C. Features Introduced in Ingres 10.0 : DBMS Server Enhancements : File Allocation Improvements (UNIX)
 
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File Allocation Improvements (UNIX)
Ingres can now take advantage of the "fallocate" function of certain file systems, which reserves (pre-allocates) disk space as files are written. When applied to table files, pre-allocation may slow creation of the table somewhat, but subsequent reading of the table may be faster, since the table is more likely to be allocated sequentially on disk. The improvement is most likely to be seen when table scans are common, such as in data warehousing installations with large tables.
To take advantage of pre-allocation, the table should be created with the ALLOCATION= and EXTEND= parameters set to reflect the expected table size. The default allocation and extend values are too small to be useful for pre-allocation.
This improvement adds a new configuration parameter to the DBMS Server component:
fallocate
Enables use of file pre-allocation through fallocate. If the file system does not support fallocate or an equivalent, the parameter setting does not matter (is OFF).
Default: OFF