Upload large CSV file to SQL database

While default nodes are sufficient to upload small datasets to a database via Node-RED, they do not suffice when handling files of tens of megabytes, let alone gigabytes, which cannot fit in memory.

We take advantage of two special nodes:

• node-red-contrib-ui-upload, able to upload (using streaming) large files from a Node-RED Dashboard.
• node-red-contrib-chunks-to-lines able to convert large upload streams into text lines

For this example, we assume the input file is in CSV format – but it could be something else – and we use the default CSV node to parse the text lines.

For this example, we use a PostgreSQL database (with optional Timescale extension for better handling of time-series) – but it could be another database – thanks to the node-red-contrib-postgresql node.

Configuration details

• The ui-upload node is set to chunks of 256kB in binary mode. Our tests show that this provides good speed and stability.
• The chunks-to-lines is set to CSV node (for compatibility with the default CSV node), UTF-8 encoding (should be the same than the uploaded file), and outputting 4096 lines at a time. Inserting many lines at a time in database is much faster than one at a time.
• The CSV node is set to “first row contains column names”, and “output a single message (array)”. Obviously, the separator (comma by default) must be the same than your uploaded file.
• The postgres node is set to “receive query output”, in order to know when the insertion of a batch of lines in database is done and to trigger the next one.

Usage

1. Adapt to your database parameters (e.g. database name, column names)
2. Browse to the Node-RED Dashboard
3. Click on the Prepare SQL table button to create a blank table in database
4. In the Upload to SQL section, select a local CSV file on your computer (with columns: time, sensor, data). See sample.csv for an example of mini dataset.
5. Wait for upload
6. The number of uploaded lines appears in the Dashboard
7. You can inspect your database using another tool

Screenshots

Dashboard during upload

Dashboard when upload is complete

Copy[{"id":"e6ec0f0a.388198","type":"chunks-to-lines","z":"d9a661f4.ef966","name":"","nbLines":"4096","linesFormat":"csv","decoder":"UTF-8","x":280,"y":940,"wires":[["436dce51.065f6"]]},{"id":"a2a16dc6.fbd32","type":"function","z":"d9a661f4.ef966","name":"Ready for next lines","func":"return [\n    msg.complete ? msg : null,\n    { tick: true },\n];\n","outputs":2,"noerr":0,"initialize":"","finalize":"","libs":[],"x":940,"y":880,"wires":[["87fbc09b.6deeb","35615002.196b78"],["e6ec0f0a.388198"]]},{"id":"436dce51.065f6","type":"csv","z":"d9a661f4.ef966","name":"","sep":",","hdrin":true,"hdrout":"none","multi":"mult","ret":"\\n","temp":"","skip":"0","strings":false,"include_empty_strings":"","include_null_values":"","x":430,"y":940,"wires":[["4127dd44.2d49d4"]]},{"id":"4127dd44.2d49d4","type":"function","z":"d9a661f4.ef966","name":"Format SQL","func":"if (msg.payload && msg.payload.length > 0) {\n    let payload = 'INSERT INTO your_table(time, sensor, data) VALUES ';\n    \n    for (const line of msg.payload) {\n        payload += `('${line.time}', '${line.sensor}', '${line.data}'),`;\n    }\n    \n    msg.payload = payload.slice(0, - 1) + ';';\n}\nreturn msg;\n","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":570,"y":940,"wires":[["65c0779b0f924c8b"]]},{"id":"d5504079.651a68","type":"comment","z":"d9a661f4.ef966","name":"Upload to SQL","info":"","x":120,"y":780,"wires":[]},{"id":"715380a8.42ec7","type":"debug","z":"d9a661f4.ef966","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":530,"y":840,"wires":[]},{"id":"87fbc09b.6deeb","type":"debug","z":"d9a661f4.ef966","name":"Done","active":true,"tosidebar":true,"console":false,"tostatus":true,"complete":"true","targetType":"full","statusVal":"_parts.lines","statusType":"msg","x":1170,"y":940,"wires":[]},{"id":"4b31cec2.dad2c8","type":"ui_upload","z":"d9a661f4.ef966","group":"593aaad02ba9e607","title":"Generic upload to SQL","name":"uploadSql","order":3,"width":6,"height":6,"chunk":"256","transfer":"binary","x":100,"y":940,"wires":[["e6ec0f0a.388198"]]},{"id":"35615002.196b78","type":"ui_text","z":"d9a661f4.ef966","group":"6426525.5bfe1ac","order":3,"width":0,"height":0,"name":"","label":"Lines uploaded:","format":"{{msg._parts.lines}}","layout":"row-spread","x":1200,"y":880,"wires":[]},{"id":"65d2e9d6.5ca5","type":"ui_button","z":"d9a661f4.ef966","name":"","group":"593aaad02ba9e607","order":1,"width":0,"height":0,"passthru":false,"label":"Prepare generic SQL table","tooltip":"","color":"","bgcolor":"","icon":"","payload":"","payloadType":"str","topic":"","topicType":"str","x":160,"y":840,"wires":[["6b76c340a580b0a4"]]},{"id":"6b76c340a580b0a4","type":"postgresql","z":"d9a661f4.ef966","name":"","query":"DROP TABLE IF EXISTS your_table;\nCREATE TABLE your_table (\n\tid\t\tSERIAL\tNOT NULL,\n\ttime\tTIMESTAMP WITH TIME ZONE\tNOT NULL,\n\tsensor\tTEXT,\n\tdata\tJSONB\n);\n\nSELECT create_hypertable('your_table', 'time');\nCREATE INDEX IF NOT EXISTS index_sensor ON your_table(\"sensor\");\n","postgreSQLConfig":"20ae1e52d1eef983","split":false,"rowsPerMsg":1,"outputs":1,"x":370,"y":840,"wires":[["715380a8.42ec7"]]},{"id":"65c0779b0f924c8b","type":"postgresql","z":"d9a661f4.ef966","name":"","query":"{{{ msg.payload }}}","postgreSQLConfig":"20ae1e52d1eef983","split":false,"rowsPerMsg":1,"outputs":1,"x":730,"y":940,"wires":[["a2a16dc6.fbd32"]]},{"id":"593aaad02ba9e607","type":"ui_group","name":"Default","tab":"5f17e3a3.4c85ac","order":1,"disp":true,"width":"6","collapse":false},{"id":"6426525.5bfe1ac","type":"ui_group","name":"Default","tab":"cb135bc2.cc3d9","order":1,"disp":true,"width":"6","collapse":true},{"id":"20ae1e52d1eef983","type":"postgreSQLConfig","name":"admin@timescale:5432/iot","host":"timescale","hostFieldType":"str","port":"5432","portFieldType":"num","database":"iot","databaseFieldType":"str","ssl":"false","sslFieldType":"bool","max":"10","maxFieldType":"num","min":"1","minFieldType":"num","idle":"1000","idleFieldType":"num","connectionTimeout":"10000","connectionTimeoutFieldType":"num","user":"admin","userFieldType":"str","password":"RTffY87xVqGA","passwordFieldType":"str"},{"id":"5f17e3a3.4c85ac","type":"ui_tab","name":"Generic demo","icon":"dashboard","disabled":false,"hidden":false},{"id":"cb135bc2.cc3d9","type":"ui_tab","name":"Anomaly","icon":"dashboard","disabled":false,"hidden":false}]