1f77 tl: 22 fb: --H-FL-- lb: 0x2 cc: 1 col 0: [18] 4d 41 43 4c 45 41 4e 20 4c 4f 56 45 20 48 41 4e 4e 41 end_of_block_dump SQL> select dump('MACLEAN LOVE HANNA',16) from dual; DUMP('MACLEANLOVEHANNA',16) -------------------------------------------------------------------- Typ=96 Len=18: 4d,41,43,4c,45,41,4e,20,4c,4f,56,45,20,48,41,4e,4e,41 ???????????????????????,??flashback log??before image????????? create table flash_maclean1 (t1 int) tablespace users; SQL> select vs.name, ms.value 2 from v$mystat ms, v$sysstat vs 3 where vs.statistic# = ms.statistic# 4 and vs.name in ('redo size','db block changes'); NAME VALUE ---------------------------------------------------------------- ---------- db block changes 0 redo size 0 SQL> select name,value from v$sysstat where name like 'flashback log%'; NAME VALUE ---------------------------------------------------------------- ---------- flashback log writes 49 flashback log write bytes 9306112 SQL> begin 2 for i in 1..5000 loop 3 update flash_maclean1 set t1=t1+1; 4 commit; 5 end loop; 6 end; 7 / PL/SQL procedure successfully completed. SQL> select vs.name, ms.value 2 from v$mystat ms, v$sysstat vs 3 where vs.statistic# = ms.statistic# 4 and vs.name in ('redo size','db block changes'); NAME VALUE ---------------------------------------------------------------- ---------- db block changes 20006 redo size 3071288 SQL> select name,value from v$sysstat where name like 'flashback log%'; NAME VALUE ---------------------------------------------------------------- ---------- flashback log writes 52 flashback log write bytes 10338304 ??????????? ??hot block,???20006 ?block changes???? ??? 3000k ?redo log ? ??1000k? flashback log ?

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  • Oracle physical standby database received redo has not been applied

    - by Arthur Aoife
    Hi, I followed the steps in oracle documentation on creation of a physical standby database. The link to the configuration steps, http://download.oracle.com/docs/cd/B28359_01/server.111/b28294/create_ps.htm#i63561 When I perform "Step 4 Verfiy that received redo has been applied." my query result is not as expected, following is the result, SQL SELECT SEQUENCE#,APPLIED FROM V$ARCHIVED_LOG ORDER BY SEQUENCE#; SEQUENCE# APP 5 NO 6 NO 7 NO 8 NO 4 rows selected. Appreciate any advice on how to proceed, thanks.

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  • How can you add a UIGestureRecognizer to a UIBarButtonItem as in the common undo/redo UIPopoverContr

    - by SG
    Problem In my iPad app, I cannot attach a popover to a button bar item only after press-and-hold events. But this seems to be standard for undo/redo. How do other apps do this? Background I have an undo button (UIBarButtonSystemItemUndo) in the toolbar of my UIKit (iPad) app. When I press the undo button, it fires it's action which is undo:, and that executes correctly. However, the "standard UE convention" for undo/redo on iPad is that pressing undo executes an undo but pressing and holding the button reveals a popover controller where the user selected either "undo" or "redo" until the controller is dismissed. The normal way to attach a popover controller is with presentPopoverFromBarButtonItem:, and I can configure this easily enough. To get this to show only after press-and-hold we have to set a view to respond to "long press" gesture events as in this snippet: UILongPressGestureRecognizer *longPressOnUndoGesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPressOnUndoGesture:)]; //Broken because there is no customView in a UIBarButtonSystemItemUndo item [self.undoButtonItem.customView addGestureRecognizer:longPressOnUndoGesture]; [longPressOnUndoGesture release]; With this, after a press-and-hold on the view the method handleLongPressOnUndoGesture: will get called, and within this method I will configure and display the popover for undo/redo. So far, so good. The problem with this is that there is no view to attach to. self.undoButtonItem is a UIButtonBarItem, not a view. Possible solutions 1) [The ideal] Attach the gesture recognizer to the button bar item. It is possible to attach a gesture recognizer to a view, but UIButtonBarItem is not a view. It does have a property for .customView, but that property is nil when the buttonbaritem is a standard system type (in this case it is). 2) Use another view. I could use the UIToolbar but that would require some weird hit-testing and be an all around hack, if even possible in the first place. There is no other alternative view to use that I can think of. 3) Use the customView property. Standard types like UIBarButtonSystemItemUndo have no customView (it is nil). Setting the customView will erase the standard contents which it needs to have. This would amount to re-implementing all the look and function of UIBarButtonSystemItemUndo, again if even possible to do. Question How can I attach a gesture recognizer to this "button"? More specifically, how can I implement the standard press-and-hold-to-show-redo-popover in an iPad app? Ideas? Thank you very much, especially if someone actually has this working in their app (I'm thinking of you, omni) and wants to share...

