Background information
Candlestick charts are often used by traders and investors to perform technical analysis of stock price patterns and determine possible price movement. Additionally, candlesticks are a fundamental and core technical indicator of stocks. Multiple other indicators are derived from candlesticks. Each candlestick indicates the open, high, low, and close prices of a stock within a given time frame. Candlesticks are often generated by half an hour, day, week, month, or quarter.
Organizations in the securities sector typically receive near-real-time raw data about stock prices from stock exchanges. This data is then used to generate candlesticks, such as daily candlesticks and 5-minute candlesticks. Investors and traders have high requirements on the timeliness of data. This poses a big challenge for stock information suppliers to handle a large number of real-time computing and access requests.
TairSearch is an in-memory, full-text search data structure that integrates caching and computing for real-time data retrieval. This makes it an ideal choice for hot data caching and real-time computing to generate candlesticks. This topic provides an example on how to generate a 3-minute candlestick for a stock by using TairSearch.
Note
For more information about TairSearch, see Search.
Example
Create a schema for a stock
In this example, a data record is produced every 3 seconds. You can run the TFT.CREATEINDEX command to create a schema with the stock code as its key. The schema contains the following fields: high, low, open, close, amount, volume, and date. The date field is specified as the index.
Note
If you want to add or modify fields, run the TFT.UPDATEINDEX command.
Sample code:
TFT.CREATEINDEX 58Z074 '{
"mappings": {
"properties": {
"high": {"index": false,"type": "double"},
"low": {"index": false,"type": "double"},
"open": {"index": false,"type": "double"},
"close": {"index": false,"type": "double"},
"volume": {"index": false,"type": "long"},
"amount": {"index": false,"type": "long"},
"date": {"index": true,"type": "long"}
}
}
}'
Import data about the stock
Write the data to a TairSearch document. Sample code:
TFT.ADDDOC 58Z074 '{
"high": 1237.53,
"low": 887.54,
"open": 987.36,
"close": 997.53,
"volume": 110,
"amount": 2809,
"date": 1659922202
}'
Generate candlesticks in real time
Calculate the open, high, low, and close prices of the stock within the last 3 minutes to generate a 3-minute candlestick. Sample code:
Calculate the open price:
TFT.SEARCH 58Z074 '{
"size": 1,
"_source": {"includes": "open"},
"sort": [{"date": {"order": "asc"}}],
"query": {"range": {"date": {"gte": 1659922200,"lte": 1659922380}}}
}'
Calculate the close price:
TFT.SEARCH 58Z074 '{
"size": 1,
"_source": {"includes": "close"},
"sort": [{"date": {"order": "desc"}}],
"query": {"range": {"date": {"gte": 1659922200,"lte": 1659922380}}}
}'
Calculate the high and low prices:
TFT.SEARCH 58Z074 '{
"size": 0,
"query": {"range": {"date": {"gte": 1659922200,"lte": 1659922380}}},
"aggs": {"high": {"max": {"field": "high"}},"low": {"min": {"field": "low"}}}
}'
Generate a candlestick chart for the stock
The following figure shows the candlestick chart generated by using the Pyecharts library.
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