panic: unsupported ClickHouse type="Map(String, String)"

[mdsohelmia]

My Model

type Video struct {
	ch.CHModel `ch:"partition:toYYYYMM(time)"`
	ID         uint64
	Title      string            `ch:""`
	Time       time.Time         `ch:",pk"`
	Meta       []uint64          `ch:"type:Array(UInt64)"`
	Chapter    map[string]string `ch:"type:Map(String,String)"`
}

	video := database.Video{
		ID:    1,
		Title: "Video 1",
		Time:  time.Now(),
		Meta:  []uint64{10, 10, 10, 10},
		Chapter: map[string]string{
			"hello1": "hello",
			"hello":  "hello",
			"title":  "title",
		},
	}
	db.NewInsert().Model(&video).Exec(ctx)

panic: unsupported ClickHouse type="Map(String, String)"

goroutine 1 [running]:
github.com/uptrace/go-clickhouse/ch/chschema.goType({0xc0000a4030, 0x13})
/Users/sohelmia/go/pkg/mod/github.com/uptrace/go-clickhouse@v0.2.9/ch/chschema/types.go:307 +0x6ce
github.com/uptrace/go-clickhouse/ch/chschema.NewColumnFromCHType({0xc0000a4030, 0x13}, 0xc00009a1e0?)
/Users/sohelmia/go/pkg/mod/github.com/uptrace/go-clickhouse@v0.2.9/ch/chschema/column.go:54 +0x28
github.com/uptrace/go-clickhouse/ch/chschema.(*Block).Column(0xc00009c280, {0xc00009a1e0, 0x7}, {0xc0000a4030, 0x13})
/Users/sohelmia/go/pkg/mod/github.com/uptrace/go-clickhouse@v0.2.9/ch/chschema/block.go:46 +0xd4
github.com/uptrace/go-clickhouse/ch.(*DB).readBlock.func1()
/Users/sohelmia/go/pkg/mod/github.com/uptrace/go-clickhouse@v0.2.9/ch/proto.go:515 +0x16e
github.com/uptrace/go-clickhouse/ch/chproto.(*Reader).WithCompression(0xc00009c000, 0x1, 0x100e4a7?)
/Users/sohelmia/go/pkg/mod/github.com/uptrace/go-clickhouse@v0.2.9/ch/chproto/reader.go:44 +0x53
github.com/uptrace/go-clickhouse/ch.(*DB).readBlock(0xc0002c8050, 0xc00009c000, 0xc00009c280, 0x1)
/Users/sohelmia/go/pkg/mod/github.com/uptrace/go-clickhouse@v0.2.9/ch/proto.go:481 +0x8f
github.com/uptrace/go-clickhouse/ch.(*DB).readSampleBlock(0x13c3820?, 0xc00009c000)
/Users/sohelmia/go/pkg/mod/github.com/uptrace/go-clickhouse@v0.2.9/ch/proto.go:382 +0x12c
github.com/uptrace/go-clickhouse/ch.(*DB)._insert.func1.2(0xc000094000?)
/Users/sohelmia/go/pkg/mod/github.com/uptrace/go-clickhouse@v0.2.9/ch/db.go:405 +0x25
github.com/uptrace/go-clickhouse/ch/chpool.(*Conn).WithReader(0xc0000a0000, {0x131b410?, 0xc00001e0c0?}, 0x13b2c64?, 0xc00035fb50)
/Users/sohelmia/go/pkg/mod/github.com/uptrace/go-clickhouse@v0.2.9/ch/chpool/conn.go:70 +0x67
github.com/uptrace/go-clickhouse/ch.(*DB)._insert.func1(0xc0000a0000)
/Users/sohelmia/go/pkg/mod/github.com/uptrace/go-clickhouse@v0.2.9/ch/db.go:404 +0x12b
github.com/uptrace/go-clickhouse/ch.(*DB)._withConn(0xc0002c8050, {0x131b410?, 0xc00001e0c0}, 0xc00035fcf8)
/Users/sohelmia/go/pkg/mod/github.com/uptrace/go-clickhouse@v0.2.9/ch/db.go:219 +0x1ec
github.com/uptrace/go-clickhouse/ch.(*DB).withConn(0xc0002c8050, {0x131b410?, 0xc00001e0c0?}, 0x12?)
/Users/sohelmia/go/pkg/mod/github.com/uptrace/go-clickhouse@v0.2.9/ch/db.go:176 +0x28
github.com/uptrace/go-clickhouse/ch.(*DB)._insert(0xc0000922a0?, {0x131b410?, 0xc00001e0c0?}, {0x1000?, 0x1000?}, {0xc0000b5000?, 0x14?}, 0x1000?)
/Users/sohelmia/go/pkg/mod/github.com/uptrace/go-clickhouse@v0.2.9/ch/db.go:396 +0x8f
github.com/uptrace/go-clickhouse/ch.(*DB).insert(0xc0002c8050, {0x131b410, 0xc00001e0c0}, {0x131afa0, 0xc0000922a0}, {0xc0000b5000, 0x46}, {0xc000092090, 0x5, 0x6})
/Users/sohelmia/go/pkg/mod/github.com/uptrace/go-clickhouse@v0.2.9/ch/db.go:383 +0x145

[et]

I'm having the same issue. This would be nice to add support as this is the datatype for storing attributes per the OTEL spec.

[vmihailenco]

Map(String, String) is just syntactic sugar for creating 2 separate columns keys and values. Here is what we use at Uptrace instead.

[et]

@vmihailenco - while it may be syntactic sugar, it is kind of nice to have it and ideally, it'd be nice to not change the schema.

How difficult would it be to add support to this library? That's my blocker for using this over the official Clickhouse client. I'd be happy to submit a PR for this if you can provide any pointers.

[vmihailenco]

@et here you go - #57. The hard part is to figure out how to implement reading/writing map[string]string using ClickHouse native protocol (ReadFrom/WriteTo methods). Most likely https://github.com/ClickHouse/clickhouse-go already knows how to do that so you can also try to ask for help there.