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Replace connection pool

pull/483/head
Jack Christensen 2019-04-10 11:09:42 -05:00
parent ec10fdde8b
commit 77a2da2b46
9 changed files with 42 additions and 1602 deletions
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5
batch.go
View File

@ -19,7 +19,6 @@ type batchItem struct {
// unnecessary network round trips. // unnecessary network round trips.
type Batch struct { type Batch struct {
conn *Conn conn *Conn
connPool *ConnPool
items []*batchItem items []*batchItem
resultsRead int resultsRead int
pendingCommandComplete bool pendingCommandComplete bool
@ -188,8 +187,4 @@ func (b *Batch) die(err error) {
b.err = err b.err = err
b.conn.die(err) b.conn.die(err)
if b.conn != nil && b.connPool != nil {
b.connPool.Release(b.conn)
}
} }

59
bench_test.go
View File

@ -13,45 +13,6 @@ import (
"github.com/jackc/pgx/pgtype" "github.com/jackc/pgx/pgtype"
) )
func BenchmarkConnPool(b *testing.B) {
config := pgx.ConnPoolConfig{ConnConfig: mustParseConfig(b, os.Getenv("PGX_TEST_DATABASE")), MaxConnections: 5}
pool, err := pgx.NewConnPool(config)
if err != nil {
b.Fatalf("Unable to create connection pool: %v", err)
}
defer pool.Close()
b.ResetTimer()
for i := 0; i < b.N; i++ {
var conn *pgx.Conn
if conn, err = pool.Acquire(); err != nil {
b.Fatalf("Unable to acquire connection: %v", err)
}
pool.Release(conn)
}
}
func BenchmarkConnPoolQueryRow(b *testing.B) {
config := pgx.ConnPoolConfig{ConnConfig: mustParseConfig(b, os.Getenv("PGX_TEST_DATABASE")), MaxConnections: 5}
pool, err := pgx.NewConnPool(config)
if err != nil {
b.Fatalf("Unable to create connection pool: %v", err)
}
defer pool.Close()
b.ResetTimer()
for i := 0; i < b.N; i++ {
num := float64(-1)
if err := pool.QueryRow("select random()").Scan(&num); err != nil {
b.Fatal(err)
}
if num < 0 {
b.Fatalf("expected `select random()` to return between 0 and 1 but it was: %v", num)
}
}
}
func BenchmarkPointerPointerWithNullValues(b *testing.B) { func BenchmarkPointerPointerWithNullValues(b *testing.B) {
conn := mustConnect(b, mustParseConfig(b, os.Getenv("PGX_TEST_DATABASE"))) conn := mustConnect(b, mustParseConfig(b, os.Getenv("PGX_TEST_DATABASE")))
defer closeConn(b, conn) defer closeConn(b, conn)
@ -613,19 +574,15 @@ func BenchmarkWrite10000RowsViaCopy(b *testing.B) {
} }
func BenchmarkMultipleQueriesNonBatch(b *testing.B) { func BenchmarkMultipleQueriesNonBatch(b *testing.B) {
config := pgx.ConnPoolConfig{ConnConfig: mustParseConfig(b, os.Getenv("PGX_TEST_DATABASE")), MaxConnections: 5} conn := mustConnect(b, mustParseConfig(b, os.Getenv("PGX_TEST_DATABASE")))
pool, err := pgx.NewConnPool(config) defer closeConn(b, conn)
if err != nil {
b.Fatalf("Unable to create connection pool: %v", err)
}
defer pool.Close()
queryCount := 3 queryCount := 3
b.ResetTimer() b.ResetTimer()
for i := 0; i < b.N; i++ { for i := 0; i < b.N; i++ {
for j := 0; j < queryCount; j++ { for j := 0; j < queryCount; j++ {
rows, err := pool.Query("select n from generate_series(0, 5) n") rows, err := conn.Query("select n from generate_series(0, 5) n")
if err != nil { if err != nil {
b.Fatal(err) b.Fatal(err)
} }
@ -648,18 +605,14 @@ func BenchmarkMultipleQueriesNonBatch(b *testing.B) {
} }
func BenchmarkMultipleQueriesBatch(b *testing.B) { func BenchmarkMultipleQueriesBatch(b *testing.B) {
config := pgx.ConnPoolConfig{ConnConfig: mustParseConfig(b, os.Getenv("PGX_TEST_DATABASE")), MaxConnections: 5} conn := mustConnect(b, mustParseConfig(b, os.Getenv("PGX_TEST_DATABASE")))
