olap

In Big Query there is a function array_concat_agg that aggregates array fields by concatenating the arrays. In Snowflake there is a flatten function that can unnest nested arrays into single array. I am looking for similar functionality in duckdb.

select flatten([[1, 2], [2, 3], [4, 5]] would return [1, 2, 2, 3, 4, 5]
I would also need a distinct option:
`select flatten(DISTINCT [[1, 2],

Search before asking

• I had searched in the issues and found no similar issues.

Description

As title.

In BE, there are some many Substitute stringstream, we can replace them with fmt/format

Solution

No response

Are you willing to submit PR?

• Yes I am willing to submit a PR

Summary

./target/debug/databend-query 

... ... 
2022-06-19T03:31:37.041051Z  INFO databend_query: Listening for ClickHouse compatibility native protocol: 127.0.0.1:9000, Usage: clickhouse-client --host 127.0.0.1 --port 9000
2022-06-19T03:31:37.042913Z  INFO databend_query: Listening for ClickHouse compatibility http protocol: 127.0.0.1:8124, Usage:  echo 'create table test(foo str

Use case:

Get the total duration over many events. Something like select sum(age(ended, started)) from myevents or select sum(ended - started) from myevents - depending on crate/crate#12479

See https://github.com/crate/crate/blob/dc3ce297b1597d482949a2e57479890feb3adbf4/server/src/main/java/io/crate/execution/engine/aggregation/impl/SumAggregation.java#L67

Enhancement

Currently, delta_writer_commit span runs in tablet_writer_add_chunk rpc handler, which is in bthread environment, and aync_delta_writer is used, so thread may get switched, as a result delta_writer_commit didn't catch load_channel span automatically, so we need to set delta_writer_commit span's parent explicitly.

Hey everyone!

mapd-core-cpu is already available on conda-forge (https://anaconda.org/conda-forge/omniscidb-cpu)

now we should add some instructions on the documentation.

at this moment it is available for linux and osx.

some additional information about the configuration:

1. for now, always install omniscidb-cpu inside a conda environment (also it is a good practice), eg:

Describe the bug
@Ted-Jiang found and fixed a bug (apache/arrow-datafusion#2729) related to the fact an optimizer function rewrite_expression did not handle Expr::InList correctly

During review @andygrove and I noticed there were likely some other Expr variants that suffered from the same issue: apache/arrow-datafusion#2729 (comment)

Is there an existing issue for the same feature request?

• I have checked the existing issues.

Is your feature request related to a problem?

Several showcase SQL requires the support of this function:


select DATE_FORMAT(b.measurement_time,'%Y-%m-%d') 

select DATE_FORMAT(FROM_UNIXTIME(tm.create_time), %Y%m%d)

Describe the feature you'd like

Search before asking

• I had searched in the issues and found no similar optimization requirement.

Description

Translate the README.md and README.en-US.md into English

Are you willing to submit a PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's [Code of Conduct](h

If we find distinct value statistics is very small compared with row counts, we can use RLE encoding when building RowSets.

https://github.com/risinglightdb/risinglight/blob/65372ee4da36bada718a6ab00cdba865ba554e5e/src/storage/secondary/compactor.rs#L93-L96