[clickhouse] Use chrono::UTC for distributed_ddl_queue endpoint

[karencfv]

Modified the SQL query to set the date/time format to one we can parse.

$ curl http://[::1]:8888/distributed-ddl-queue | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  1993  100  1993    0     0   4203      0 --:--:-- --:--:-- --:--:--  4213
[
  {
    "entry": "query-0000000001",
    "entry_version": 5,
    "initiator_host": "ixchel",
    "initiator_port": 22001,
    "cluster": "oximeter_cluster",
    "query": "CREATE DATABASE IF NOT EXISTS db1 UUID '701a3dd3-10f0-4f5d-b5b2-0ad11bcf2b17' ON CLUSTER oximeter_cluster",
    "settings": {
      "load_balancing": "random"
    },
    "query_create_time": "2024-11-01T03:17:08Z",
    "host": "::1",
    "port": 22001,
    "status": "Finished",
    "exception_code": 0,
    "exception_text": "",
    "query_finish_time": "2024-11-01T03:17:08Z",
    "query_duration_ms": 3
  },

[bnaecker]

You can add query-specific settings by tacking them on at the end: https://clickhouse.com/docs/en/sql-reference/statements/select#syntax. So you would do SELECT … SETTINGS date_time_output_format = ‘iso’.

[karencfv]

You can add query-specific settings by tacking them on at the end: https://clickhouse.com/docs/en/sql-reference/statements/select#syntax. So you would do SELECT … SETTINGS date_time_output_format = ‘iso’.

Nice! Thanks @bnaecker, I've made the modifications

[bnaecker]

Looks good! One question about parsing, but otherwise good to go. Thanks!

[bnaecker]

Looks like this is a UInt64, is it worth parsing into a stronger type during deserialization? Something like a Duration, or at least u64?

[karencfv]

It's a string with a number in it :( I initially had it as a u64 and it didn't parse, but let me try with Duration!

[bnaecker]

Ah, this is because we're asking for JSON, and by default ClickHouse quotes 64-bit numbers. That causes serde to think it's a string, because it's written like "1", rather than just 1. You can set the output_format_json_quote_64bit_integers setting to ask it not to that.

[karencfv]

Looks like Duration doesn't accept strings either :(

[bnaecker]

See my earlier comment. You can ask CH not to quote big integers, so that serde can parse it just fine.

[karencfv]

ugh sorry, GitHub hid that comment from me, I see it now thanks!

[bnaecker]

No worries, I figured :) Just didn't want you to lose track of it. I think that will work, but it's honestly up to you if you want to apply it. I don't have context for what this all will be used for!

[karencfv]

That worked, thanks! It's definitely better with strong types. Wasn't able to get Duration to parse but at least it's u64 now. We're going to use this endpoint (and others) for long term monitoring and debugging of the ClickHouse cluster.