pool, err := pgx.NewConnPool(config) defer closeConn(b, conn)
if err != nil {
b.Fatalf("Unable to create connection pool: %v", err)
}
defer pool.Close()
queryCount := 3 queryCount := 3
b.ResetTimer() b.ResetTimer()
for i := 0; i < b.N; i++ { for i := 0; i < b.N; i++ {
batch := pool.BeginBatch() batch := conn.BeginBatch()
for j := 0; j < queryCount; j++ { for j := 0; j < queryCount; j++ {
batch.Queue("select n from generate_series(0,5) n", batch.Queue("select n from generate_series(0,5) n",
nil, nil,

550
conn_pool.go
View File

@ -1,550 +0,0 @@
package pgx
import (
"context"
"sync"
"time"
"github.com/pkg/errors"
"github.com/jackc/pgconn"
"github.com/jackc/pgx/pgtype"
)
type ConnPoolConfig struct {
ConnConfig
MaxConnections int // max simultaneous connections to use, default 5, must be at least 2
AfterConnect func(*Conn) error // function to call on every new connection
AcquireTimeout time.Duration // max wait time when all connections are busy (0 means no timeout)
}
type ConnPool struct {
allConnections []*Conn
availableConnections []*Conn
cond *sync.Cond
config ConnConfig // config used when establishing connection
inProgressConnects int
maxConnections int
resetCount int
afterConnect func(*Conn) error
logger Logger
logLevel LogLevel
closed bool
preparedStatements map[string]*PreparedStatement
acquireTimeout time.Duration
connInfo *pgtype.ConnInfo
}
type ConnPoolStat struct {
MaxConnections int // max simultaneous connections to use
CurrentConnections int // current live connections
AvailableConnections int // unused live connections
}
// CheckedOutConnections returns the amount of connections that are currently
// checked out from the pool.
func (stat *ConnPoolStat) CheckedOutConnections() int {
return stat.CurrentConnections - stat.AvailableConnections
}
// ErrAcquireTimeout occurs when an attempt to acquire a connection times out.
var ErrAcquireTimeout = errors.New("timeout acquiring connection from pool")
// ErrClosedPool occurs on an attempt to acquire a connection from a closed pool.
var ErrClosedPool = errors.New("cannot acquire from closed pool")
// NewConnPool creates a new ConnPool. config.ConnConfig is passed through to
// Connect directly.
func NewConnPool(config ConnPoolConfig) (p *ConnPool, err error) {
p = new(ConnPool)
p.config = config.ConnConfig
p.connInfo = minimalConnInfo
p.maxConnections = config.MaxConnections
if p.maxConnections == 0 {
p.maxConnections = 5
}
if p.maxConnections < 1 {
return nil, errors.New("MaxConnections must be at least 1")
}
p.acquireTimeout = config.AcquireTimeout
if p.acquireTimeout < 0 {
return nil, errors.New("AcquireTimeout must be equal to or greater than 0")
}
p.afterConnect = config.AfterConnect
if config.LogLevel != 0 {
p.logLevel = config.LogLevel
} else {
// Preserve pre-LogLevel behavior by defaulting to LogLevelDebug
p.logLevel = LogLevelDebug
}
p.logger = config.Logger
if p.logger == nil {
p.logLevel = LogLevelNone
}
p.allConnections = make([]*Conn, 0, p.maxConnections)
p.availableConnections = make([]*Conn, 0, p.maxConnections)
p.preparedStatements = make(map[string]*PreparedStatement)
p.cond = sync.NewCond(new(sync.Mutex))
// Initially establish one connection
var c *Conn
c, err = p.createConnection()
if err != nil {
return
}
p.allConnections = append(p.allConnections, c)
p.availableConnections = append(p.availableConnections, c)
p.connInfo = c.ConnInfo.DeepCopy()
return
}
// Acquire takes exclusive use of a connection until it is released.
