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glenjamin/docker-compose.yml

Last active November 5, 2025 15:35
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Postgres slice value/scanning
Raw
docker-compose.yml
services:
postgres:
image: "postgres:16.3"
environment:
POSTGRES_HOST_AUTH_METHOD: trust
PGUSER: postgres # make it so `exec psql` works
ports:
- "127.0.0.1:5432:5432"
Raw
go.mod
module github.com/geckoboard/pgx-slices
go 1.24.9
require (
github.com/duckdb/duckdb-go/v2 v2.5.1
github.com/jackc/pgx/v5 v5.7.6
github.com/lib/pq v1.10.9
)
require (
github.com/apache/arrow-go/v18 v18.4.1 // indirect
github.com/duckdb/duckdb-go-bindings v0.1.22 // indirect
github.com/duckdb/duckdb-go-bindings/darwin-amd64 v0.1.22 // indirect
github.com/duckdb/duckdb-go-bindings/darwin-arm64 v0.1.22 // indirect
github.com/duckdb/duckdb-go-bindings/linux-amd64 v0.1.22 // indirect
github.com/duckdb/duckdb-go-bindings/linux-arm64 v0.1.22 // indirect
github.com/duckdb/duckdb-go-bindings/windows-amd64 v0.1.22 // indirect
github.com/duckdb/duckdb-go/arrowmapping v0.0.24 // indirect
github.com/duckdb/duckdb-go/mapping v0.0.24 // indirect
github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
github.com/goccy/go-json v0.10.5 // indirect
github.com/google/flatbuffers v25.2.10+incompatible // indirect
github.com/google/uuid v1.6.0 // indirect
github.com/jackc/pgpassfile v1.0.0 // indirect
github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
github.com/jackc/puddle/v2 v2.2.2 // indirect
github.com/klauspost/compress v1.18.0 // indirect
github.com/klauspost/cpuid/v2 v2.3.0 // indirect
github.com/pierrec/lz4/v4 v4.1.22 // indirect
github.com/zeebo/xxh3 v1.0.2 // indirect
golang.org/x/crypto v0.37.0 // indirect
golang.org/x/exp v0.0.0-20250408133849-7e4ce0ab07d0 // indirect
golang.org/x/mod v0.27.0 // indirect
golang.org/x/sync v0.16.0 // indirect
golang.org/x/sys v0.35.0 // indirect
golang.org/x/text v0.28.0 // indirect
golang.org/x/tools v0.36.0 // indirect
golang.org/x/xerrors v0.0.0-20240903120638-7835f813f4da // indirect
)
Raw
go.sum
github.com/andybalholm/brotli v1.2.0 h1:ukwgCxwYrmACq68yiUqwIWnGY0cTPox/M94sVwToPjQ=
github.com/andybalholm/brotli v1.2.0/go.mod h1:rzTDkvFWvIrjDXZHkuS16NPggd91W3kUSvPlQ1pLaKY=
github.com/apache/arrow-go/v18 v18.4.1 h1:q/jVkBWCJOB9reDgaIZIdruLQUb1kbkvOnOFezVH1C4=
github.com/apache/arrow-go/v18 v18.4.1/go.mod h1:tLyFubsAl17bvFdUAy24bsSvA/6ww95Iqi67fTpGu3E=
github.com/apache/thrift v0.22.0 h1:r7mTJdj51TMDe6RtcmNdQxgn9XcyfGDOzegMDRg47uc=
github.com/apache/thrift v0.22.0/go.mod h1:1e7J/O1Ae6ZQMTYdy9xa3w9k+XHWPfRvdPyJeynQ+/g=
github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/duckdb/duckdb-go-bindings v0.1.22 h1:TnkBfSS+UAyOWT6NazyZ+bWDcA+ft8S3Hl+c1SNOkcc=
github.com/duckdb/duckdb-go-bindings v0.1.22/go.mod h1:pBnfviMzANT/9hi4bg+zW4ykRZZPCXlVuvBWEcZofkc=
github.com/duckdb/duckdb-go-bindings/darwin-amd64 v0.1.22 h1:kL5Om34dyDt08jtwOqJcjZRf1H2hrjd5ZrhXPNcXrj0=
