[ovs-dev] [PATCH 0/2] raft: Reduce memory consumption by freeing unnecessary json objects.

[Ilya Maximets]

In short, database snapshot stored inside the raft module is
a huge json object.  E.g. in ovn-heater scale tests with 270 MB
on-disk Southbound DB, json object of a snapshot takes 1.6 GB of
RAM out of total 3.8 GB of the RSS of an ovsdb-server process.

This change is targeted to free that json object as soon as it
no longer needed and keep its serialized version instead.

Testing on a bit smaller cluster with 97 MB of on-disk database
showed *58%* of the memory consumption decrease with this change.

More details on testing and implementation in commit messages.

Ilya Maximets (2):
  json: Add support for partially serialized json objects.
  raft: Don't keep full json objects in memory if no longer needed.

 include/openvswitch/json.h |   9 ++-
 lib/json.c                 |  34 ++++++++++++
 ovsdb/ovsdb-tool.c         |  10 ++--
 ovsdb/raft-private.c       | 111 +++++++++++++++++++++++++++++++++----
 ovsdb/raft-private.h       |  12 +++-
 ovsdb/raft.c               |  94 +++++++++++++++++--------------
 ovsdb/raft.h               |   3 +-
 ovsdb/storage.c            |   4 +-
 8 files changed, 211 insertions(+), 66 deletions(-)

-- 
2.31.1