Server shard map not reloaded on restart

[otoolep]

cc @benbjohnson

My testing shows this to be true. It's loaded when a shard is created, but not when the metastore is re-loaded.

[pauldix]

@otoolep can you give more detail on this? I'm not quite sure what this means.

[otoolep]

Specifically, when a shard group is created, this code is executed:

https://github.com/influxdb/influxdb/blob/master/server.go#L1024

which updates:

https://github.com/influxdb/influxdb/blob/master/server.go#L73

but when this function is executed:

https://github.com/influxdb/influxdb/blob/master/server.go#L271

the map is not updated. I hit this during stats work, and planned to fix it as I continued my work on stats.

[otoolep]

This is my hypothesis. All I have actually seen is that the map goes to nil after a restart and reload from metastore.

[pauldix]

So wait, does that mean after restart none of the shards are there?

On Fri, Mar 20, 2015 at 4:16 PM, otoolep [email protected] wrote:

This is my hypothesis. All I have actually seen is that the map goes to []
after a restart and reload from metastore.

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#2012 (comment).

[pauldix]

That's what I'm more interested in. What happens and what the severity of
the issue is.

On Fri, Mar 20, 2015 at 4:18 PM, Paul Dix [email protected] wrote:

So wait, does that mean after restart none of the shards are there?

On Fri, Mar 20, 2015 at 4:16 PM, otoolep [email protected] wrote:

This is my hypothesis. All I have actually seen is that the map goes to
[] after a restart and reload from metastore.

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Reply to this email directly or view it on GitHub
#2012 (comment).

[otoolep]

Queries continue to work fine after a restart, so it's not that serious. The system uses a different path when it comes to finding shards for reads and writes, this map is not actually that critical. I believe it's just for the purposes of optimization (some early idea we had), and the authoritative data is in the database and retention policy objects. In fact I was considering removing it since it seems like cruft. @benbjohnson might know better of course.

[otoolep]

Fixed.