Klint Gore wrote:
I'm playing around with storing custom preprocessed data structures within Large Objects. I'd like to be able to write a custom function that will, within a query, let me select out particular bytestrings from the middle of a Large Object (within C, I think 'lo_lseek' and 'lo_read' would get me what I want).
According to http://www.postgresql.org/docs/8.3/static/lo-funcs.html , the functions are server side too

Thanks for the link; still trying to figure out how to use these functions, though.

The link that you sent suggests that these commands are really only useful for writing out data to server-side files, which isn't so much what I want. What I really want is to lo_open a file, then lo_lseek to a particular address and loread a constant number of bytes (to be returned as the query result), then lo_close the file.

I'm currently stuck on the easy part: lo_open always returns 0, which gives me "ERROR: invalid large-object descriptor: 0" when I try to use it with loread.

Any further thoughts?

Thanks,
Adam

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