clear buffer cache

the output of the free command on Linux. here is the result of the free run, with a total of 4 rows. For convenience, I added a column number. This can be seen as a two-dimensional array fo (free output). For example: FO[2][1] = 24677460

1. buffer is a buffer. 2. cache is a high-speed cache, which is divided into library cache, data dictionary cache, and database buffer. Cache Buffer cache high-speed cache, used to cache data read from the hard disk, reduce disk I/O. 3. buffer has a

1, the role of Buffer cache To improve the IO performance of disk devices, we use memory as the cache for disk devices. When a user operates a disk device, the data is first written to memory, and then the dirty data in memory is refreshed to disk

　　For a will embark on the "system operation" or the more tall still work "system tuning", if this does not have a good relationship with these two buddies, the pit is not only memory, but also the pit is that you take the tune of the money but dry

Objective JavaScript is designed for browsers to handle Unicode-encoded strings well, but not for binary or non-Unicode-encoded data. Node.js inherits the language features of JavaScript while expanding the JavaScript language, providing a buffer

The buffer cache settings are evolving as the Oracle version is upgraded. The Oracle 8i is set using Db_block_buffers, which represents the number of memory blocks that can be contained in the buffer cache, and the Oracle 9i is set using

Let's take a big picture first:  SQL statement used: BYS @ ocm1> select dbms_rowid.rowid_relative_fno (rowid) file #, dbms_rowid.rowid_block_number (rowid) block #, deptno from bys. test; FILE # BLOCK # DEPTNO ------------------------------ 4 391 10

The cache and buffer are two different concepts, simply put, the cache is accelerated "read", and buffer is buffered "write", the former solve the problem of reading, save the data read from the disk, the latter is to solve the write problem, save

Buffer (buffered)Buffer is designed to increase the speed of data exchange between memory and the hard disk (or other I/O devices). Based on the read/write design of the disk. Centralize the scattered write operations, reducing disk fragmentation

DescriptionLike other operating systems, Linux has implemented a very efficient memory management mechanism, but any process that destroys the system's memory, then you have to clean it up, Linux provides a better way to flush \ Clear the RAM