How to restore damaged online logs
Corrupt non-current online logs
It is clear that online logs are divided into current online logs and non-current online logs. the corruption of Non-current online logs is relatively simple. Generally, you can solve the problem by using the clear command.
1. Start the database, encountered a ORA-00312 or ORA-00313 error, such
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: 'd: \ Oracle \ ORADATA \ TEST \ REDO01.LO
Case 2: The log is switched and the history log is overwritten (only incomplete recovery is possible)
1) Simulation Environment
sql> INSERT into SCOTT.TB01 values (777);
1 row created.
sql> INSERT INTO SCOTT.TB01 values (888);
1 row created.
Sql> commit;
Commit complete.
Sql> col status for A10
Sql> select * from V$log;
group# thread# sequence# BYTES members archived STATUS first_change#
---------- ---------- ---------- ---------- ---------- --------- ---------- ------------- --------
Today I saw an article about how to avoid using the switch and use an enum, after looking at the feeling that the author is very good, here to share.
Original address: Avoid switch! Use enum!
Recently I is about to refactor the some code crap4j pointed me to. When I realized most of this code was some kind of switch-case or If-else-cascade, I remembered Daniel´s Post and decided To obey those four rules.This the post is supposed to give some inspiration in how to get rid of the code like:
Swit
corrupted.
More detailed information can be seen from the alert file
2. View V$log View
Sql> select Group#,sequence#,archived,status from V$log;
group# sequence# Archived STATUS
---------- ---------- -------- ----------------
1 1 YES INACTIVE
2 2 YES INACTIVE
3 3 NO Current
As you can see, the group is out of the current state and has been archived.
3. Rebuild the log file with clear command
Sql>alter Dat
Oracle
Experience Summary:
The online logs are divided into current and non current online logs, and the corruption of the non-current online log is relatively simple, and the problem can be resolved by the clear command.
Corrupt non-current online log:
1, start the database, encountered ORA-00312 or ORA-00313 error, such as:
Ora-00313:open failed for members of log Group 4 of thread 1
Ora-00312:online Log 3 thread 1: '/opt/oracle/db04/oradata/orcl/redo03.log '
From here we know that log Gro
) ABC active, then the same first line d=b*c can be optimized out
8.5.3 B6 principle similar to 8.5.1, slightly
8.5.4 B3 principle similar to 8.5.1, slightly
8.5.5
1) a[i]=b A is set to inactive, B is set to active, affecting all references to array a
2) A=b[i] A is set to inactive, B is set to active and affects all references to array b
3) A=*b A is set to inactive
Label:Oracle Number of connections too many release mechanism sqlplus/nolog open sqlplus connect/ As sysdba Use DBA authority to login oracle Show parameter resource_limit shows whether resource qualification is on, value is true is on, false is off Alter system set resource_limit=true If not turned on, use this command to turn on resource-limited functionality NBSP;NBSP create profile profilename limit connect_time idle_time 30 Create ProfileName any start
() method, and if all of the activity is not visible (all performed OnStop ()), do what we want to do.2. LogicCustom application, where you define a global HashMap, define two methods, method one addactivitystatus (activity activity) to manage the state of the activity, method two Isallactivityalive () is used to query whether all activity is active.In each activity of the Onresume () method, call Addactivitystatus (activity activity) to set the state of the current activity to true activation
The life cycle of an iOS app—————————————————————————— the entry function for the entire application-(BOOL) Application: (UIApplication *) application didfinishlaunchingwithoptions: (nsdictionary *) launchOptions{return YES;}—————————————————————————— never active to Active state-(void) Applicationwillresignactive: (uiapplication *) application{Sent when the application are about to move from active to inactive state. This can occur for certain types
ORA-03113: end-of-file on communication channel address the loss of an INACTIVE log group simulation on www.2cto.com today, encountering ORA-03113 SQL> select group #, archived, status from v $ log; GROUP # arc status ---------- --- ---------------- 1 no current 2 yes inactive 3 yes inactive SQL> select member from v $ logfile where group # = 3; MEMBER ----------
