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Ten years of ClickHouse in open source

clickhouse.com

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Re: Ten years of ClickHouse in open source

#11
I discovered ClickHouse around 2017-18 and built a PoC to replace Elasticsearch: 5x better storage and qps, in a couple of weeks.

Managers rejected it because it wasn't well known and was seen as "some database made by Russians."

On a personal level, it's quite sad to have seen that train coming so early and not been able to get on board.

Re: Ten years of ClickHouse in open source

#12
> You can open a pull request as an experiment, without aiming for it to be merged - it will be tested with the same level of scrutiny as production releases. Found a new memory allocator, a new compression library, a new hash table, a data format, or a sorting algorithm? - bring it to ClickHouse, and it will expose it inside-out

Wow

Re: Ten years of ClickHouse in open source

#15
post #11

I discovered ClickHouse around 2017-18 and built a PoC to replace Elasticsearch: 5x better storage and qps, in a couple of weeks. Managers rejected it because it wasn't well known and was seen as "some database made by Russians." On a personal level, it's quite sad to have seen that train coming so early and not been able to get on board.

Same we are also stuck with ES wish could migrate to clickhouse but not able to do so because of the legacy load.

Re: Ten years of ClickHouse in open source

#16

ClickHouse recently has been a breath of fresh air compared to using timescaledb for a long time. Although psql is the greatest there is and I really enjoyed the fact that I could rely on a single database system to run everything, when it came to migration maintenance and deployment it's really a pain and it also feels like development on timescaledb is a bit wishy washy with all the structural changes from version…

I was using TimescaleDB some very long time ago, things have changed quite a lot since (it's now even named differently).

In my current setup I was thinking on doing both: upgrading postgresql to timescaledb (to archive old data etc.), and to deploy ClickHouse in parallel. I'm still considering whether to go big on PeerDB to get ClickHouse mirror or just deploy it separately without additional fragility layer.

Would you not recommend using timescaledb at all? I definitely want to avoid alpha-quality software pain, since PostgreSQL is one of the most rock-solid parts of the stack at the moment.

Re: Ten years of ClickHouse in open source

#17

> You can open a pull request as an experiment, without aiming for it to be merged - it will be tested with the same level of scrutiny as production releases. Found a new memory allocator, a new compression library, a new hash table, a data format, or a sorting algorithm? - bring it to ClickHouse, and it will expose it inside-out Wow

ClickHouse dev here, but this is true. ClickHouse contributed finding several bugs on our third-party libs (jemalloc, librdkafka for 100%, there much more, but I only worked on these), in linux kernel and basically everywhere. We have very rigorous fuzzers (yes, multiple fuzzers on multiple levels), running tests in insane number of configurations. I think the last number I heard a year ago is around 400 hours for a complete CI run for a single commit (not PR, but commit). So yeah, pretty insane, in the good way.

Re: Ten years of ClickHouse in open source

#19
post #16

ClickHouse recently has been a breath of fresh air compared to using timescaledb for a long time. Although psql is the greatest there is and I really enjoyed the fact that I could rely on a single database system to run everything, when it came to migration maintenance and deployment it's really a pain and it also feels like development on timescaledb is a bit wishy washy with all the structural changes from version…

I was using TimescaleDB some very long time ago, things have changed quite a lot since (it's now even named differently). In my current setup I was thinking on doing both: upgrading postgresql to timescaledb (to archive old data etc.), and to deploy ClickHouse in parallel. I'm still considering whether to go big on PeerDB to get ClickHouse mirror or just deploy it separately without additional fragility layer. Would…

Worked on peerdb. If you're able to batch changes on your end & push to both postgres & clickhouse, do that. Only move to peerdb when you know you need cdc

Re: Ten years of ClickHouse in open source

#20
The query speed deserves the praise, but the JSON ingestion path has quiet footguns nobody mentions here. Every numeric column comes back as a string over JSONEachRow, so a forgotten Number() cast silently turns arithmetic into string concatenation, and with input_format_skip_unknown_fields enabled a single typo in a column name drops that field with no error at all. Worth wiring an assertion that inserts a row and reads it back into CI before trusting the dashboards.
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