QuestDB is a timeseries database optimized to append data.
For best performance, design your application to avoid having to frequently edit existing records.
UPDATE statement is available in QuestDB
since version 6.4,
DELETE is also planned to be included in upcoming releases.
However, they are intended for correcting data that was inserted incorrectly
or should have never been inserted in the first place (for example as part
of data administration tasks).
These are three alternatives to
DELETE you may consider:
Append newest state: Insert a newer state to replace an older one: This has the added advantage that you can query back in time to a previous state. It is also the basis of organizing data for bi-temporality.
Replace a table: Create a new table with the new data you need, drop the old one and rename.
Delete by dropping partitions: Create your timeseries tables with partitions, then delete the ones you no longer need.
#Append newest state
#Using the timestamp field
Here's a worked example using the timestamp column:
We join the latest timestamp of an order id against the rest of the data to obtain full details.
This results in the latest state for each order:
|timestamp ts||id symbol||status symbol|
#Using dedicated fields
If timestamps don't work for you here, you can also use an extra integer column
version, an extra boolean
deleted column or similar.
Another alternative is to:
- Select only the data you want from an existing table into a new temporary one.
- Drop the original table.
- Rename the temporary table to the original table's name.
#Delete by Dropping Partitions
When you create tables with a timestamp, you may organise them into
partitions using the
CREATE TABLE .. PARTITION BY
You may then use the
ALTER TABLE DROP PARTITION
SQL statement to drop partitions you no longer need.