func (p *ConnPool) Acquire() (*Conn, error) {
p.cond.L.Lock()
c, err := p.acquire(nil)
p.cond.L.Unlock()
return c, err
}
// deadlinePassed returns true if the given deadline has passed.
func (p *ConnPool) deadlinePassed(deadline *time.Time) bool {
return deadline != nil && time.Now().After(*deadline)
}
// acquire performs acquision assuming pool is already locked
func (p *ConnPool) acquire(deadline *time.Time) (*Conn, error) {
if p.closed {
return nil, ErrClosedPool
}
// A connection is available
// The pool works like a queue. Available connection will be returned
// from the head. A new connection will be added to the tail.
numAvailable := len(p.availableConnections)
if numAvailable > 0 {
c := p.availableConnections[0]
c.poolResetCount = p.resetCount
copy(p.availableConnections, p.availableConnections[1:])
p.availableConnections = p.availableConnections[:numAvailable-1]
return c, nil
}
// Set initial timeout/deadline value. If the method (acquire) happens to
// recursively call itself the deadline should retain its value.
if deadline == nil && p.acquireTimeout > 0 {
tmp := time.Now().Add(p.acquireTimeout)
deadline = &tmp
}
// Make sure the deadline (if it is) has not passed yet
if p.deadlinePassed(deadline) {
return nil, ErrAcquireTimeout
}
// If there is a deadline then start a timeout timer
var timer *time.Timer
if deadline != nil {
timer = time.AfterFunc(deadline.Sub(time.Now()), func() {
p.cond.Broadcast()
})
defer timer.Stop()
}
// No connections are available, but we can create more
if len(p.allConnections)+p.inProgressConnects < p.maxConnections {
// Create a new connection.
// Careful here: createConnectionUnlocked() removes the current lock,
// creates a connection and then locks it back.
c, err := p.createConnectionUnlocked()
if err != nil {
return nil, err
}
c.poolResetCount = p.resetCount
p.allConnections = append(p.allConnections, c)
return c, nil
}
// All connections are in use and we cannot create more
if p.logLevel >= LogLevelWarn {
p.logger.Log(LogLevelWarn, "waiting for available connection", nil)
}
// Wait until there is an available connection OR room to create a new connection
for len(p.availableConnections) == 0 && len(p.allConnections)+p.inProgressConnects == p.maxConnections {
if p.deadlinePassed(deadline) {
return nil, ErrAcquireTimeout
}
p.cond.Wait()
}
// Stop the timer so that we do not spawn it on every acquire call.
if timer != nil {
timer.Stop()
}
return p.acquire(deadline)
}
// Release gives up use of a connection.
func (p *ConnPool) Release(conn *Conn) {
if conn.ctxInProgress {
panic("should never release when context is in progress")
}
if conn.pgConn.TxStatus != 'I' {
conn.Exec(context.TODO(), "rollback")
}
if len(conn.channels) > 0 {
if err := conn.Unlisten("*"); err != nil {
conn.die(err)
}
conn.channels = make(map[string]struct{})
}
p.cond.L.Lock()
if conn.poolResetCount != p.resetCount {
conn.Close()
p.cond.L.Unlock()
p.cond.Signal()
return
}
if conn.IsAlive() {
p.availableConnections = append(p.availableConnections, conn)
} else {
p.removeFromAllConnections(conn)
}
p.cond.L.Unlock()
p.cond.Signal()
}
// removeFromAllConnections Removes the given connection from the list.
