On 7 Dec 2009, at 2:27pm, Nick Shaw wrote: > When the file exceeds a certain size, I DELETE a specific number of > records, then VACUUM the file to get the size back below required > limits. This works fine, however what happens to the VACUUM command if > there is insufficient disk space for SqLite to write out the cleaned up > copy of the database? I assume it will fail, but the documentation > doesn't specifically say how much disk space is required during a VACUUM > operation. The newly vacuumed file's size should end up being equal to > or less than the existing file's size, so I assume I'll need at least > the current database's size of disk space free, but will it ever require > more space than that to perform the VACUUM (e.g. from other temporary > files)?
Because there is no documentation about how these things work, even if we answered your question, the answer might change in a future version. For example, VACUUM might go from rewrite-in-place to writing a fresh copy of the entire file. It should definitely do this if it notices database corruption while VACUUMing. In similar situations to yours I have instead created a huge pointless file to take up disk space pointlessly. The routine that recovers data deletes this huge file (giving it guaranteed free space to work) then does the recovery, then creates a huge dummy file again. This technique means that not only will your automated system have a chance to work but you will also be able to free up enough space to do emergency recovery stuff manually. Simon. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
