> Could you explain how postgresql can "fall victim" the filesystem hole
> mechanism? Just hoping to force actual storage allocation, or hoping
> to discourage fragmentation?
Most Unix filesystems will not allocate disk blocks until you write in
them. If you just seek out past end-of-file, the file pointer is moved
but the blocks are unallocated. This is how 'ls' can show a 1gb file
that only uses 4k of disk space.
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