how to defragment

Redis suddenly hung up, unable to start, look log log, found reported short read or OOM loading DB. Unrecoverable error, aborting nowSolution: [Root@localhost ~]# rm-f/var/lib/redis/dump.rdb[Root@localhost ~]# rm-f/var/run/redis.pid[root@localhost ~]# Service Redis start Question Two The Windows version of Redis allocates a memory mapped heap for sharing withThe forked process used for persistence operations. In order to share thisMemory, Windows allocates from the system paging file a portio

A large amount of deleted data will inevitably result in discontinuous white space in the data file, and when the data is inserted, the white space will be exploited. There are different ways to defragment the storage engine. MyISAM You can do this in the following ways:Mysql> Show table status from test like ' testusers ' \g 1. Row *************************** .... Rows:3 Avg_row_length:45 Data_free:40 ..... Because in the middle of the deletion, so

dynamic RAM across processes using explicitly allocated shared memory regions (E Ither with Ashmem or Gralloc).On many occasions, Android uses the specified area of allocated memory to share the same dynamic memory across processes.2. Allocating and reclaiming App MemoryAllocating and reclaiming memoryHere is some facts about how to Android allocates then reclaims memory from your app:Here are some system policies for recovering and allocating memory:1) The Dalvik heap for each process are cons

:+USECONCMARKSWEEPGC -xx:cmsfullgcsbeforecompaction=5-xx:+ Usecmscompactatfullcollection-xx:cmsfullgcsbeforecompaction: Because the concurrent collector does not compress and defragment the memory space, it can produce "fragmentation" after a period of time, which makes the operation less efficient. This value sets how many times a GC is run to compress and defragment the memory space.-xx:+usecmscompactatfu

DBREINDEX: rebuilding one or more indexes in the specified database4. DBCC INDEXDEFRAG: Defragment a clustered index or secondary index that specifies a table or viewFive, optimize the index:1. Rebuild index (DBCC DBREINDEX) 2, Index Tuning Wizard3. Defragment the clustered index and secondary index fragmentation for the specified table or view (DBCC INDEXEFRAG)How to create an indexThe CREATE INDEX statem

-the-go, something the CMS Collector only does during full STW collections (G1 algorithm has an advantage that it can defragment heap memory without interfering with heap memory allocations, prevent heap memory fragmentation, and CMS will defragment heap memory only at STW) . Large Heaps has been a fairly contentious area over the past few years with many developers moving away from the Singl E JVM per mac

WIN8 System Computer blue screen how to solve? The specific methods are as follows: 1. Restart your computer, and when a list of available operating systems appears, press F8, and on the Windows Advanced Options menu screen, select Last Known Good Configuration and press ENTER. 2, restore the BIOS to the factory default settings, conditions can be upgraded to refresh the BIOS. 3, remove the memory, clean the slot, with the eraser finger, and plug in tight; Check the memory quality is probl

:+useconcmarksweepgc-xx:cmsfullgcsbeforecompaction=5-xx:+ Usecmscompactatfullcollection-xx:cmsfullgcsbeforecomPaction: Because the concurrent collector does not compress and defragment the memory space, it can produce "fragmentation" after a period of time, which makes the operation less efficient. This value sets how many times a GC is run to compress and defragment the memory space. -xx:+usecmscompactatfu

the hardware driver installed correctly, the general change of hardware is not likely, so you can also consider to delete this backup, The file is located in the C:windowsdriver cachei386 directory, the name is Driver.cab, you can delete it directly, usually this file size about hundred megabytes. The other is Windows Help files, the general user will not use these files, save for no purpose, so delete these files can be completely, these files are generally saved in the C:windowshelp folder, d

correctly, the general change of hardware is not likely, so you can also consider to delete this backup, The file is located in the C:windowsdriver cachei386 directory, the name is Driver.cab, you can delete it directly, usually this file size about hundred megabytes. The other is Windows Help files, the general user will not use these files, save for no purpose, so delete these files can be completely, these files are generally saved in the C:windowshelp folder, directly deleted. since Window

footprint, you can set virtual memory for 512-768MB (memory + virtual memory and generally higher than the normal occupation of 256MB can). 1GB memory, according to the actual use of memory footprint, you can set virtual memory for 128-512MB (memory + virtual memory and generally higher than the normal occupation of 256-512MB can). Memory is 2G and above, you can generally disable virtual memory (with software restrictions can set a small amount of virtual memory, such as 128MB). Some people wh

\.default\software\microsoft\windows\currentversion\policies\network "NoEntireNetwork ", and set its value to" 1 ". 　　 Mouse Menu Increase the Defragment disk option for the right key menu of the drive Create a primary key "Defrag" under Hkey_local_machine\software\classes\drive\shell, and in the right window, change the "default" value to: Defragment disk, and in this primary key "NewWindow" Create a

recommended setting is 1k~16k Query_cache_wlock_invalidateThis parameter mainly involves the MyISAM engine, if a client adds a write lock to a table, a query request is made by another client, and the query statement has a corresponding query cache record, whether it is allowed to read the query cached recordset information directly, or to wait for the release of the write lock. The default setting is 0, which is allowed; Maintenance Query for defragmentation of the ease area After the quer

This and delete all the records saved in the partition, and then reinsert them, with the same effect. It can be used to defragment partitions. ALTER TABLE T1 REBUILD PARTITION (P0, p1); Optimizing Partitions If you delete a large number of rows from a partition, or if you make many changes to a row with a variable length (that is, a column with Varchar,blob, or text type), You can use the ALTER TABLE ... OPTIMIZE PARTITION "to reclaim unused space an

; Show variables like ' thread_cache_size ';+ ——————-+ ——-+| variable_name | Value |+ ——————-+ ——-+| Thread_cache_size | 64 |+ ——————-+ ——-+ The server in the example is still pretty healthy. Vii. Query caching (queries cache) Mysql> show global status like ' qcache% ';+ ————————-+ ——— –+| variable_name | Value |+ ————————-+ ——— –+| Qcache_free_blocks | 22756 || Qcache_free_memory | 76764704 || Qcache_hits | 213028692 || Qcache_inserts | 208894227 || Qcache_lowmem_prunes | 4010916 || qcache_n

This problem occurs when the delete is followed by the condition. Delete from table_name WHERE condition When you delete data, the amount of space that the datasheet occupies does not change. When you do not follow the conditions directly delete. Delete from table_name The data is cleared, and the space of the datasheet becomes 0. If a large portion of the table data has been deleted, or there are many changes and variable-length table rows (varchar tables, VARBINARY, blobs, or text

. Check and fix the hard drive error, start--Run---Enter CHKDSK/R (/previous space)--Determine--"check this volume on the next system reboot", and then restart the computer. 5, defragment the disk. My Computer-right-click the drive that will defragment the disk-Properties-Tools-Select the defragmented disk open the Disk Defragmenter window-analysis-defragmentation-the system starts to finish and the system

Our computer sometimes in C or D disk or in the root directory of our U disk has a folder named found.000, there are some suffixes named Chk file. Under C:windows There are many strange files that start with FFF, and the size is all 0 bytes. Also some found folders occupy a lot of space, hundreds of m even a few g! what exactly are these, can be deleted? The following figure: Definition: When the computer shuts down abnormally, the defragment