github.com/duckdb/duckdb-go-bindings/darwin-amd64 v0.1.22/go.mod h1:Ezo7IbAfB8NP7CqPIN8XEHKUg5xdRRQhcPPlCXImXYA=
github.com/duckdb/duckdb-go-bindings/darwin-arm64 v0.1.22 h1:uaQhaTl8+Oz12kSYIkIf1OTWyzCm1CrtYgZoEytciBI=
github.com/duckdb/duckdb-go-bindings/darwin-arm64 v0.1.22/go.mod h1:eS7m/mLnPQgVF4za1+xTyorKRBuK0/BA44Oy6DgrGXI=
github.com/duckdb/duckdb-go-bindings/linux-amd64 v0.1.22 h1:yKH78pbt7TtLekdyIePbIM0+gGrMpbj4EnblcqxHOB4=
github.com/duckdb/duckdb-go-bindings/linux-amd64 v0.1.22/go.mod h1:1GOuk1PixiESxLaCGFhag+oFi7aP+9W8byymRAvunBk=
github.com/duckdb/duckdb-go-bindings/linux-arm64 v0.1.22 h1:swAVmk7h5PmGTXvwd5q0mNcZlMFGiaCcDnuuyqmSd0E=
github.com/duckdb/duckdb-go-bindings/linux-arm64 v0.1.22/go.mod h1:o7crKMpT2eOIi5/FY6HPqaXcvieeLSqdXXaXbruGX7w=
github.com/duckdb/duckdb-go-bindings/windows-amd64 v0.1.22 h1:5PC3g7h0KA3kuN6GrEb+NDe0SP561CH+QrsEi1n3iZ0=
github.com/duckdb/duckdb-go-bindings/windows-amd64 v0.1.22/go.mod h1:IlOhJdVKUJCAPj3QsDszUo8DVdvp1nBFp4TUJVdw99s=
github.com/duckdb/duckdb-go/arrowmapping v0.0.24 h1:D+uRf9vIbT0OOcyuhtXgIL1RI9N5VlTt8kRxP4SpQbc=
github.com/duckdb/duckdb-go/arrowmapping v0.0.24/go.mod h1:lkSShVua0s9FrRtx5EgLvEItyuoKdL4zP6pjL2J485Y=
github.com/duckdb/duckdb-go/mapping v0.0.24 h1:w1I5JuTMFWdRqBzfmJ2fpefEEVaNgBnuho6kuGIJ9pM=
github.com/duckdb/duckdb-go/mapping v0.0.24/go.mod h1:syxQeEWTeGb8JqdyfVPvlpJepdyliVM88EauJPxggto=
github.com/duckdb/duckdb-go/v2 v2.5.1 h1:KDGqhQfXkjlV5pRxbxY3HpRUd6sip5HS9XOL6s0qQbs=
github.com/duckdb/duckdb-go/v2 v2.5.1/go.mod h1:DRMOapsta2PlFZtlWrxyC5CqucD0q5GZH/KRkTTnPUU=
github.com/go-viper/mapstructure/v2 v2.4.0 h1:EBsztssimR/CONLSZZ04E8qAkxNYq4Qp9LvH92wZUgs=
github.com/go-viper/mapstructure/v2 v2.4.0/go.mod h1:oJDH3BJKyqBA2TXFhDsKDGDTlndYOZ6rGS0BRZIxGhM=
github.com/goccy/go-json v0.10.5 h1:Fq85nIqj+gXn/S5ahsiTlK3TmC85qgirsdTP/+DeaC4=
github.com/goccy/go-json v0.10.5/go.mod h1:oq7eo15ShAhp70Anwd5lgX2pLfOS3QCiwU/PULtXL6M=
github.com/golang/snappy v1.0.0 h1:Oy607GVXHs7RtbggtPBnr2RmDArIsAefDwvrdWvRhGs=
github.com/golang/snappy v1.0.0/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
github.com/google/flatbuffers v25.2.10+incompatible h1:F3vclr7C3HpB1k9mxCGRMXq6FdUalZ6H/pNX4FP1v0Q=
github.com/google/flatbuffers v25.2.10+incompatible/go.mod h1:1AeVuKshWv4vARoZatz6mlQ0JxURH0Kv5+zNeJKJCa8=
github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=
github.com/jackc/pgpassfile v1.0.0/go.mod h1:CEx0iS5ambNFdcRtxPj5JhEz+xB6uRky5eyVu/W2HEg=
github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 h1:iCEnooe7UlwOQYpKFhBabPMi4aNAfoODPEFNiAnClxo=
github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761/go.mod h1:5TJZWKEWniPve33vlWYSoGYefn3gLQRzjfDlhSJ9ZKM=
github.com/jackc/pgx/v5 v5.7.6 h1:rWQc5FwZSPX58r1OQmkuaNicxdmExaEz5A2DO2hUuTk=
github.com/jackc/pgx/v5 v5.7.6/go.mod h1:aruU7o91Tc2q2cFp5h4uP3f6ztExVpyVv88Xl/8Vl8M=
github.com/jackc/puddle/v2 v2.2.2 h1:PR8nw+E/1w0GLuRFSmiioY6UooMp6KJv0/61nB7icHo=
github.com/jackc/puddle/v2 v2.2.2/go.mod h1:vriiEXHvEE654aYKXXjOvZM39qJ0q+azkZFrfEOc3H4=
