Per-database compaction daemon settings have no effect

[lewmelvinwork]

I'm using couchdb 2.0.0 on RHEL 7.2 and I'm looking to configure automatic compaction of _global_changes but I can't seem to get it to work. I've checked the file size and data size of the _global_changes database so I know the criteria I've specified have been met. I don't get an error upon couchdb startup, but nothing happens. When I tried setting a _default compaction rule, then compaction does happen for all databases including _global_changes.

Expected Behavior

Compaction of _global_changes should be triggered when the check_interval passes and the file and data sizes meet the parameters of the compaction configuration. In my testing, it doesn't get triggered.

Current Behavior

Nothing happens. There is no error in the log for the configuration, yet the check_interval passes and no compaction event occurs.

Possible Solution

I contacted the CouchDB Users email list and Adam replied with the following:

Hiya Melvin, this looks like a bug. I think what’s happening is the compaction daemon is walking the list of database shards on the node and comparing those names directly against the keys in that config block. The shard files have internal names like

shards/00000000-1fffffff/_global_changes.1512750761

If you want to test this out you could look for the full path to one of your _global_changes shards and supply that as the key instead of just “_global_changes”. Repeating the config entry for every one of the shards could also be a workaround for you until we get this patched. Can you file an issue for it at https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_apache_couchdb_issues-3F&d=DwIFaQ&c=nulvIAQnC0yOOjC0e0NVa8TOcyq9jNhjZ156R-JJU10&r=jjIKqwApUzKCDY-o1Ex3afd4bksosuJsda_NnZShUUM&m=XHjiBSrSt89_WhJ4-9-2UpcbGcs9zvxIpJN-QXPCNBI&s=dRWvHDgKxwCB7lPHOIDib7jmUy9wVGLuDcG0j0N3R7s&e=

By the way, releases prior to 1.7.1 and 2.1.1 have a fairly serious security vulnerability, it’d be good if you could upgrade. Cheers,

Adam

Steps to Reproduce (for bugs)

This is what I have in local.ini that does not work:
[compactions]
_global_changes = [{db_fragmentation, "70%"}]

Putting this into local.ini does work, but I don't want to compact all databases:
[compactions]
_default = [{db_fragmentation, "70%"}]

For the purposes of my testing, I've also added:
[compaction_daemon]
check_interval = 30

Context

_global_changes grows a lot and fills my filesystem. Enabling compaction will keep this disk growth under control.

Your Environment

• Version used: CouchDB 2.0.0
• Browser Name and version:
• Operating System and version (desktop or mobile): RHEL Linux 7.2
• Link to your project: