CopyFrom had to create a prepared statement to get the OIDs of the data types that were going to be copied into the table. Every COPY operation required an extra round trips to retrieve the type information. There was no way to customize this behavior. By leveraging the QueryExecMode feature, like in `Conn.Query`, users can specify if they want to cache the prepared statements, execute them on every request (like the old behavior), or bypass the prepared statement relying on the pgtype.Map to get the type information. The `QueryExecMode` behave exactly like in `Conn.Query` in the way the data type OIDs are fetched, meaning that: - `QueryExecModeCacheStatement`: caches the statement. - `QueryExecModeCacheDescribe`: caches the statement and assumes they do not change. - `QueryExecModeDescribeExec`: gets the statement description on every execution. This is like to the old behavior of `CopyFrom`. - `QueryExecModeExec` and `QueryExecModeSimpleProtocol`: maintain the same behavior as before, which is the same as `QueryExecModeDescribeExec`. It will keep getting the statement description on every execution The `QueryExecMode` can only be set via `ConnConfig.DefaultQueryExecMode`, unlike `Conn.Query` there's no support for specifying the `QueryExecMode` via optional arguments in the function signature.
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
supportjson
andjsonb
support- Maps
inet
andcidr
PostgreSQL types tonetip.Addr
andnetip.Prefix
- Large object support
- NULL mapping to pointer to pointer
- Supports
database/sql.Scanner
anddatabase/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:
- The application only targets PostgreSQL.
- 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.
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 1.18 and higher and PostgreSQL 11 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
- github.com/jackc/pgx-gofrs-uuid
- github.com/jackc/pgx-shopspring-decimal
- github.com/vgarvardt/pgx-google-uuid
Adapters for 3rd Party Tracers
Adapters for 3rd Party Loggers
These adapters can be used with the tracelog package.
- github.com/jackc/pgx-go-kit-log
- github.com/jackc/pgx-log15
- github.com/jackc/pgx-logrus
- github.com/jackc/pgx-zap
- github.com/jackc/pgx-zerolog
3rd Party Libraries with PGX Support
github.com/georgysavva/scany
Library for scanning data from a database into Go structs and more.
https://github.com/otan/gopgkrb5
Adds GSSAPI / Kerberos authentication support.