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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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How to add / alter symbol index capacilty after table is created?

I have a table in QuestDB which I created with symbol columns. I added index after that as per documentations as ALTER TABLE tbl ALTER COLUMN instrument ADD INDEX; Now I realize I'd like to specify index capacity to try turn the performance. I…
allnau
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How to use ILP data types with QuestDB data types?

I use QuestDb with Influx Line Protocol. When I send new metric QuestDB automatically creates a table and for all my numbers it uses DOUBLE type. Also it can create SYMBOL for Tags and String for other string fields in the message and LONG for…
Nick The Greek
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Bit Math for QuestDB

Does the database QuestDB support BitMath, i.e. the ability to manipulate individual bits? I tried using field & 1 == true but I get the following in return: unexpected character.
terminusfoundation 94
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Is it possible to use psycopg2 for prepared statements?

I'm comparing some of the features of Postgres clients for compatibility and I'm having difficulty getting prepared statements to work in psychopg2. The Node.js pg package allows me to do the following where providing a name (insert-values) prepares…
Brian Smith
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How to check if an existing table has a designated timestamp?

Once I have an existing table in QuestDB, is there any way to check if the table has a designated timestamp and if yes, which column is it?
Newskooler
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How can I see a service's logs when running it from Docker?

I'm running questdb in docker with this command: docker run -p 9000:9000 -p 8812:8812 -d questdb/questdb How can I check the log output of this service? It's not really convenient for me to write the database logs to disk, but I would like to check…
djbobo
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Docker env variables in QuestDB?

I am using docker and ingestion protocol ILP to send data to questdb. I tried to export using this page env variables: https://questdb.io/docs/reference/configuration/#influxdb-line-protocol-tcp The export commands to not work on docker - what are…
terminusfoundation 94
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Is it possible to perform a regex match on SYMBOL types in QuestDB?

I am trying to perform a regex match on a symbol column: SELECT * FROM my_table WHERE ~=(col_name, 'some.*') This is not working for me, but I can't tell from the error if this is because I'm using unsupported match operators (.*), if the…
Doncarleone512
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How do I calculate spikes in data over the last x amount of minutes in QuestDB

I have a table CPU with some metrics coming in over Influx line protocol, how can I run a query that tells me if data has exceeded a certain threshold in the last x minutes, I am trying to do something like: select usage_system, timestamp from…
djbobo
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Can I copy data table folders in QuestDb to another instance?

I am running QuestDb on production server which constantly writes data to a table, 24x7. The table is daily partitioned. I want to copy data to another instance and update it there incrementally since the old days data never changes. Sometimes the…
allnau
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How do I get the top-5 devices by value from a table of IoT sensors in QuestDB?

I have a table that looks like the…
djbobo
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Warnings about javac when building QuestDB from source

I'm trying to build QuestDB from source on a newly setup machine and I get warnings about javac: [INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ questdb --- [INFO] Changes detected - recompiling the module! [INFO] Compiling 1292…
djbobo
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How can I calculate how long ago a boolean record occurred in QuestDB?

I have a table iot that has some sensor data, one of the columns is booleans as indicators that some event occurred, how can I calculate how long ago the most recent true value happened in a column using SQL? The example data set looks something…
djbobo
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Cannot insert to QuestDb using Influx Line Protocol

I am trying to insert data to QuestDb using Influx Line Protocol but cannot see anything when I query the table. My code is very simple, ILP line is taken from the QuestDb ILP examples Poco::Net::SocketAddress socket_address{ "127.0.0.1", 9009…
allnau
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How to model a table to save many metrics for same timestamp in QuestDb?

I have zillion lot of sensors which tick every min with some floating point data and I want to use to save the data in QuestDb. I see two options: Options 1 is to create a wide table with zillion of columns and have one row per each minute | Time |…
Nick The Greek
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