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Questions tagged [questdb]

QuestDB is a high-performance, open-source SQL database used in financial services, IoT, machine learning, DevOps and observability.

QuestDB is an open-source SQL database for applications in financial services, IoT, machine learning, DevOps and observability. Questions with this tag should be about compatibility with the main interfaces:

  • queries and ingestion using PostgreSQL wire protocol
  • ingestion over InfluxDB Line Protocol
  • REST API for queries, bulk imports, and exports

Questions with this tag may also focus on SQL syntax and usage for time-oriented language features. For questions with language compatibility, add these tags where appropriate (e.g. [python-2.7] or [python-3.x]).

215 questions
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What is timeseries data cardinality?

I've seen few places which give definition of time-series cardinality similar to: Assume you have 1000 IoT devices in 20 locations, they're running one of 5 firmware versions, and report input from 5 types of sensor per device. The cardinality of…
Alex des Pelagos
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How to delete a few rows via SQL in QuestDB?

is there a way to delete a view rows matching a query in QuestDB? I can't find any statement allowing me that. This would be the best option: delete from mytable where columnvalue==2; Thanks!
mojovski
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Does QuestDB supports Foreign key, Primary key, references?

I wonder how db schema design would look, because at first glance I need bunch sql relation features, that are not available out of box in QuestDB.
samO0
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Exporting data from mysql RDS for import into questDb

I've got a big table (~500m rows) in mysql RDS and I need to export specific columns from it to csv, to enable import into questDb. Normally I'd use into outfile but this isn't supported on RDS as there is no access to the file system. I've tried…
Sam Shiles
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2 answers

Does QuestDB have EXPLAIN

Postgres has syntax to show the query plan for a SQL statement: https://www.postgresql.org/docs/9.4/using-explain.html Does QuestDB have something equivalent so that I can see the query plan that would result from my SQL before actually executing…
marregui
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1 answer

When working with QuestDB, are symbol columns good for performance for huge amounts of rows each?

When working with regular SQL databases, indexes are useful for fetching a few rows, but not so useful when you are fetching a large amount of data from a table. For example, imagine you have a table with stock valuations of 10 stocks over…
Giovanni Bonetti
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How do I compute moving averages on QuestDB?

I'm using the database QuestDB, and trying to compute moving averages with some market data Is this something that is already available out of the box (like in Influxdb or kdb+), or is there a way around it?
terminusfoundation 94
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How do you get prometheus metrics from QuestDB

I see that there's support for prometheus metrics added to QuestDB in https://github.com/questdb/questdb/pull/905 How do I get metrics or gauges out of QuestDB into prom? If I search for metrics on the configuration page it shows something for…
BurningFlan
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What does "max txn-txn-inflight limit reached" in QuestDb, and how to I avoid it?

I occasionally get "txn-txn-inflight limit reached [txn=251584, min=240384]" on servers when attempting to read data from (embedded) QuestDb. It self corrects after some time (minutes). What does it mean and what can I do to avoid it?
Jon
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1 answer

How to decide what table partitioning strategy to use in QuestDB?

I am designing a table of metrics in QuestDB. There will be few million rows per day they spread evenly thought the day. The rows are around 200 bytes, all numbers and timestamp. The data reading will span across multiple days usually, up to a year…
Nick The Greek
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How can I prevent accidental deletion of records in QuestDB?

I want to expose a QuestDB instance publicly with the web interface so that users and visitors can make queries against the data. How can I make sure data won't be deleted from this dataset? Is there a way to prevent malicious queries?
funnymay
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Is there any unique key constraint on timestamps in QuestDB?

I'm sending some data to QuestDB and I'm curious if two records incoming that have the same timestamp will cause an issue / conflicts. Not even duplicate values, but values from different devices with the same timestamp. Any there any unique key…
Doncarleone512
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2 answers

How do I create a new database in Questdb?

I would like to be able to separate multiple types of data in Questdb but it looks like I can't perform something like CREATE DATABASE new_db; But I get table expected error. Is is possible outside of SQL to add a new database?
Doncarleone512
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How to import InfluxDB tables into QuestDB?

I am trying to move data from InfluxDB to QuestDB, I was able to export my tables as JSON by following: https://stackoverflow.com/a/27913640/1267728 How do I now import these JSON files into QuestDB?
Awalias
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How do I import single-line CSV into QuestDB?

I'm trying to import a table into QuestDB via the /imp REST endpoint. The file contains a single row one with no column row: a,10.5,True I'm trying to import it with cURL: curl -v -F data=@input.csv 'http://localhost:9000/imp?name=my_table' but…
Andrei Pechkurov
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