Hi, I found following item in the Developer FAQ. I don't see why this is related to developers. ------------------------------------------------------------------------------------ Why aren't there more compression options when dumping tables?
pg_dump's built-in compression method is gzip. The primary alternative, bzip2, is normally far too slow to be useful when dumping large tables. The two main alternatives regularly proposed for better built-in compression at good speeds are LZO and LZMA/LZMA2/XZ. LZO is released under the GPL, incompatible with PostgreSQL. The LZMA2 code has been released into the public domain, but the C port is a secondary one (C++ is the main development focus) whose code quality hasn't seemed appropriate for this project. And this whole area has traditionally been filled with patent issues that go beyond just the restrictions of the software license. Another limitation on changing this is that pg_dump output is intended to be archivable, so we had better be prepared to support compression methods for a very long time. The "latest and greatest" compression method is exactly what we *don't* want. See the archives for an idea what characteristics an alternate compression tool would need to have in order to be considered for use in core PostgreSQL. ------------------------------------------------------------------------------------ -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese: http://www.sraoss.co.jp -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