// It returns true if the connection was found and removed or false otherwise.
func (p *ConnPool) removeFromAllConnections(conn *Conn) bool {
for i, c := range p.allConnections {
if conn == c {
p.allConnections = append(p.allConnections[:i], p.allConnections[i+1:]...)
return true
}
}
return false
}
// Close ends the use of a connection pool. It prevents any new connections from
// being acquired and closes available underlying connections. Any acquired
// connections will be closed when they are released.
func (p *ConnPool) Close() {
p.cond.L.Lock()
defer p.cond.L.Unlock()
p.closed = true
for _, c := range p.availableConnections {
_ = c.Close()
}
// This will cause any checked out connections to be closed on release
p.resetCount++
}
// Reset closes all open connections, but leaves the pool open. It is intended
// for use when an error is detected that would disrupt all connections (such as
// a network interruption or a server state change).
//
// It is safe to reset a pool while connections are checked out. Those
// connections will be closed when they are returned to the pool.
func (p *ConnPool) Reset() {
p.cond.L.Lock()
defer p.cond.L.Unlock()
p.resetCount++
p.allConnections = p.allConnections[0:0]
for _, conn := range p.availableConnections {
conn.Close()
}
p.availableConnections = p.availableConnections[0:0]
}
// invalidateAcquired causes all acquired connections to be closed when released.
// The pool must already be locked.
func (p *ConnPool) invalidateAcquired() {
p.resetCount++
for _, c := range p.availableConnections {
c.poolResetCount = p.resetCount
}
p.allConnections = p.allConnections[:len(p.availableConnections)]
copy(p.allConnections, p.availableConnections)
}
// Stat returns connection pool statistics
func (p *ConnPool) Stat() (s ConnPoolStat) {
p.cond.L.Lock()
defer p.cond.L.Unlock()
s.MaxConnections = p.maxConnections
s.CurrentConnections = len(p.allConnections)
s.AvailableConnections = len(p.availableConnections)
return
}
func (p *ConnPool) createConnection() (*Conn, error) {
c, err := connect(context.TODO(), &p.config, p.connInfo)
if err != nil {
return nil, err
}
return p.afterConnectionCreated(c)
}
// createConnectionUnlocked Removes the current lock, creates a new connection, and
// then locks it back.
// Here is the point: lets say our pool dialer's OpenTimeout is set to 3 seconds.
// And we have a pool with 20 connections in it, and we try to acquire them all at
// startup.
// If it happens that the remote server is not accessible, then the first connection
// in the pool blocks all the others for 3 secs, before it gets the timeout. Then
// connection #2 holds the lock and locks everything for the next 3 secs until it
// gets OpenTimeout err, etc. And the very last 20th connection will fail only after
// 3 * 20 = 60 secs.
// To avoid this we put Connect(p.config) outside of the lock (it is thread safe)
// what would allow us to make all the 20 connection in parallel (more or less).
func (p *ConnPool) createConnectionUnlocked() (*Conn, error) {
p.inProgressConnects++
p.cond.L.Unlock()
// c, err := Connect(p.config)
c, err := Connect(context.TODO(), "TODO")
p.cond.L.Lock()
p.inProgressConnects--
if err != nil {
return nil, err
}
return p.afterConnectionCreated(c)
}
// afterConnectionCreated executes (if it is) afterConnect() callback and prepares
// all the known statements for the new connection.
func (p *ConnPool) afterConnectionCreated(c *Conn) (*Conn, error) {
if p.afterConnect != nil {
err := p.afterConnect(c)
if err != nil {
c.die(err)
return nil, err
}
}
for _, ps := range p.preparedStatements {
if _, err := c.Prepare(ps.Name, ps.SQL); err != nil {
c.die(err)
return nil, err
}
}
return c, nil
}
// Exec acquires a connection, delegates the call to that connection, and releases the connection
func (p *ConnPool) Exec(ctx context.Context, sql string, arguments ...interface{}) (commandTag pgconn.CommandTag, err error) {
var c *Conn
if c, err = p.Acquire(); err != nil {
return
}
defer p.Release(c)
return c.Exec(ctx, sql, arguments...)
}
// Query acquires a connection and delegates the call to that connection. When
// *Rows are closed, the connection is released automatically.
func (p *ConnPool) Query(sql string, args ...interface{}) (*Rows, error) {
c, err := p.Acquire()
if err != nil {
// Because checking for errors can be deferred to the *Rows, build one with the error
return &Rows{closed: true, err: err}, err
}
rows, err := c.Query(sql, args...)
if err != nil {
p.Release(c)
return rows, err
}
rows.connPool = p
return rows, nil
}
func (p *ConnPool) QueryEx(ctx context.Context, sql string, options *QueryExOptions, args ...interface{}) (*Rows, error) {
c, err := p.Acquire()
if err != nil {
// Because checking for errors can be deferred to the *Rows, build one with the error
return &Rows{closed: true, err: err}, err
}
rows, err := c.QueryEx(ctx, sql, options, args...)
if err != nil {
p.Release(c)
return rows, err
}
rows.connPool = p
return rows, nil
}
// QueryRow acquires a connection and delegates the call to that connection. The
// connection is released automatically after Scan is called on the returned
// *Row.
func (p *ConnPool) QueryRow(sql string, args ...interface{}) *Row {
rows, _ := p.Query(sql, args...)
return (*Row)(rows)
}
func (p *ConnPool) QueryRowEx(ctx context.Context, sql string, options *QueryExOptions, args ...interface{}) *Row {
rows, _ := p.QueryEx(ctx, sql, options, args...)
return (*Row)(rows)
}
// Begin acquires a connection and begins a transaction on it. When the
// transaction is closed the connection will be automatically released.
func (p *ConnPool) Begin() (*Tx, error) {
return p.BeginEx(context.Background(), nil)
}
// Prepare creates a prepared statement on a connection in the pool to test the
// statement is valid. If it succeeds all connections accessed through the pool
// will have the statement available.
//
// Prepare creates a prepared statement with name and sql. sql can contain
// placeholders for bound parameters. These placeholders are referenced
// positional as $1, $2, etc.
//
// Prepare is idempotent; i.e. it is safe to call Prepare multiple times with
// the same name and sql arguments. This allows a code path to Prepare and
// Query/Exec/PrepareEx without concern for if the statement has already been prepared.
func (p *ConnPool) Prepare(name, sql string) (*PreparedStatement, error) {
return p.PrepareEx(context.Background(), name, sql, nil)
}
// PrepareEx creates a prepared statement on a connection in the pool to test the
// statement is valid. If it succeeds all connections accessed through the pool
// will have the statement available.
//
// PrepareEx creates a prepared statement with name and sql. sql can contain placeholders
// for bound parameters. These placeholders are referenced positional as $1, $2, etc.
// It differs from Prepare as it allows additional options (such as parameter OIDs) to be passed via struct
//
// PrepareEx is idempotent; i.e. it is safe to call PrepareEx multiple times with the same
// name and sql arguments. This allows a code path to PrepareEx and Query/Exec/Prepare without
// concern for if the statement has already been prepared.
func (p *ConnPool) PrepareEx(ctx context.Context, name, sql string, opts *PrepareExOptions) (*PreparedStatement, error) {
p.cond.L.Lock()
defer p.cond.L.Unlock()
if ps, ok := p.preparedStatements[name]; ok && ps.SQL == sql {
return ps, nil
}
c, err := p.acquire(nil)
if err != nil {
return nil, err
}
p.availableConnections = append(p.availableConnections, c)
// Double check that the statement was not prepared by someone else
// while we were acquiring the connection (since acquire is not fully
// blocking now, see createConnectionUnlocked())
if ps, ok := p.preparedStatements[name]; ok && ps.SQL == sql {
return ps, nil
}
ps, err := c.PrepareEx(ctx, name, sql, opts)
if err != nil {
return nil, err
}
for _, c := range p.availableConnections {
_, err := c.PrepareEx(ctx, name, sql, opts)
if err != nil {
return nil, err
}
}
p.invalidateAcquired()
p.preparedStatements[name] = ps
return ps, err
}
// Deallocate releases a prepared statement from all connections in the pool.
func (p *ConnPool) Deallocate(name string) (err error) {
p.cond.L.Lock()
defer p.cond.L.Unlock()
for _, c := range p.availableConnections {
if err := c.Deallocate(name); err != nil {
return err
}
}
p.invalidateAcquired()
delete(p.preparedStatements, name)
return nil
}
// BeginEx acquires a connection and starts a transaction with txOptions
// determining the transaction mode. When the transaction is closed the
// connection will be automatically released.
func (p *ConnPool) BeginEx(ctx context.Context, txOptions *TxOptions) (*Tx, error) {
for {
c, err := p.Acquire()
if err != nil {
return nil, err
}
tx, err := c.BeginEx(ctx, txOptions)
if err != nil {
alive := c.IsAlive()
p.Release(c)
// If connection is still alive then the error is not something trying
// again on a new connection would fix, so just return the error. But
// if the connection is dead try to acquire a new connection and try
// again.
if alive || ctx.Err() != nil {
return nil, err
}
continue
}
tx.connPool = p
return tx, nil
}
}
// CopyFrom acquires a connection, delegates the call to that connection, and releases the connection
func (p *ConnPool) CopyFrom(tableName Identifier, columnNames []string, rowSrc CopyFromSource) (int, error) {
c, err := p.Acquire()
if err != nil {
return 0, err
}
defer p.Release(c)
return c.CopyFrom(tableName, columnNames, rowSrc)
}
// BeginBatch acquires a connection and begins a batch on that connection. When
// *Batch is finished, the connection is released automatically.
func (p *ConnPool) BeginBatch() *Batch {
c, err := p.Acquire()
return &Batch{conn: c, connPool: p, err: err}
}

44
conn_pool_private_test.go
View File

@ -1,44 +0,0 @@
package pgx
import (
"testing"
)
func compareConnSlices(slice1, slice2 []*Conn) bool {
if len(slice1) != len(slice2) {
return false
}
for i, c := range slice1 {
if c != slice2[i] {
return false
}
}
return true
}
func TestConnPoolRemoveFromAllConnections(t *testing.T) {
t.Parallel()
pool := ConnPool{}
conn1 := &Conn{}
conn2 := &Conn{}
conn3 := &Conn{}
// First element
pool.allConnections = []*Conn{conn1, conn2, conn3}
pool.removeFromAllConnections(conn1)
if !compareConnSlices(pool.allConnections, []*Conn{conn2, conn3}) {
t.Fatal("First element test failed")
}
// Element somewhere in the middle
pool.allConnections = []*Conn{conn1, conn2, conn3}
pool.removeFromAllConnections(conn2)
if !compareConnSlices(pool.allConnections, []*Conn{conn1, conn3}) {
t.Fatal("Middle element test failed")
}
// Last element
pool.allConnections = []*Conn{conn1, conn2, conn3}
pool.removeFromAllConnections(conn3)
if !compareConnSlices(pool.allConnections, []*Conn{conn1, conn2}) {
t.Fatal("Last element test failed")
}
}

926
conn_pool_test.go
View File

@ -1,926 +0,0 @@
package pgx_test
import (
"context"
"fmt"
"net"
"os"
"sync"
"testing"
"time"
"github.com/pkg/errors"
"github.com/jackc/pgconn"
"github.com/jackc/pgx"
)
func createConnPool(t *testing.T, maxConnections int) *pgx.ConnPool {
config := pgx.ConnPoolConfig{ConnConfig: mustParseConfig(t, os.Getenv("PGX_TEST_DATABASE")), MaxConnections: maxConnections}
pool, err := pgx.NewConnPool(config)
if err != nil {
t.Fatalf("Unable to create connection pool: %v", err)
}
return pool
}
func acquireAllConnections(t *testing.T, pool *pgx.ConnPool, maxConnections int) []*pgx.Conn {
connections := make([]*pgx.Conn, maxConnections)
for i := 0; i < maxConnections; i++ {
var err error
if connections[i], err = pool.Acquire(); err != nil {
