Categorygithub.com/jackc/pgx/v5
modulepackage
5.7.2
Repository: https://github.com/jackc/pgx.git
Documentation: pkg.go.dev

# README

Go Reference Build Status

pgx - PostgreSQL Driver and Toolkit

pgx is a pure Go driver and toolkit for PostgreSQL.

The pgx driver is a low-level, high performance interface that exposes PostgreSQL-specific features such as LISTEN / NOTIFY and COPY. It also includes an adapter for the standard database/sql interface.

The toolkit component is a related set of packages that implement PostgreSQL functionality such as parsing the wire protocol and type mapping between PostgreSQL and Go. These underlying packages can be used to implement alternative drivers, proxies, load balancers, logical replication clients, etc.

Example Usage

package main

import (
	"context"
	"fmt"
	"os"

	"github.com/jackc/pgx/v5"
)

func main() {
	// urlExample := "postgres://username:password@localhost:5432/database_name"
	conn, err := pgx.Connect(context.Background(), os.Getenv("DATABASE_URL"))
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to connect to database: %v\n", err)
		os.Exit(1)
	}
	defer conn.Close(context.Background())

	var name string
	var weight int64
	err = conn.QueryRow(context.Background(), "select name, weight from widgets where id=$1", 42).Scan(&name, &weight)
	if err != nil {
		fmt.Fprintf(os.Stderr, "QueryRow failed: %v\n", err)
		os.Exit(1)
	}

	fmt.Println(name, weight)
}

See the getting started guide for more information.

Features

  • Support for approximately 70 different PostgreSQL types
  • Automatic statement preparation and caching
  • Batch queries
  • Single-round trip query mode
  • Full TLS connection control
  • Binary format support for custom types (allows for much quicker encoding/decoding)
  • COPY protocol support for faster bulk data loads
  • Tracing and logging support
  • Connection pool with after-connect hook for arbitrary connection setup
  • LISTEN / NOTIFY
  • Conversion of PostgreSQL arrays to Go slice mappings for integers, floats, and strings
  • hstore support
  • json and jsonb support
  • Maps inet and cidr PostgreSQL types to netip.Addr and netip.Prefix
  • Large object support
  • NULL mapping to pointer to pointer
  • Supports database/sql.Scanner and database/sql/driver.Valuer interfaces for custom types
  • Notice response handling
  • Simulated nested transactions with savepoints

Choosing Between the pgx and database/sql Interfaces

The pgx interface is faster. Many PostgreSQL specific features such as LISTEN / NOTIFY and COPY are not available through the database/sql interface.

The pgx interface is recommended when:

  1. The application only targets PostgreSQL.
  2. No other libraries that require database/sql are in use.

It is also possible to use the database/sql interface and convert a connection to the lower-level pgx interface as needed.

Testing

See CONTRIBUTING.md for setup instructions.

Architecture

See the presentation at Golang Estonia, PGX Top to Bottom for a description of pgx architecture.

Supported Go and PostgreSQL Versions

pgx supports the same versions of Go and PostgreSQL that are supported by their respective teams. For Go that is the two most recent major releases and for PostgreSQL the major releases in the last 5 years. This means pgx supports Go 1.21 and higher and PostgreSQL 12 and higher. pgx also is tested against the latest version of CockroachDB.

Version Policy

pgx follows semantic versioning for the documented public API on stable releases. v5 is the latest stable major version.

PGX Family Libraries

github.com/jackc/pglogrepl

pglogrepl provides functionality to act as a client for PostgreSQL logical replication.

github.com/jackc/pgmock

pgmock offers the ability to create a server that mocks the PostgreSQL wire protocol. This is used internally to test pgx by purposely inducing unusual errors. pgproto3 and pgmock together provide most of the foundational tooling required to implement a PostgreSQL proxy or MitM (such as for a custom connection pooler).

github.com/jackc/tern

tern is a stand-alone SQL migration system.

github.com/jackc/pgerrcode

pgerrcode contains constants for the PostgreSQL error codes.

Adapters for 3rd Party Types

Adapters for 3rd Party Tracers

Adapters for 3rd Party Loggers

These adapters can be used with the tracelog package.

3rd Party Libraries with PGX Support

github.com/pashagolub/pgxmock

pgxmock is a mock library implementing pgx interfaces. pgxmock has one and only purpose - to simulate pgx behavior in tests, without needing a real database connection.

github.com/georgysavva/scany

Library for scanning data from a database into Go structs and more.

github.com/vingarcia/ksql

A carefully designed SQL client for making using SQL easier, more productive, and less error-prone on Golang.

github.com/otan/gopgkrb5

Adds GSSAPI / Kerberos authentication support.

github.com/wcamarao/pmx

Explicit data mapping and scanning library for Go structs and slices.

github.com/stephenafamo/scan

Type safe and flexible package for scanning database data into Go types. Supports, structs, maps, slices and custom mapping functions.

github.com/z0ne-dev/mgx

Code first migration library for native pgx (no database/sql abstraction).