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  • Implements an Undo/Redo in MVC

    - by bnabilos
    Hello, I have a Java application and I want to implement an Undo/Redo option. the value that I want to stock and that I want to be able to recover is an integer. My Class Model implements the interface StateEditable and I have to redefine the 2 functions restoreState(Hashtable<?, ?> state) and storeState(Hashtable<Object, Object> state) but I don't know what to put on them. It will be really great if somebody can help me to do that. These are the first lines of my Model class, the value that I want to do an undo/redo on it is value public class Model extends Observable implements StateEditable { private int value = 5; private UndoManager undoRedo = new UndoManager(); final UndoableEditListener editListener = new UndoableEditListener() { public void undoableEditHappened(UndoableEditEvent evt) { undoRedo.addEdit(evt.getEdit()); } }; @Override public void restoreState(Hashtable<?, ?> state) { } @Override public void storeState(Hashtable<Object, Object> state) { } }

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  • ??Data Guard???????Redo GAP

    - by JaneZhang(???)
      ?Oracle Data Guard?,Redo Gap??????????????????redo????????????,?????????redo??????????,?????????????:ARC:????MRP:Media Recovery Process,????????redoRFS:Remote File Server ,???????????redo??FAL:Fetch Archive Log????:?????????gap?,??????????gap?????:Oracle 11.2.0.2 on Linux 5.????:1.?????????????:Primary:MAX(SEQUENCE#)--------------           86Standby:MAX(SEQUENCE#)--------------           862. ??????,??gap:????????: #ifconfig eth0 down???????switch logfile:SQL>alter system switch logfile;SQL>alter system switch logfile;...Primary:MAX(SEQUENCE#)--------------           96????alert log?????????????:TNS-00513: Destination host unreachable   nt secondary err code: 101   nt OS err code: 0Error 12543 received logging on to the standbyFAL[server, ARCp]: Error 12543 creating remote archivelog file 'STANDBY'FAL[server, ARCp]: FAL archive failed, see trace file.ARCH: FAL archive failed. Archiver continuingORACLE Instance orcl - Archival Error. Archiver continuing.3.??????????????,????????????:mv *.arc ../4. ???????:#ifconfig eth0 up5.??,???ARC???????????????????MRP???gap??gap fetching.??alert log:Thu Mar 29 19:58:49 2012Media Recovery Waiting for thread 1 sequence 87 (in transit) <====  ?????,??87...Thu Mar 29 20:08:45 2012...Media Recovery Waiting for thread 1 sequence 94Thu Mar 29 20:11:01 2012RFS[61]: Assigned to RFS process 13643RFS[61]: Opened log for thread 1 sequence 97 dbid 1285401128 branch 757620395Archived Log entry 80 added for thread 1 sequence 97 rlc 757620395 ID 0x4c9d8928 dest 2:Thu Mar 29 20:11:02 2012RFS[62]: Assigned to RFS process 13645RFS[62]: Selected log 4 for thread 1 sequence 98 dbid 1285401128 branch 757620395Thu Mar 29 20:11:02 2012Primary database is in MAXIMUM PERFORMANCE modeRe-archiving standby log 4 thread 1 sequence 98Thu Mar 29 20:11:02 2012Archived Log entry 81 added for thread 1 sequence 98 ID 0x4c9d8928 dest 1:RFS[63]: Assigned to RFS process 13647RFS[63]: Selected log 4 for thread 1 sequence 99 dbid 1285401128 branch 757620395Thu Mar 29 20:11:05 2012Fetching gap sequence in thread 1, gap sequence 94-96 <===========?gap...6.??MRP?trace,?????MRP ??fetching gap:MRP trace:*** 2012-03-29 20:08:45.375 4265 krsh.cMedia Recovery Waiting for thread 1 sequence 94*** 2012-03-29 20:11:05.543*** 2012-03-29 20:11:05.543 4265 krsh.cFetching gap sequence in thread 1, gap sequence 94-96 <==========MRP?gap.Redo shipping client performing standby login*** 2012-03-29 20:11:05.593 4595 krsu.cLogged on to standby successfullyClient logon and security negotiation successful!7.????????????,???RFS????????, MRP ????????apply.Thu Mar 29 20:12:06 2012RFS[64]: Assigned to RFS process 13649RFS[64]: Opened log for thread 1 sequence 94 dbid 1285401128 branch 757620395Archived Log entry 82 added for thread 1 sequence 94 rlc 757620395 ID 0x4c9d8928 dest 2:Thu Mar 29 20:12:06 2012RFS[65]: Assigned to RFS process 13651RFS[65]: Opened log for thread 1 sequence 95 dbid 1285401128 branch 757620395Thu Mar 29 20:12:06 2012RFS[66]: Assigned to RFS process 13653RFS[66]: Opened log for thread 1 sequence 96 dbid 1285401128 branch 757620395Archived Log entry 83 added for thread 1 sequence 95 rlc 757620395 ID 0x4c9d8928 dest 2:Archived Log entry 84 added for thread 1 sequence 96 rlc 757620395 ID 0x4c9d8928 dest 2:Thu Mar 29 20:12:16 2012Media Recovery Log /home/oracle/arch1/standby/1_94_757620395.arcMedia Recovery Log /home/oracle/arch1/standby/1_95_757620395.arcMedia Recovery Log /home/oracle/arch1/standby/1_96_757620395.arcMedia Recovery Log /home/oracle/arch1/standby/1_97_757620395.arcMedia Recovery Log /home/oracle/arch1/standby/1_98_757620395.arc????:????????,????gap???,???ARC?????????gap??,????????????MRP???apply log??????gap,???????FAL????? ?:?11g,??????ARC??????RFS?MRP?????????????gap. 8. ????????MRP??FAL??gap??,????????????,??MRP?trace???:FAL[client, MRP0],?????FAL??? *** 2012-03-29 21:18:15.964 4265 krsh.cError 1031 received logging on to the standby*** 2012-03-29 21:18:15.964 4265 krsh.cFAL[client, MRP0]: Error 1031 connecting to PRIMARY for fetching gap sequence

