Don't list old metric names?

[mzealey]

Is there a way to filter the metric name list so that I can exclude metrics that have not been inserted in the past few days? I can see in the RU wiki page there is detail about the old index_tree table where you could set Deleted = 1 but can't seem to find any documentation about how to do this currently?

[deniszh]

@mzealey : if your Clickhouse support deletion you can try same trick, but with DELETE

ALTER TABLE graphite_index DELETE 
WHERE (Path LIKE 'PREFIX.%')
GROUP BY Path
HAVING max(Version) < toUInt32(toDateTime(today() - 7))

But I'm not sure if DELETE WHERE supports GROUP BY ... HAVING clause.

[mzealey]

I imagine sometihng like this would work:

ALTER TABLE graphite_index
DELETE WHERE Path in (
  SELECT Path
  FROM graphite_index
  WHERE (Path LIKE 'PREFIX.%')
  GROUP BY Path
  HAVING max(Version) < toUInt32(toDateTime(today() - 7))
)

But there are also partial and reversed paths etc as well; do they not need deleting somehow?

[deniszh]

Yep, then SELECT should bit more complex. Reversed is easy, not sure about partial, though.

[Felixoid]

It looks related to #64

[bzed]

Also I think you want to select the Paths from graphite_index first, then remove the data from the graphite table and then tidy the graphite_index table? Does that make sense?

[spoofedpacket]

Could the 'delete' column features in recent clickhouse versions be leveraged for this?
https://altinity.com/blog/clickhouse-replacingmergetree-explained-the-good-the-bad-and-the-ugly

We are using the ALTER TABLE method described above for some time now, while it works as expected it puts significant load on clickhouse so it would be great to have a lightweight alternative.

[Felixoid]

https://clickhouse.com/docs/en/sql-reference/statements/delete exists for quite a long.

[mzealey]

Yeah I'd use the lightweight deletes as above. Probably can just change the 'alter table x delete' bit to 'delete from x'.