15,304 questions
2
votes
1
answer
87
views
How to improve query performance on large time-series container in GridDB Cloud?
I’m using GridDB Cloud (Free Tier) with Python to store time-series IoT data.
My container currently has around 10 million rows, and it continues to grow daily.
Schema:
device_id STRING,
created_at ...
- 67
1
vote
1
answer
60
views
Interpolate data using indicator in time series
I am trying to interpolate data in a time series where I have data for the variable every four years and an annual data of an indicator variable.
My goal is that the movement of the indicator is ...
- 21
0
votes
1
answer
36
views
How to configure roll function for sliding window on irregular stock data?
I am working with irregular minute-level stock data in DolphinDB and need to implement a specific rolling calculation using the roll function which is new in version 3.00.4.
I have a custom ...
- 15
0
votes
1
answer
32
views
Upsert! Operation Throws "A table can't contain duplicate column names" Error
I have a base table A and a result table B in DolphinDB. Table B was initially empty and is used to store calculated results based on table A. When trying to insert the calculated results into table B,...
- 1
0
votes
1
answer
83
views
"top" function unrecognized in grouped quantile calculation + efficient grouped top 5% statistics
I need to process a large L2 market data table (≈30 million rows) in DolphinDB and calculate statistics for the top 5% of records per group. However, I’m stuck on a syntax error with the top function ...
0
votes
0
answers
13
views
Forecasting with VAR models after differencing some time series [migrated]
i have data from 85 participants who answered 6 items for 82 consecutive days. In other words: I have 6 time series per participant. I already imputed the missing data, so that all time series have ...
- 3
1
vote
0
answers
120
views
How do I disable autocommit and make a batch of put operations atomic?
I’m using GridDB Cloud (Free) with the Python client, and I need to write a batch of rows to a TimeSeries container atomically (all-or-nothing). I'm having trouble figuring out how to turn autocommit ...
- 907
1
vote
1
answer
55
views
How to reverse a DolphinDB table aggregated by group by + toArray back to its original form?
I have an in - memory DolphinDB table created as follows:
ticker = `AAPL`IBM`IBM`AAPL`AMZN`AAPL`AMZN`IBM`AMZN
volume = 106 115 121 90 130 150 145 123 155;
t = table(ticker, volume);
t;
The output of ...
0
votes
1
answer
71
views
How to perform asof join (aj) with strict inequality (<) instead of default (≤)
I am using DolphinDB version 3.00.0.6 and have two in-memory tables A and B.
I need the equivalent of a Non-Equi Join with strict inequality (A.date > B.date) to find the latest record in B that is ...
- 13
2
votes
1
answer
135
views
FFT-based quasi-steady detection issue
I am trying to detect the beginning of a quasi-steady regime in time series data representing drag (Fx) and lift (Fy) forces after an initial transient.
Initially, I used a slope-based method, but it ...
- 21
0
votes
0
answers
68
views
Composite key (ts, deviceid) with timeseries container
I’m on GridDB Cloud (Free). For a TimeSeries container, I want each device to have at most one row per timestamp, i.e., enforce uniqueness on (ts, deviceid).
Schema:
CREATE TABLE TSDB (
ts TIMESTAMP ...
- 907
-2
votes
1
answer
50
views
How to efficiently calculate a custom function on a rolling window starting at specific condition-matched rows? [closed]
I'm working with minute-level stock data in DolphinDB and need to perform a specific, multi-step calculation. I'm looking for an efficient and idiomatic DolphinDB way to do this, avoiding the ...
- 15
1
vote
1
answer
86
views
Efficiently query the latest row per device in a time-series container
I’m working with GridDB Cloud (Free Tier) using the Python client (latest version on Ubuntu 22.04).
I have a container called sensor_data with this schema:
device_id STRING,
created_at TIMESTAMP,
...
- 67
4
votes
1
answer
123
views
"Top-1 Per Group”: Get the latest row per deviceid in a time range
I'm using GridDB TimeSeries and need, for a given time range, the latest row per deviceid (i.e., top-1 by timestamp within each device), returned in one query.
Expected output (example for two devices ...
- 907
3
votes
0
answers
84
views
Time-Series Pagination: LIMIT/OFFSET vs keyset (seek by last timestamp) to avoid duplicates/skips while new rows arrive?
I’m paging through a large time range in a GridDB TimeSeries container and need a pattern that won’t duplicate or skip rows if new data arrives while I’m paging.
Schema (TimeSeries):
ts (TIMESTAMP, ...
- 907