github.com/klauspost/asmfmt v1.3.2 h1:4Ri7ox3EwapiOjCki+hw14RyKk201CN4rzyCJRFLpK4=
github.com/klauspost/asmfmt v1.3.2/go.mod h1:AG8TuvYojzulgDAMCnYn50l/5QV3Bs/tp6j0HLHbNSE=
github.com/klauspost/compress v1.18.0 h1:c/Cqfb0r+Yi+JtIEq73FWXVkRonBlf0CRNYc8Zttxdo=
github.com/klauspost/compress v1.18.0/go.mod h1:2Pp+KzxcywXVXMr50+X0Q/Lsb43OQHYWRCY2AiWywWQ=
github.com/klauspost/cpuid/v2 v2.3.0 h1:S4CRMLnYUhGeDFDqkGriYKdfoFlDnMtqTiI/sFzhA9Y=
github.com/klauspost/cpuid/v2 v2.3.0/go.mod h1:hqwkgyIinND0mEev00jJYCxPNVRVXFQeu1XKlok6oO0=
github.com/lib/pq v1.10.9 h1:YXG7RB+JIjhP29X+OtkiDnYaXQwpS4JEWq7dtCCRUEw=
github.com/lib/pq v1.10.9/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
github.com/minio/asm2plan9s v0.0.0-20200509001527-cdd76441f9d8 h1:AMFGa4R4MiIpspGNG7Z948v4n35fFGB3RR3G/ry4FWs=
github.com/minio/asm2plan9s v0.0.0-20200509001527-cdd76441f9d8/go.mod h1:mC1jAcsrzbxHt8iiaC+zU4b1ylILSosueou12R++wfY=
github.com/minio/c2goasm v0.0.0-20190812172519-36a3d3bbc4f3 h1:+n/aFZefKZp7spd8DFdX7uMikMLXX4oubIzJF4kv/wI=
github.com/minio/c2goasm v0.0.0-20190812172519-36a3d3bbc4f3/go.mod h1:RagcQ7I8IeTMnF8JTXieKnO4Z6JCsikNEzj0DwauVzE=
github.com/pierrec/lz4/v4 v4.1.22 h1:cKFw6uJDK+/gfw5BcDL0JL5aBsAFdsIT18eRtLj7VIU=
github.com/pierrec/lz4/v4 v4.1.22/go.mod h1:gZWDp/Ze/IJXGXf23ltt2EXimqmTUXEy0GFuRQyBid4=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
github.com/stretchr/testify v1.11.0 h1:ib4sjIrwZKxE5u/Japgo/7SJV3PvgjGiRNAvTVGqQl8=
github.com/stretchr/testify v1.11.0/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
github.com/zeebo/assert v1.3.0 h1:g7C04CbJuIDKNPFHmsk4hwZDO5O+kntRxzaUoNXj+IQ=
github.com/zeebo/assert v1.3.0/go.mod h1:Pq9JiuJQpG8JLJdtkwrJESF0Foym2/D9XMU5ciN/wJ0=
github.com/zeebo/xxh3 v1.0.2 h1:xZmwmqxHZA8AI603jOQ0tMqmBr9lPeFwGg6d+xy9DC0=
github.com/zeebo/xxh3 v1.0.2/go.mod h1:5NWz9Sef7zIDm2JHfFlcQvNekmcEl9ekUZQQKCYaDcA=
golang.org/x/crypto v0.37.0 h1:kJNSjF/Xp7kU0iB2Z+9viTPMW4EqqsrywMXLJOOsXSE=
golang.org/x/crypto v0.37.0/go.mod h1:vg+k43peMZ0pUMhYmVAWysMK35e6ioLh3wB8ZCAfbVc=
golang.org/x/exp v0.0.0-20250408133849-7e4ce0ab07d0 h1:R84qjqJb5nVJMxqWYb3np9L5ZsaDtB+a39EqjV0JSUM=
golang.org/x/exp v0.0.0-20250408133849-7e4ce0ab07d0/go.mod h1:S9Xr4PYopiDyqSyp5NjCrhFrqg6A5zA2E/iPHPhqnS8=
golang.org/x/mod v0.27.0 h1:kb+q2PyFnEADO2IEF935ehFUXlWiNjJWtRNgBLSfbxQ=
golang.org/x/mod v0.27.0/go.mod h1:rWI627Fq0DEoudcK+MBkNkCe0EetEaDSwJJkCcjpazc=
golang.org/x/sync v0.16.0 h1:ycBJEhp9p4vXvUZNszeOq0kGTPghopOL8q0fq3vstxw=
golang.org/x/sync v0.16.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
golang.org/x/sys v0.35.0 h1:vz1N37gP5bs89s7He8XuIYXpyY0+QlsKmzipCbUtyxI=
golang.org/x/sys v0.35.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
golang.org/x/text v0.28.0 h1:rhazDwis8INMIwQ4tpjLDzUhx6RlXqZNPEM0huQojng=
golang.org/x/text v0.28.0/go.mod h1:U8nCwOR8jO/marOQ0QbDiOngZVEBB7MAiitBuMjXiNU=
golang.org/x/tools v0.36.0 h1:kWS0uv/zsvHEle1LbV5LE8QujrxB3wfQyxHfhOk0Qkg=
golang.org/x/tools v0.36.0/go.mod h1:WBDiHKJK8YgLHlcQPYQzNCkUxUypCaa5ZegCVutKm+s=