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  • How to implement Undo and Redo feature in as3

    - by Swati Singh
    I am going to create an application in that i have to implement an Undo and Redo feature. In the application there will be multiple objects located on stage and user can customize the position of the objects. But when user clicks on Undo the object go back to their default position and after clicking on redo object will move on the new position. So my question is how can i apply these feature in my application? Is there any library or any third party classes? Can some one help me? Thanks in advance.

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  • How does undo/redo basically work on iPhone OS?

    - by mystify
    My app doesn't use Core Data yet. Is it true that I must use Core Data for undo/redo? And: How does the user do the undo/redo? I've never seen it in action, and never ever used it. Don't know how I should do it if I wanted to. There's no undo/redo button anywhere. Yet they say it has undo/redo. So how does the user trigger this?

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  • Commit in SQL

    - by PRajkumar
    SQL Transaction Control Language Commands (TCL)                                           (COMMIT) Commit Transaction As a SQL language we use transaction control language very frequently. Committing a transaction means making permanent the changes performed by the SQL statements within the transaction. A transaction is a sequence of SQL statements that Oracle Database treats as a single unit. This statement also erases all save points in the transaction and releases transaction locks. Oracle Database issues an implicit COMMIT before and after any data definition language (DDL) statement. Oracle recommends that you explicitly end every transaction in your application programs with a COMMIT or ROLLBACK statement, including the last transaction, before disconnecting from Oracle Database. If you do not explicitly commit the transaction and the program terminates abnormally, then the last uncommitted transaction is automatically rolled back.   Until you commit a transaction: ·         You can see any changes you have made during the transaction by querying the modified tables, but other users cannot see the changes. After you commit the transaction, the changes are visible to other users' statements that execute after the commit ·         You can roll back (undo) any changes made during the transaction with the ROLLBACK statement   Note: Most of the people think that when we type commit data or changes of what you have made has been written to data files, but this is wrong when you type commit it means that you are saying that your job has been completed and respective verification will be done by oracle engine that means it checks whether your transaction achieved consistency when it finds ok it sends a commit message to the user from log buffer but not from data buffer, so after writing data in log buffer it insists data buffer to write data in to data files, this is how it works.   Before a transaction that modifies data is committed, the following has occurred: ·         Oracle has generated undo information. The undo information contains the old data values changed by the SQL statements of the transaction ·         Oracle has generated redo log entries in the redo log buffer of the System Global Area (SGA). The redo log record contains the change to the data block and the change to the rollback block. These changes may go to disk before a transaction is committed ·         The changes have been made to the database buffers of the SGA. These changes may go to disk before a transaction is committed   Note:   The data changes for a committed transaction, stored in the database buffers of the SGA, are not necessarily written immediately to the data files by the database writer (DBWn) background process. This writing takes place when it is most efficient for the database to do so. It can happen before the transaction commits or, alternatively, it can happen some times after the transaction commits.   When a transaction is committed, the following occurs: 1.      The internal transaction table for the associated undo table space records that the transaction has committed, and the corresponding unique system change number (SCN) of the transaction is assigned and recorded in the table 2.      The log writer process (LGWR) writes redo log entries in the SGA's redo log buffers to the redo log file. It also writes the transaction's SCN to the redo log file. This atomic event constitutes the commit of the transaction 3.      Oracle releases locks held on rows and tables 4.      Oracle marks the transaction complete   Note:   The default behavior is for LGWR to write redo to the online redo log files synchronously and for transactions to wait for the redo to go to disk before returning a commit to the user. However, for lower transaction commit latency application developers can specify that redo be written asynchronously and that transaction do not need to wait for the redo to be on disk.   