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The largest database file that Berkeley DB can handle depends on the page size -selected by the application. Berkeley DB stores database file page numbers as -unsigned 32-bit numbers and database file page sizes as unsigned 16-bit -numbers. Using the maximum database page size of 65536, this results in -a maximum database file size of 2⁴⁸ (256 terabytes). The -minimum database page size is 512 bytes, which results in a minimum -maximum database size of 2⁴¹ (2 terabytes).

The largest database file Berkeley DB can support is potentially further limited -if the host system does not have filesystem support for files larger than -2³², including the ability to seek to absolute offsets within -those files.

The largest key or data item that Berkeley DB can support is 2³², -or more likely limited by available memory. Specifically, while key and -data byte strings may be of essentially unlimited length, any one of -them must fit into available memory so that it can be returned to the -application. As some of the Berkeley DB interfaces return both key and data -items to the application, those interfaces will require that any -key/data pair fit simultaneously into memory. Further, as the access -methods may need to compare key and data items with other key and data -items, it may be a requirement that any two key or two data items fit -into available memory. Finally, when writing applications supporting -transactions, it may be necessary to have an additional copy of any data -item in memory for logging purposes.

+ The largest database file that Berkeley DB can handle + depends on the page size selected by the application. Berkeley + DB stores database file page numbers as unsigned 32-bit + numbers and database file page sizes as unsigned 16-bit + numbers. Using the maximum database page size of 65536, this + results in a maximum database file size of + 2⁴⁸ (256 terabytes). The + minimum database page size is 512 bytes, which results in a + minimum maximum database size of + 2⁴¹ (2 terabytes). +

Note

+ In order to store petabytes of data you can use + multiple database files. +

+ The largest database file Berkeley DB can support is + potentially further limited if the host system does not have + filesystem support for files larger than + 2³², including the ability to + seek to absolute offsets within those files. +

+ The largest key or data item that Berkeley DB can support + is 2³², or more likely limited by + available memory. Specifically, while key and data byte + strings may be of essentially unlimited length, any one of + them must fit into available memory so that it can be returned + to the application. As some of the Berkeley DB interfaces + return both key and data items to the application, those + interfaces will require that any key/data pair fit + simultaneously into memory. Further, as the access methods may + need to compare key and data items with other key and data + items, it may be a requirement that any two key or two data + items fit into available memory. Finally, when writing + applications supporting transactions, it may be necessary to + have an additional copy of any data item in memory for logging + purposes. +

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Home - Disk space requirements + Disk space + requirements