Timestamp conversion failing?

[jvilhuber]

I'm very likely doing something wrong. Could use a clue. I have a struct I'm using to translate from json to parquet files. I have not figured out how to use the same 'time.Time' field for both json and parquet, so I have these two fields:

	Timestamp         time.Time `json:"@timestamp"`
	ParquetTimestamp  int64     `parquet:"name=timestamp, type=INT64, convertedType=TIMESTAMP_MILLIS"`

I also tried

	ParquetTimestamp  int64     `parquet:"name=timestamp, type=INT64, logicaltype=TIMESTAMP, logicaltype.isadjustedtoutc=true, logicaltype.unit=MILLIS"`

The json file has something like

    "@timestamp": "2024-08-19T12:14:17+00:00",

Json decoding works fine and I have a valid, non-zero timestamp in go (verified with the debugger). In the code, I then do this:

			logEntry.ParquetTimestamp = logEntry.Timestamp.UnixMilli()

And then I write out the parquet using the normal mechanisms. I've verified that the value assigned to logEntry.ParquetTimestamp is not 0 at this point.

However it appears that I always wind up with a 0 timestamp in the parquet files. Using parquet cat to dump the file, I see

{"timestamp": 0...

Can anyone tell me what I'm doing wrong?

[jvilhuber]

If I investigate with parquet schema I see

$ parquet schema logfile.parquet
{
  "type" : "record",
  "name" : "parquet_go_root",
  "fields" : [ {
    "name" : "timestamp",
    "type" : {
      "type" : "long",
      "logicalType" : "local-timestamp-millis"
    }
  }, {...

[hangxie]

Works for me

package main

import (
	"fmt"
	"os"
	"time"

	"github.com/xitongsys/parquet-go/writer"
)

type Example struct {
	ParquetTimestamp int64 `parquet:"name=timestamp, type=INT64, convertedType=TIMESTAMP_MILLIS"`
}

func main() {
	w, err := os.Create("timestamp.parquet")
	if err != nil {
		fmt.Println("Can't create local file", err)
		return
	}

	pw, err := writer.NewParquetWriterFromWriter(w, new(Example), 4)
	if err != nil {
		fmt.Println("Can't create parquet writer", err)
		return
	}

	ex := Example{
		ParquetTimestamp: time.Now().UnixMilli(),
	}
	if err = pw.Write(ex); err != nil {
		fmt.Println("Write error", err)
	}
	if err = pw.WriteStop(); err != nil {
		fmt.Println("WriteStop error", err)
		return
	}
	fmt.Println("Write Finished")
	w.Close()

}

Then

$ go run timestamp.go
Write Finished
$ parquet cat timestamp.parquet
{"timestamp": 1727915144666}
$ parquet schema timestamp.parquet
{
  "type" : "record",
  "name" : "parquet_go_root",
  "fields" : [ {
    "name" : "timestamp",
    "type" : {
      "type" : "long",
      "logicalType" : "local-timestamp-millis"
    }
  } ]
}