Do you know that there is an upper limit on the size of Oracle data files?

Traditional relational database , Although when the client interacts with the database , Are dealing with various caches , however " data " Or do you want to drop the plate , File is his storage form , Since it's a document , There will be capacity limitations , that ,Oracle What is the limit of the data file size ？

Refer to some information , Each data file can contain at most 2^22-1 Data blocks , This limitation is due to Oracle Of Rowid Use in 22 On behalf of Block Number , this 22 At most, it can only represent 2^22-1 Data blocks . Of course ,Oracle10g Introduced large file tablespaces ,Oracle You can use 32 On behalf of Block Number , therefore , Each file in the large file table space can hold at most 4G individual Block.

P. S. 《 What is? rowid？》

If it's the default 8k Data blocks , A data file contains 2^22-1 Data blocks , His file size , Namely 2^22-1 * 8k / 1024 /1024 = 32G, That is, the maximum can not exceed 32G. The corresponding ,

4k The maximum data file of data block shall not exceed 16G.
16k‍ The maximum data file of data block shall not exceed 64G.
32k The maximum data file of data block shall not exceed 128G.
64k The maximum data file of data block shall not exceed 256G.

If it is a large file table space , By default 8k Data blocks , Data files can achieve 32T, If it is 32k A block of data , The data file size can reach 128T.

although , According to the above calculation , There is an upper limit on the size of data files , however , If the maximum capacity of a single file supported by the operating system is less than this value , It is limited to the maximum capacity of the operating system . in addition ,Windows Can only be used in 2k、4K、8K、16K Block size , Maximum block capacity , Will be slightly smaller .

Related to data files is db_files Parameters , He specifies the maximum number of files that an instance can create . This value can be modified , But only after restarting the instance , Will take effect .db_files Set too low , It may cause the problem that new data files cannot be added . Set too high , It will consume more memory resources . For how to set ,《Database Administrator’s Guide》 Gives guidance , But it still has to be combined with the actual situation ,

https://docs.oracle.com/en/database/oracle/oracle-database/19/admin/managing-data-files-and-temp-files.html#GUID-BB7D8910-FCAE-4DAD-BDE5-B5EE35C69C6B

therefore , Including not limited to Oracle And the size of the data file , When we encounter the actual demand scenario , Understand these limitations , It helps us to choose the most suitable scheme .

Reference material ,

http://www.eygle.com/archives/2007/07/oracle_datafile_limit.html

https://www.modb.pro/db/386663?utm_source=index_ai

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