golang.org/x/xerrors v0.0.0-20240903120638-7835f813f4da h1:noIWHXmPHxILtqtCOPIhSt0ABwskkZKjD3bXGnZGpNY=
golang.org/x/xerrors v0.0.0-20240903120638-7835f813f4da/go.mod h1:NDW/Ps6MPRej6fsCIbMTohpP40sJ/P/vI1MoTEGwX90=
gonum.org/v1/gonum v0.16.0 h1:5+ul4Swaf3ESvrOnidPp4GZbzf0mxVQpDCYUQE7OJfk=
gonum.org/v1/gonum v0.16.0/go.mod h1:fef3am4MQ93R2HHpKnLk4/Tbh/s0+wqD5nfa6Pnwy4E=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
Raw
main.go
package main
import (
"database/sql"
"fmt"
_ "github.com/duckdb/duckdb-go/v2"
"github.com/jackc/pgx/v5/pgtype"
_ "github.com/jackc/pgx/v5/stdlib"
"github.com/lib/pq"
_ "github.com/lib/pq"
)
var typemap = pgtype.NewMap()
type stringList []string
func (s *stringList) Scan(src any) error {
switch v := src.(type) {
case string:
var result []string
err := typemap.SQLScanner(&result).Scan(src)
if err != nil {
return err
}
*s = result
case []byte:
var result pq.StringArray
if err := result.Scan(src); err != nil {
return err
}
*s = []string(result)
case []any:
*s = make(stringList, len(v))
for i, vv := range v {
(*s)[i] = vv.(string)
}
}
return nil
}
func main() {
pgx, err := sql.Open("pgx",
"postgres://postgres:postgres@localhost/postgres?sslmode=disable")
noError(err)
test("pgx", pgx)
duck, err := sql.Open("duckdb", "")
noError(err)
test("duckdb", duck)
pq, err := sql.Open("postgres2",
"postgres://postgres:postgres@localhost/postgres?sslmode=disable")
noError(err)
test("lib/pq", pq)
}
func test(label string, db *sql.DB) {
println(label)
_, err := db.Exec("CREATE TABLE IF NOT EXISTS a(i INT, xs VARCHAR[])")
noError(err)
_, err = db.Exec("TRUNCATE TABLE a")
noError(err)
_, err = db.Exec("INSERT INTO a VALUES($1, $2)", 1, stringList{"a", "b"})
noError(err)
_, err = db.Exec("INSERT INTO a VALUES($1, $2)", 2, nil)
noError(err)
var result1 []string
err = db.QueryRow("SELECT xs FROM a WHERE i = $1 limit 1", 1).Scan(&result1)
logError("slice scan", err)
fmt.Printf("slice scan result: %#v\n", result1)
var result2 stringList
err = db.QueryRow("SELECT xs FROM a WHERE i = $1 limit 1", 1).Scan(&result2)
logError("stringList scan", err)
fmt.Printf("stringList scan result: %#v\n", result2)
}
func noError(err error) {
if err != nil {
panic(err)
}
}
func logError(op string, err error) {
if err != nil {
fmt.Printf("%s error: %#v\n", op, err)
}
}
Raw
pq2.go
package main
import (
"database/sql"
"database/sql/driver"
"github.com/lib/pq"
)
type Driver struct {
}
func (d *Driver) Open(name string) (driver.Conn, error) {
conn, err := pq.Open(name)
if err != nil {
return nil, err
}
return &Conn{conn}, nil
}
type Conn struct {
driver.Conn
}
func (c Conn) CheckNamedValue(value *driver.NamedValue) (err error) {
switch v := value.Value.(type) {
case []string:
value.Value, err = pq.StringArray(v).Value()
return err
case stringList:
value.Value, err = pq.StringArray(v).Value()
return err
}
return driver.ErrSkip
}
func init() {
sql.Register("postgres2", &Driver{})
}
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