zX41ZdbW

59 ms·

811.
by zX41ZdbW 5y ago
Thank you! Looking forward for a blog post. We need more references for comparison to optimize ClickHouse performance.
812.
by zX41ZdbW 5y ago
> Disclaimer: I work for a competitor What competitor btw? I tried to open a link from your profile but it does not work.
813.
by zX41ZdbW 5y ago
There are many independent comparisons of ClickHouse vs TimescaleDB: By Splitbee: https://github.com/ClickHouse/ClickHouse/issues/22398#issuec... By GitLab: https://github.com/ClickHouse/
814.
by zX41ZdbW 5y ago
Thank you! This is an important milestone for ClickHouse and will benefit the entire ecosystem.
815.
ClickHouse, Inc.(github.com)
519 points by zX41ZdbW 5y ago|159 comments
816.
by zX41ZdbW 5y ago
Cheburashka is on the photo, wearing ClickHouse T-shirt.
817.
Testing the Performance of ClickHouse(clickhouse.tech)
5 points by zX41ZdbW 5y ago|1 comments
818.
by zX41ZdbW 5y ago
In ClickHouse there is 1.6 times performance improvement after simply adding __restrict in aggregate functions: https://github.com/ClickHouse/ClickHouse/pull/19946#issuecom...
819.
by zX41ZdbW 5y ago
I've created a page to test monospace fonts in browser: https://alexey-milovidov.github.io/font-selector/ This is intended mostly for my own use case: desktop workstation, light theme, C++ development environment.
820.
by zX41ZdbW 5y ago
This is also fixed in ClickHouse - you can set and reuse aliases in any expressions in the query.
821.
by zX41ZdbW 5y ago
This is how it is done in ClickHouse. It has Nullable(T) type. The functions of non-Nullable types will return non-Nullable types (except some specific functions). https://clickhouse.tech/docs/en/sql-reference&#x2F
822.
A journey to io_uring, AIO and modern storage devices(clickhouse.tech)
3 points by zX41ZdbW 5y ago|0 comments
823.
by zX41ZdbW 5y ago
ClickHouse has support for block range indexes as well. If you want to check open-source implementations - this is probably the best place to do it.
824.
by zX41ZdbW 5y ago
ClickHouse has both variants: primary and seconday indexes. Primary key is range index - to quickly locate records. Secondary indexes are data skipping indexes - to quickly skip blocks of data.
825.
by zX41ZdbW 5y ago
What are the largest datasets in Splitgraph? Can I list the datasets sorted by size? We have the need for large public datasets for testing ClickHouse: https://clickhouse.tech/docs/en/getting-started/example-d
826.
The Tests Are Passing, Why Would I Read the Diff Again?(clickhouse.tech)
1 points by zX41ZdbW 6y ago|0 comments
827.
by zX41ZdbW 6y ago
Testing performance of memcpy should be more exhaustive than just running on single CPU: https://github.com/ClickHouse/ClickHouse/issues/18583#issuec...
828.
by zX41ZdbW 6y ago
Actually in their example, no data is processed. The query compiled to a loop over natural numbers that was optimized by the compiler: uint64_t x = 0; for (uint64_t i = 0; i < 1000000000000; ++i) x += i; print x; This loop is complet
829.
by zX41ZdbW 6y ago
The similar list from ClickHouse repository: https://github.com/ClickHouse/ClickHouse/blob/master/base/ha...
830.
by zX41ZdbW 6y ago
Secondary indexes are supported by ClickHouse. https://clickhouse.tech/docs/en/engines/table-engines/merget... They are not like indexes for point lookups, but also sparse. Actually they are the best you
831.
by zX41ZdbW 6y ago
ClickHouse supports transactional (ACID) properties for INSERT queries. It can also replicate data across geographically distributed locations with automatic support for consistency, failover and recovery. Quorum writes are supported as wel
832.
by zX41ZdbW 6y ago
ClickHouse has support for multidimensional arrays with arbitrary types and number of dimensions. They are stored in tables in efficient column-oriented format.
833.
by zX41ZdbW 6y ago
ClickHouse has support for multidimensional arrays.
834.
by zX41ZdbW 6y ago
I'm trying to evaluate Coderrect (first without GitHub Actions), but most likely missed something as it found zero races: https://github.com/coderrect-inc/coderrect-github-action/iss... Could you please help
835.
by zX41ZdbW 6y ago
It is very interesting that compression libraries from Yann Collet outperform their Google counterparts by all means: lz4 >> snappy zstd >> brotli
836.
by zX41ZdbW 6y ago
Using LZ4 can easily improve performance even if all data reside in memory. This is the case in ClickHouse: if data is compressed, we decompress it in blocks that fit in CPU cache and then perform data processing inside cache; if data is un
837.
by zX41ZdbW 6y ago
It is possible to make LZ4 decompression even faster, here's how: https://habr.com/en/company/yandex/blog/457612/
838.
by zX41ZdbW 6y ago
You can obtain this data for all existing repositories by one request in one second: https://gh-api.clickhouse.tech/play?user=play#U0VMRUNUCiAgIC...
839.
by zX41ZdbW 6y ago
Also take a look at the more technical overview of the Octoverse: https://gh.clickhouse.tech/explorer/ It is like interactive notebook when you can edit and run your own queries on the metadata from GitHub.
840.
State of the Octoverse(octoverse.github.com)
8 points by zX41ZdbW 6y ago|3 comments

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