zX41ZdbW

46 ms·

721.
by zX41ZdbW 4y ago
ClickHouse is almost ubiquitous for web analytics services. For example, here is news from today about Splitbee: https://news.ycombinator.com/item?id=33334104 No surprise it is using ClickHouse: https://splitbee.
722.
The fastest command-line tools for querying large JSON datasets(github.com)
6 points by zX41ZdbW 4y ago|0 comments
723.
by zX41ZdbW 4y ago
While reading the article, I found that they are rediscovering the tricks, already well-known for ClickHouse: > The biggest mistake I made was that I kept the UPDATEs in our code (we update the previous pageview with the duration, remove
724.
The world’s fastest tool for querying JSON files(clickhouse.com)
3 points by zX41ZdbW 4y ago|0 comments
725.
by zX41ZdbW 4y ago
Why do you think so? The query performance of ClickHouse will be well above any of the listed engines. The versatility of the query language and support for data formats are also way ahead.
726.
Wrapping a Serverless ClickHouse Pt.1(blog.qryn.dev)
3 points by zX41ZdbW 4y ago|2 comments
727.
by zX41ZdbW 4y ago
Arctype is well-polished and feels very natural with ClickHouse, there are not many SQL UIs like this. Frankly speaking, there are not many JavaScript applications that don't look like garbage. At least Arctype is not slow.
728.
by zX41ZdbW 4y ago
> It will be interesting to watch this unfold from a code licensing perspective. Will Clickhouse Inc. move to a more restrictive license to block all these other ClickHouse services? I don't see it as a reasonable move.
729.
by zX41ZdbW 4y ago
ClickHouse supports ad-hoc analytics, real-time reporting, and time series workloads at the same time. It is perfectly suited for user-facing analytics services. It supports low-latency (<100ms) queries for real-time analytics as well as
730.
by zX41ZdbW 4y ago
ClickHouse Cloud provides port 443 as well as 8443. You can insert one row at a time, it's perfectly ok with "async_insert=1".
731.
by zX41ZdbW 4y ago
> Does anyone know how much of the Clickhouse team (or ownership) is still located in Russia? Zero. No employees in Russia, no ownership from Russia, no influence from Russia.
732.
by zX41ZdbW 4y ago
A single INSERT takes around 0.01 write units.
733.
by zX41ZdbW 4y ago
No, write unit is not a single INSERT. A single INSERT will take around 0.01 write units.
734.
by zX41ZdbW 4y ago
One write unit is around 100..200 INSERT queries. If you are doing INSERT in batches with one million rows, it will give SELECT formatReadableQuantity(1000000 * 100 / 0.0125) 8.00 billion inserted rows per dollar. Pre
735.
by zX41ZdbW 4y ago
It is related to the "max_threads" setting of ClickHouse, and by default, it is the number of physical CPU cores, which is twice lower as the number of vCPUs. For example, the c6a.4xlarge instance type in AWS has 16 vCPUs, 8 cores
736.
by zX41ZdbW 4y ago
There is a good reference to the available benchmarks for analytical databases: https://github.com/ClickHouse/ClickBench#similar-projects
737.
by zX41ZdbW 4y ago
ClickHouse can push cold data directly to S3, so S3 will be used as cold storage and the local filesystem as hot storage. Another approach is to store all in S3 with local caching, it is much more easy and somewhat more efficient. ClickHous
738.
by zX41ZdbW 4y ago
I have (an extremely boring, but quite hands-on) video about various ways of ClickHouse optimizations on top of external storage: https://www.youtube.com/watch?v=rK2BsaaaOCA (starting from around 40:00).
739.
by zX41ZdbW 4y ago
It is very easy with ClickHouse. All you need is: SELECT ... FROM postgresql(...) FORMAT Parquet And you can run this query without installing ClickHouse, using the clickhouse-local command-line tool. It can be downloaded simply as: curl h
740.
by zX41ZdbW 4y ago
What is surprising: if you query MySQL from ClickHouse, the queries work faster despite the fact that the data is simply read from MySQL. And two more use-cases: - you can create a table in ClickHouse pointing to multiple MySQL servers for
741.
by zX41ZdbW 4y ago
Similar features available for MySQL, MongoDB and SQLite.
742.
by zX41ZdbW 4y ago
Yes, ClickHouse can query Postgres for maybe two years already. https://clickhouse.com/docs/en/integrations/postgresql/postg... You can connect to Postgres using a table function: SELECT ... FROM postgre
743.
by zX41ZdbW 4y ago
You are talking about the old tcmalloc from 2006 that should never be used anymore. There is also a new tcmaloc: https://github.com/google/tcmalloc/ If you are in doubt, you should simply use what ClickHouse is us
744.
by zX41ZdbW 4y ago
Here is an overview of the usage of the shuffle instruction to speed up decompression in ClickHouse: https://habr.com/ru/company/yandex/blog/457612/
745.
by zX41ZdbW 4y ago
How does it compare with ClickHouse?
746.
by zX41ZdbW 4y ago
We are using this technique in ClickHouse to make performance tests more stable. ClickHouse automatically collects CPU performance counters on a per-query basis, and we see the changes on a diagram of iTLB misses. Although the average perfo
747.
by zX41ZdbW 4y ago
DuckDB is obviously faster than SQLite on analytical queries, from 10 to 11 000 times on a benchmark [1]. But in comparison to SQLite, DuckDB cannot run all the queries due to worse memory management. It cannot run 12 out of 43 queries. [1]
748.
by zX41ZdbW 4y ago
It improves string comparison and sorting in ClickHouse by 15%: https://github.com/ClickHouse/ClickHouse/pull/38093
749.
by zX41ZdbW 4y ago
camelCase - native functions SQL_STYLE_CASE - compatible functions
750.
by zX41ZdbW 4y ago
Yes (but only scripted, without compilation): `grep` | 0.03 | 0.03 | `grep` baseline; optimized sets `LC_ALL=C` `wc -w` | 0.18 | 0.25 | `wc` baseline; optimized sets `LC_ALL=C` SQL | 0.26 | |

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