The syntax of Commit Statement is   COMMIT [WORK] [COMMENT ‘your comment’]; ·         WORK is optional. The WORK keyword is supported for compliance with standard SQL. The statements COMMIT and COMMIT WORK are equivalent. Examples Committing an Insert INSERT INTO table_name VALUES (val1, val2); COMMIT WORK; ·         COMMENT Comment is also optional. This clause is supported for backward compatibility. Oracle recommends that you used named transactions instead of commit comments. Specify a comment to be associated with the current transaction. The 'text' is a quoted literal of up to 255 bytes that Oracle Database stores in the data dictionary view DBA_2PC_PENDING along with the transaction ID if a distributed transaction becomes in doubt. This comment can help you diagnose the failure of a distributed transaction. Examples The following statement commits the current transaction and associates a comment with it: COMMIT     COMMENT 'In-doubt transaction Code 36, Call (415) 555-2637'; ·         WRITE Clause Use this clause to specify the priority with which the redo information generated by the commit operation is written to the redo log. This clause can improve performance by reducing latency, thus eliminating the wait for an I/O to the redo log. Use this clause to improve response time in environments with stringent response time requirements where the following conditions apply: The volume of update transactions is large, requiring that the redo log be written to disk frequently. The application can tolerate the loss of an asynchronously committed transaction. The latency contributed by waiting for the redo log write to occur contributes significantly to overall response time. You can specify the WAIT | NOWAIT and IMMEDIATE | BATCH clauses in any order. Examples To commit the same insert operation and instruct the database to buffer the change to the redo log, without initiating disk I/O, use the following COMMIT statement: COMMIT WRITE BATCH; Note: If you omit this clause, then the behavior of the commit operation is controlled by the COMMIT_WRITE initialization parameter, if it has been set. The default value of the parameter is the same as the default for this clause. Therefore, if the parameter has not been set and you omit this clause, then commit records are written to disk before control is returned to the user. WAIT | NOWAIT Use these clauses to specify when control returns to the user. The WAIT parameter ensures that the commit will return only after the corresponding redo is persistent in the online redo log. Whether in BATCH or IMMEDIATE mode, when the client receives a successful return from this COMMIT statement, the transaction has been committed to durable media. A crash occurring after a successful write to the log can prevent the success message from returning to the client. In this case the client cannot tell whether or not the transaction committed. The NOWAIT parameter causes the commit to return to the client whether or not the write to the redo log has completed. This behavior can increase transaction throughput. With the WAIT parameter, if the commit message is received, then you can be sure that no data has been lost. Caution: With NOWAIT, a crash occurring after the commit message is received, but before the redo log record(s) are written, can falsely indicate to a transaction that its changes are persistent. If you omit this clause, then the transaction commits with the WAIT behavior. IMMEDIATE | BATCH Use these clauses to specify when the redo is written to the log. The IMMEDIATE parameter causes the log writer process (LGWR) to write the transaction's redo information to the log. This operation option forces a disk I/O, so it can reduce transaction throughput. The BATCH parameter causes the redo to be buffered to the redo log, along with other concurrently executing transactions. When sufficient redo information is collected, a disk write of the redo log is initiated. This behavior is called "group commit", as redo for multiple transactions is written to the log in a single I/O operation. If you omit this clause, then the transaction commits with the IMMEDIATE behavior. ·         FORCE Clause Use this clause to manually commit an in-doubt distributed transaction or a corrupt transaction. ·         In a distributed database system, the FORCE string [, integer] clause lets you manually commit an in-doubt distributed transaction. The transaction is identified by the 'string' containing its local or global transaction ID. To find the IDs of such transactions, query the data dictionary view DBA_2PC_PENDING. You can use integer to specifically assign the transaction a system change number (SCN). If you omit integer, then the transaction is committed using the current SCN. ·         The FORCE CORRUPT_XID 'string' clause lets you manually commit a single corrupt transaction, where string is the ID of the corrupt transaction. Query the V$CORRUPT_XID_LIST data dictionary view to find the transaction IDs of corrupt transactions. You must have DBA privileges to view the V$CORRUPT_XID_LIST and to specify this clause. ·         Specify FORCE CORRUPT_XID_ALL to manually commit all corrupt transactions. You must have DBA privileges to specify this clause. Examples Forcing an in doubt transaction. Example The following statement manually commits a hypothetical in-doubt distributed transaction. Query the V$CORRUPT_XID_LIST data dictionary view to find the transaction IDs of corrupt transactions. You must have DBA privileges to view the V$CORRUPT_XID_LIST and to issue this statement. COMMIT FORCE '22.57.53';

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  • Oracle redo log performance degradation when inserting

    - by Aldarund
    I have a oracle 11g database. I'm testing in for inserts. The database running in noarchive mode. I have 3 redo log configured, each 2gb. I'm trying to insert data into test table. At begin it goes fine with 15k ins/second. I make a commit after 200 inserts. But after about 1.3m inserted records it become really slow, about 1-2k ins/second. As i noticed in resource explorer at this point we have filled all redo logs and so the inserts from this points work slow. So my question is why it become so slow when it fills redo logs, even if i commit each 200 records. And how this situation can be fixed ( except the turning off logging completely at inserts)

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  • Should I redo an abandoned project with Lightswitch?

    - by Elson
    I had a small project that I was doing on the side. It was basically a couple of forms linked to a DB. Access was out, because it was a specifically meant to be a web application. Being a small project I used ASP.NET Dynamic Data, but, for various reasons, the project ended before deployment. I met the client recently, and he said there was a need for it still. I'm considering restarting the project with Dynamic Data, but I've seen some Lightswitch demos, and was suitably impressed with the BETA. I will wait for RTM if I use it, but is it a good idea to use Lightswitch to replace the Dyanmic Data? The amount of work I put into the Dynamic Data site isn't really an issue. Additional information: It's a system that tracks production in a small factory, broken down by line, machine, section and will generate reports. I would guess that the data structure will remain fairly constant over time, but that the reporting requirements will grow. The other thing is that the factory is part of a larger group, and I'm hopeful that, if this system succeeds, similar work with be forthcoming for other factories.

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  • Is this an acceptable approach to undo/redo in Python?

