I wrote: > > From: Tom Lane [mailto:t...@sss.pgh.pa.us] > > > I wrote: > > > "Etsuro Fujita" <fujita.ets...@lab.ntt.co.jp> writes: > > >> I have a question. I think it would be also better to extend the syntax > > >> for the SQL COPY command in the same way, ie, > > >> COPY foo from '/home/pgsql/decompress.sh /home/pgsql/foo.csv.gz |' with > > >> format 'csv' > > > > > Yeah, sure --- that case is already superuser-only, so why not give it > > > the option of being a popen instead of just fopen. > > > > BTW, one thought that comes to mind is that such an operation is > > extremely likely to fail under environments such as SELinux. That's > > not necessarily a reason not to do it, but we should be wary of > > promising that it will work everywhere. Probably a documentation note > > about this would be enough. > > OK I'll revise the patch.
I've revised the patch. In this version a user can specify hooks for pre- and
post-processor executables for COPY and \copy in the follwoing way:
$ echo '/bin/gunzip -c $1' > decompress.sh
$ chmod +x decompress.sh
In the case of the COPY command,
postgres=# COPY foo FROM '/home/pgsql/decompress.sh /home/pgsql/foo.csv.gz'
WITH (format 'csv');
Also, in the case of the \copy instruction,
postgres=# \copy foo from '/home/pgsql/decompress.sh /home/pgsql/foo.csv.gz'
with (format 'csv')
As shown in the example above, I've assumed that the syntax for this option for
e.g., the COPY command is:
COPY table_name FROM 'progname filename' WITH ...
COPY table_name TO 'progname filename' WITH ...
Here, progname for COPY IN is the user-supplied program that takes filename as
its argument and that writes on standard output. Also, prgoname for COPY OUT is
the user-supplied program that reads standard input and writes to filename taken
as its argument. This makes simple the identification and verification of
progname and filename.
Todo:
* Documentation including documentation note about the limitation for
environments such as SELinux mentioned by Tom.
* More test
Any comments and suggestions are welcomed.
Thanks,
Best regards,
Etsuro Fujita
copy-popen-20121114.patch
Description: Binary data
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