Key: 5 Status: AVAILABLE Compressed: NO Tag: TAG20121214T062943
Piece Name:/oracle/app/db1/dbs/0fnsqnsl_1_1
Control File Included: Ckp SCN: 2779647876 Ckp time: 14-DEC-12
3. The log status when creating tablespaces and test data is as follows:
SQL> select group #, archived, sequence #, status from v $ Log;
GROUP # arc sequence # STATUS
---------------------------------------
1 YES 14 INACTIVE
2 YES 13 INACTIV
-(BOOL) Application: (UIApplication *) application willfinishlaunchingwithoptions: (nsdictionary *) launchOptions
{
NSLog (@"① tells the agent process to start but has not yet entered the state save");
return YES;
}
② tells the agent to start the basic Completion program ready to start running
-(BOOL) Application: (UIApplication *) application didfinishlaunchingwithoptions: (nsdictionary *) launchOptions
{
Self.window = [[UIWindow alloc] initwithframe:[[uis
mode_rgb_p = 0,Mode_bgr_p = 1,Mode_rgb_s = 2,Mode_bgr_s = 3,S3cfb_set_polarity (fbdev );// Set the register xf800_0004, which is in the [7], [6], [5], and [4] bits.// Ivclk [7] controls the polarity of the vclk active edge.// 0 = video data is fetched at vclk falling edge// 1 = video data is fetched at vclk rising edge// Ihsync [6] specifies the hsync pulse polarity.// 0 = normal// 1 = inverted// Ivsync [5] specifies the vsync pulse polarity.// 0 = normal// 1 = inverted// Ivden [4] specifies th
pages
(2) inactive clean pages
(3) inactive dirty pages
2. The role of kswapd:
(1) identify several pages in advance and disconnect the Mappings of these pages so that these pages are transferred from the active status to the inactive status.
(2) Write inactive dirty pages into swap devices, make them
, the size of the header of a request does not exceed 1 K, but generally the system page size is greater than 1 K, set the page size here.
You can use the getconf pagesize command to obtain the page size.
Nginx uses the buffer client_header_buffer_size by default to read the header value. If the request header is too large, it uses large_client_header_buffers to read
If the setting is too small,
When the HTTP header is too large (usually the cookie is too large), the error 400 nginx 400 bad requ
size or hash bucket size prompt is displayed, we need to increase the value of server_names_hash_max_size.Client_header_buffer_size 128 k; # set the buffer size of the client request header according to the system page size. the page size can be obtained using the getconf PAGESIZE command.Large_client_header_buffers 4 128 k; #4 indicates the number and k indicates the size. the default value is 4 k. Apply for 4 128 KB. When the http URI is too long or the request header is too large, 414 Reques
large, depending on your message stream and the life of your queue manager. However, many files are active. The activity file contains the log entries required to restart the queue manager. The number of active log files is usually the same as the number of master log files defined in the configuration file.
Checkpoint is a key event that controls whether a log file is active. The WebSphere MQ checkpoint is a set of logs that contain information about the successful restart of the queue manager
connections allowed by each process. Theoretically, the maximum number of connections per nginx server is worker_processes * worker_connections.
6. keepalive_timeout 60;
Keepalive timeout.
7. client_header_buffer_size 4 k;
The buffer size of the client request header, which can be set based on your system page size. Generally, the size of a request header does not exceed 1 k, but generally the system page size is greater than 1 k, set the page size here.
You can use the getconf PAGESIZE command
, the system performance decreases sharply. At this time, the system is running very slowly or in the paused state. this state is also called thrashing)
1. command format:
Copy codeThe code is as follows:Vmstat [-a] [-n] [-S unit] [delay [count]Vmstat [-s] [-n] [-S unit]Vmstat [-m] [-n] [delay [count]Vmstat [-d] [-n] [delay [count]Vmstat [-p disk partition] [-n] [delay [count]Vmstat [-f]Vmstat [-V]
2. command functions:
Used to display virtual memory information
3. command parameters:
-A: Displa
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