    - by Codemonkey
    I'm making an application (wxPython) to process some data from Excel documents. I want the user to be able to undo and redo actions, even gigantic actions like processing the contents of 10 000 cells simultaneously. I Googled the topic, and all the solutions I could find involves a lot of black magic or is overly complicated. Here is how I imagine my simple undo/redo scheme. I write two classes - one called ActionStack and an abstract one called Action. Every "undoable" operation must be a subclass of Action and define the methods do and undo. The Action subclass is passed the instance of the "document", or data model, and is responsible for committing the operation and remembering how to undo the change. Now, every document is associated with an instance of the ActionStack. The ActionStack maintains a stack of actions (surprise!). Every time actions are undone and new actions are performed, all undone actions are removed for ever. The ActionStack will also automatically remove the oldest Action when the stack reaches the configurable maximum amount. I imagine the workflow would produce code looking something like this: class TableDocument(object): def __init__(self, table): self.table = table self.action_stack = ActionStack(history_limit=50) # ... def delete_cells(self, cells): self.action_stack.push( DeleteAction(self, cells) ) def add_column(self, index, name=''): self.action_stack.push( AddColumnAction(self, index, name) ) # ... def undo(self, count=1): self.action_stack.undo(count) def redo(self, count=1): self.action_stack.redo(count) Given that none of the methods I've found are this simple, I thought I'd get the experts' opinion before I go ahead with this plan. More specifically, what I'm wondering about is - are there any glaring holes in this plan that I'm not seeing?

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  • Oracle Logical Standby redo generation

    - by DCookie
    Oracle 10.2.0.4 database with a logical standby on Win2K3. Recently a rather large delete operation was carried out on the production instance. I'm experiencing difficulty with the logical standby, in that it gets a couple of hundred (58M size) archive logs into the operation and the apply process fails with an out-of-memory error. Unfortunately, every time it fails it has to restart the apply from the beginning of the transaction. This is taking a couple of days each time. Anyway, in trying to resolve this problem, I've noticed that each archive log from the production system generates 5 or 6 log switches on the standby. I don't understand why this should be. Anyone have any ideas? A related question that I've not found the answer for: does anyone know if the logical standby must be running in archivelog mode? I really don't have a need to keep the logs.

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  • Undo/Redo Support for Table Changes in WPF RichTextBox

    - by Jeff
    As part of an editor project, I need to add functionality to the WPF RichTextBox control to allow the user to perform operations on a table. One of those operations is to apply a new width value to one or more columns of the table. I have a function that is applying a new Width value to the TableColumn objects in question, and the table is resizing itself nicely. However, I've noticed that the column-width change operation does not seem to be added to the undo stack. In other words, if a user types something, then changes a column width, then selects undo, the RichTextBox control undoes the user's typing. Undo and redo don't seem to be picking up the property change on the TableColumn object. Is there some way to make this operation occur in a way that it actually is undoable/redoable?

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  • Looking to redo a static website

    - by moorecats
    I have been asked to help redo my non-profit website. I would like to make it look better. What would be the best way to do this? I have some technical background and can learn. I have looked at various options such as Joomla, word press and so on but I am not certain on how to create a good UI for it. I have also looked at Ruby and such, which I think may be overkill for a static page such as this. I haven't done any programming etc in a few years, but I figure this may be an opportunity to get back into it.

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  • NSUndoManager, Core Data and selective undo/redo

    - by Combat
    I'm working on a core data application that has a rather large hierarchy of managed objects similar to a tree. When a base object is created, it creates a few child objects which in turn create their own child objects and so on. Each of these child objects may gather information using NSURLConnections. Now, I'd like to support undo/redo with the undoManager in the managedObjectContext. The problem is, if a user creates a base object, then tries to undo that action, the base object is not removed. Instead, one or more of the child objects may be removed. Obviously this type of action is unpredictable and unwanted. So I tried disabling undo registration by default. I did this by calling disableUndoRegistration: before anything is modified in the managedObjectContext. Then, enabling undo registration before base operations such as creating a base object the again re-disabling registrations afterwords. Now when i try to undo, I get this error: undo: NSUndoManager 0x1026428b0 is in invalid state, undo was called with too many nested undo groups Thoughts?

