Re: Scaling issue with Solr

[Shawn Heisey <ap...@elyograg.org>]

On 12/27/2017 3:15 PM, Damien Kamerman wrote:
> You seem to have the soft and hard commits the wrong way around. Hard
> commit is more expensive.

That is only the case if the hard commit has openSearcher set to true.

It is strongly recommended for ALL users to have openSearcher set to
false on autoCommit, and that autoCommit should be enabled.  The example
configs in recent versions have it enabled, set to 15 seconds, with
openSearcher set to false.  I personally would set it to 60-120 seconds,
just because I would like the server to be doing less work.  My servers
are not usually index-heavy, though -- so my restarts are still fast
even with a 60 second autoCommit.

The default for openSearcher is true, so I think that if autoCommit
doesn't specify it, then it is enabled.  The default for autoCommit
should likely change in 8.0, though I do not think that the default for
the commit operation itself should change.

In some situations, soft commits are just as expensive as hard commits
when openSearcher=true.  The really expensive part of a commit is
opening a new searcher, which soft commit does, so in the recommended
config, autoCommit will be much faster than autoSoftCommit.

Thanks,
Shawn