# Packages

Package multitracer provides a Tracer that can combine several tracers into one.
Package pgconn is a low-level PostgreSQL database driver.
Package pgproto3 is an encoder and decoder of the PostgreSQL wire protocol version 3.
Do not edit.
Package pgxpool is a concurrency-safe connection pool for pgx.
Package pgxtest provides utilities for testing pgx and packages that integrate with pgx.
Package stdlib is the compatibility layer from pgx to database/sql.
Package tracelog provides a tracer that acts as a traditional logger.

# Functions

AppendRows iterates through rows, calling fn for each row, and appending the results into a slice of T.
BeginFunc calls Begin on db and then calls fn.
BeginTxFunc calls BeginTx on db and then calls fn.
CollectExactlyOneRow calls fn for the first row in rows and returns the result.
CollectOneRow calls fn for the first row in rows and returns the result.
CollectRows iterates through rows, calling fn for each row, and collecting the results into a slice of T.
Connect establishes a connection with a PostgreSQL server with a connection string.
ConnectConfig establishes a connection with a PostgreSQL server with a configuration struct.
ConnectWithOptions behaves exactly like Connect with the addition of options.
CopyFromFunc returns a CopyFromSource interface that relies on nxtf for values.
CopyFromRows returns a CopyFromSource interface over the provided rows slice making it usable by *Conn.CopyFrom.
CopyFromSlice returns a CopyFromSource interface over a dynamic func making it usable by *Conn.CopyFrom.
ForEachRow iterates through rows.
ParseConfig creates a ConnConfig from a connection string.
ParseConfigWithOptions behaves exactly as ParseConfig does with the addition of options.
RowsFromResultReader returns a Rows that will read from values resultReader and decode with typeMap.
RowTo returns a T scanned from row.
RowTo returns a the address of a T scanned from row.
RowToAddrOfStructByName returns the address of a T scanned from row.
RowToAddrOfStructByNameLax returns the address of a T scanned from row.
RowToAddrOfStructByPos returns the address of a T scanned from row.
RowToMap returns a map scanned from row.
RowToStructByName returns a T scanned from row.
RowToStructByNameLax returns a T scanned from row.
RowToStructByPos returns a T scanned from row.
ScanRow decodes raw row data into dest.

# Constants

PostgreSQL format codes.
Transaction deferrable modes.
Transaction deferrable modes.
Cache statement descriptions (i.e.
Automatically prepare and cache statements.
Get the statement description on every execution.
Assume the PostgreSQL query parameter types based on the Go type of the arguments.
Use the simple protocol.
Transaction isolation levels.
Transaction access modes.
Transaction isolation levels.
Transaction access modes.
Transaction isolation levels.
Transaction isolation levels.
PostgreSQL format codes.

# Variables

ErrNoRows occurs when rows are expected but none are returned.
ErrTooManyRows occurs when more rows than expected are returned.
ErrTxCommitRollback occurs when an error has occurred in a transaction and Commit() is called.

# Structs

Batch queries are a way of bundling multiple queries together to avoid unnecessary network round trips.
Conn is a PostgreSQL connection handle.
ConnConfig contains all the options used to establish a connection.
ExtendedQueryBuilder is used to choose the parameter formats, to format the parameters and to choose the result formats for an extended query.
A LargeObject is a large object stored on the server.
LargeObjects is a structure used to access the large objects API.
ParseConfigOptions contains options that control how a config is built such as getsslpassword.
QueuedQuery is a query that has been queued for execution via a Batch.
TxOptions are transaction modes within a transaction block.

# Interfaces

BatchTracer traces SendBatch.
CollectableRow is the subset of Rows methods that a RowToFunc is allowed to call.
ConnectTracer traces Connect and ConnectConfig.
CopyFromSource is the interface used by *Conn.CopyFrom as the source for copy data.
CopyFromTracer traces CopyFrom.
PrepareTracer traces Prepare.
QueryRewriter rewrites a query when used as the first arguments to a query method.
QueryTracer traces Query, QueryRow, and Exec.
Row is a convenience wrapper over Rows that is returned by QueryRow.
Rows is the result set returned from *Conn.Query.
RowScanner scans an entire row at a time into the RowScanner.
Tx represents a database transaction.

# Type aliases

Identifier a PostgreSQL identifier or name.
NamedArgs can be used as the first argument to a query method.
QueryResultFormats controls the result format (text=0, binary=1) of a query by result column position.
QueryResultFormatsByOID controls the result format (text=0, binary=1) of a query by the result column OID.
RowToFunc is a function that scans or otherwise converts row to a T.
StrictNamedArgs can be used in the same way as NamedArgs, but provided arguments are also checked to include all named arguments that the sql query uses, and no extra arguments.
TxAccessMode is the transaction access mode (read write or read only).
TxDeferrableMode is the transaction deferrable mode (deferrable or not deferrable).
TxIsoLevel is the transaction isolation level (serializable, repeatable read, read committed or read uncommitted).