wait event

Oracle wait event-1. Knowledge about waiting events 1. The concept of waiting events from the source is introduced from ORACLE 7.0.12, with approximately 100 waiting events. In ORACLE 8.0, this number has increased to approximately 150, with

DB Name db Id Instance Inst Num Release Cluster Host------------ ----------- ------------ -------- ----------- ------- ------------Lixora 1409317108 Lixora 1 9.2.0.1.0 NO lixora-dataSnap Id snap time Sessions curs/sess Comment------- ----------------

Repeat the library cache lock wait event in Oracle 11 GB, 11 glibrary From the example below, we can see that re-Compilation of objects in the production database will lead to library cache lock, so we should try to avoid compiling objects during

I insisted on reading three sets of RAC AWR every day and summarized it. Query the SQL statement of the log wait event: 9i: Select * from V $ event_name where name like '% log %'; (about 14)10g: Select name, wait_class from V $ event_name where

Note 1:TYPICALLYDBWR have to free up some buffers when you want to read something from the disk. During This process there is chances that you'll be a waiting for your local buffer (i.e blocks dirtied/invalidated by R session) to is written to disk.

DB file Sequential read:Website Explanation:This event signifies, the user process is reading a buffer to the SGA buffer cache and is waiting for a physical I/Ocall to return. A sequential read is a single-block read.The single block I/Os is usually

Instance-level monitoring, open and low overhead:To create a base table:create table sys.sesstat_history tablespace eol asselect c.username,        c.osuser,       a.sid,        c.serial#,       c.paddr,        c.process,       c.logon_time,    

Today is, and we will continue to complete the waiting event series. What is: dbfilesequentialread :? Simply put, oracle needs to read a single piece of data, and other sessions are waiting. There are three parameters p1, which are the file to be

In recent cases, the database and alterdatabaseopenresetlogs commands under 10.2.0.5.12 have been waiting. The alert_sid.log information is: settingrecoverytargetincarnationto2. The waiting event obtained from v $ session. event is enq: DM. In

Oracle9i statspack report analysis direct path read wait event, oracle9istatspackDB Name DB Id Instance Inst Num Release Cluster Host-------------------------------------------------------------------------LIXORA 1409317108 LIXORA 1 9.2.0.1.0 NO

DB file Parallel readWebsite Explanation:This happens during recovery. It can also happen during buffer prefetching, as an optimization (rather than performing multiple single-block reads). Database blocks, need to being changed as part of recovery

 1. directpath reads description In versions earlier than Oracle 11g, if a full table scan is performed on a large table, the wait event is: DB file scattered read; in 11g, if a full table scan is performed on a large table, wait event is: direct

1. CPU Time Normal, ranked first in waiting events Num_cpu_sockets Number of physical CPUs Num_cpu_cores CPU Number of cores Num_cpus Number of logical CPUs 2. buffer busy waits (buffer busy wait/ read by other session)

1. AWR report for the first 7 days of 2018-09-26 (Oracle usage is 4,022.34/6,179.76/24=2.71% during this period)The most notable problem is the log file sync wait event, which is accompanied by the log file parallel write wait event, which is also

Cache buffers LRU ChainReasonHigh load cache throughput, inefficient SQL statements (full table scan, or incorrect index range scans)DBWR write speed is too slow, the foreground process spends a lot of time holding latch to find free buffer.The

As we all know, the Oracle high water level line marks that all blocks below this line are in Oracle format. In other words, all blocks below this line are used by Oracle. Usually As we all know, the Oracle high water level line marks that all

In WinCE or Windows Moblie development, a large amount of batch processing work is often submitted to the Worker Thread. When the batch processing is completed, or when the process fails or is abnormal, You need to notify the interface process (UI

1. View a blocking session for a waiting eventSelect Event,blocking_session,sql_id,count (*) from Dba_hist_active_sess_history Ashwhere Sample_time>=to_timestamp (' 2013-06-24 12:25:00 ', ' yyyy-mm-dd hh24:mi:ss ')and Sample_timeand event= '

As you can see from the following example, the recompilation of objects in the production database causes the library cache lock, so you should try to avoid compiling objects during peak business hours. If there is a complex dependency in the

The HW lock is provided to prevent multiple processes from simultaneously modifying HWM. The process to move HWM must obtain the HW lock. If a contention occurs during the acquisition of the HW lock, the system waits for the enq: HW-contention event.