[ZODB-Dev] Some interesting (to some:) numbers

[Jim Fulton]

Our recent discussion of compression made me curious so I did some
analysis of pickle sizes in one of our large databases. This is for a
content management system.  The database is packed weekly.  It doesn't
include media, which are in blobs.

There were ~19 million transaction in the database and around 130
million data records. About 60% of the size was taken up by BTrees.
Compressing pickles using zlib with default compression reduced the
pickle sizes by ~58%. The average uncompressed record size was 1163
bytes.  The average compressed size was ~493 bytes.

This is probably enough of a savings to make compression interesting.

Jim

--
Jim Fulton