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  • Core Data deleteObject: sets attributes to nil

    - by SG1
    I am implementing an undo/redo mechanism in my app. This works fine for lots of cases. However, I can't undo past deleteObject:. the object is correctly saved in the undo queue, and I get it back and reinsterted into the Core Data stack just fine when calling undo. The problem is that all it's attributes are getting set to nil when I delete it. I have an entity "Canvas" with a to-many relationship called "graphics" to a "Graphic" entity, which has its inverse set to "canvas". Deleting a Graphic, then inserting it back, doesn't work. Here's the code (the redo method is basically the same): - (void)deleteGraphic:(id)aGraphic { //NSLog(@"undo drawing"); //Prepare the undo/redo [self.undoManager beginUndoGrouping]; [self.undoManager setActionName:@"Delete Graphic"]; [[self.detailItem valueForKey:@"graphics"] removeObject:aGraphic]; [[self managedObjectContext] deleteObject:aGraphic]; //End undo/redo [self.undoManager registerUndoWithTarget:self selector:@selector(insertGraphic:) object:aGraphic]; [self.undoManager endUndoGrouping]; NSLog(@"graphics are %@", [self sortedGraphics]); //Update drawing [self.quartzView setNeedsDisplay]; } and here's the wierdness: Before delete: graphics are ( <NSManagedObject: 0x1cc3f0> (entity: Graphic; id: 0x1c05f0 <x-coredata:///Graphic/t840FE8AD-F2E7-4214-822F-7994FF93D4754> ; data: { canvas = 0x162b70 <x-coredata://A919979E-75AD-474D-9561-E0E8F3388718/Canvas/p20>; content = <62706c69 73743030 d4010203 04050609 0a582476 65727369 6f6e5424 746f7059 24617263 68697665 7258246f 626a6563 7473>; frameRect = nil; label = nil; order = 1; path = "(...not nil..)"; traits = "(...not nil..)"; type = Path; }) After redo: graphics are ( <NSManagedObject: 0x1cc3f0> (entity: Graphic; id: 0x1c05f0 <x-coredata:///Graphic/t840FE8AD-F2E7-4214-822F-7994FF93D4754> ; data: { canvas = nil; content = nil; frameRect = nil; label = nil; order = 0; path = nil; traits = nil; type = nil; }), You can see it's the same object, just totally bleached by Core Data. The relationship delete rouls apparently have nothing to do with it as I've set them to "No Action" in a test.

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  • NSUndoManager won't undo editing of a NSMutableDictionary

    - by xon1c
    Hi, I'm experiencing problems with the undo operation. The following code won't undo an removeObjectForKey: operation but the redo operation setObject:ForKey: works. - (void) insertIntoDictionary:(NSBezierPath *)thePath { [[[window undoManager] prepareWithInvocationTarget:self] removeFromDictionary:thePath]; if(![[window undoManager] isUndoing]) [[window undoManager] setActionName:@"Save Path"]; NSLog(@"Object id is: %d and Key id is: %d", [currentPath objectAtIndex:0], thePath); [colorsForPaths setObject:[currentPath objectAtIndex:0] forKey:thePath]; } - (void) removeFromDictionary:(NSBezierPath *)thePath { [[[window undoManager] prepareWithInvocationTarget:self] insertIntoDictionary:thePath]; if(![[window undoManager] isUndoing]) [[window undoManager] setActionName:@"Delete Path"]; NSLog(@"Object id is: %d and Key id is: %d", [[colorsForPaths allKeys] objectAtIndex:0], thePath); [colorsForPaths removeObjectForKey:thePath]; } The output on the console looks like: // Before setObject:ForKey: Object id is: 1184384 and Key id is: 1530016 // Before removeObjectForKey: UNDO Object id is: 2413664 and Key id is: 1530016 I don't get why the Object id is different although the Key id remains the same. Is there some special undo/redo handling of NSMutableDictionary objects? thx xonic

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  • Undo/Redo using Memento: Stack, Queue or just LinkedList?

    - by serhio
    What is the best having when implementing Memento pattern (for Undo/Redo) in witch collection to Keep Mementos? Basically, I need this(c = change, u = undo, r = redo): 0 *c -1 0 *c -2 -1 0 *c -3 -2 -1 0 <u -2 -1 0 1 *c -3 -2 -1 0 Variants: LinkedList - possible in principle, maybe not optimized. Queue - not adapted for this task, IMO. Stack - not adapted for undo AND redo; Double Stack - maybe optimal, but can't control the undo maximum size.

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  • Best way to Start Over on my Dreamhost server?

    - by obsessive
    I have made a mess of my Dreamhost slice and want to know if there's a way to clean install/fresh install/wipe everything and start over? Is there a shell script to do this or would I have to do it through the Dreamhost admin panel or even contact Dreamhost to get them to do it for me? Any advice is appreciated, I'm not sure the best way to proceed. Thanks!

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