t.Fatalf("Unable to acquire connection: %v", err)
}
}
return connections
}
func releaseAllConnections(pool *pgx.ConnPool, connections []*pgx.Conn) {
for _, c := range connections {
pool.Release(c)
}
}
func acquireWithTimeTaken(pool *pgx.ConnPool) (*pgx.Conn, time.Duration, error) {
startTime := time.Now()
c, err := pool.Acquire()
return c, time.Since(startTime), err
}
func TestNewConnPool(t *testing.T) {
t.Parallel()
var numCallbacks int
afterConnect := func(c *pgx.Conn) error {
numCallbacks++
return nil
}
config := pgx.ConnPoolConfig{ConnConfig: mustParseConfig(t, os.Getenv("PGX_TEST_DATABASE")), MaxConnections: 2, AfterConnect: afterConnect}
pool, err := pgx.NewConnPool(config)
if err != nil {
t.Fatal("Unable to establish connection pool")
}
defer pool.Close()
// It initially connects once
stat := pool.Stat()
if stat.CurrentConnections != 1 {
t.Errorf("Expected 1 connection to be established immediately, but %v were", numCallbacks)
}
// Pool creation returns an error if any AfterConnect callback does
errAfterConnect := errors.New("Some error")
afterConnect = func(c *pgx.Conn) error {
return errAfterConnect
}
config = pgx.ConnPoolConfig{ConnConfig: mustParseConfig(t, os.Getenv("PGX_TEST_DATABASE")), MaxConnections: 2, AfterConnect: afterConnect}
pool, err = pgx.NewConnPool(config)
if err != errAfterConnect {
t.Errorf("Expected errAfterConnect but received unexpected: %v", err)
}
}
func TestNewConnPoolDefaultsTo5MaxConnections(t *testing.T) {
t.Parallel()
config := pgx.ConnPoolConfig{ConnConfig: mustParseConfig(t, os.Getenv("PGX_TEST_DATABASE"))}
pool, err := pgx.NewConnPool(config)
if err != nil {
t.Fatal("Unable to establish connection pool")
}
defer pool.Close()
if n := pool.Stat().MaxConnections; n != 5 {
t.Fatalf("Expected pool to default to 5 max connections, but it was %d", n)
}
}
func TestPoolAcquireAndReleaseCycle(t *testing.T) {
t.Parallel()
maxConnections := 2
incrementCount := int32(100)
completeSync := make(chan int)
pool := createConnPool(t, maxConnections)
defer pool.Close()
allConnections := acquireAllConnections(t, pool, maxConnections)
for _, c := range allConnections {
mustExec(t, c, "create temporary table t(counter integer not null)")
mustExec(t, c, "insert into t(counter) values(0);")
}
releaseAllConnections(pool, allConnections)
f := func() {
conn, err := pool.Acquire()
if err != nil {
t.Fatal("Unable to acquire connection")
}
defer pool.Release(conn)
// Increment counter...
mustExec(t, conn, "update t set counter = counter + 1")
completeSync <- 0
}
for i := int32(0); i < incrementCount; i++ {
go f()
}
// Wait for all f() to complete
for i := int32(0); i < incrementCount; i++ {
<-completeSync
}
// Check that temp table in each connection has been incremented some number of times
actualCount := int32(0)
allConnections = acquireAllConnections(t, pool, maxConnections)
for _, c := range allConnections {
var n int32
c.QueryRow("select counter from t").Scan(&n)
if n == 0 {
t.Error("A connection was never used")
}
actualCount += n
}
if actualCount != incrementCount {
fmt.Println(actualCount)
t.Error("Wrong number of increments")
}
releaseAllConnections(pool, allConnections)
}
func TestPoolNonBlockingConnections(t *testing.T) {
t.Parallel()
var dialCountLock sync.Mutex
dialCount := 0
openTimeout := 1 * time.Second
testDialer := func(ctx context.Context, network, address string) (net.Conn, error) {
var firstDial bool
dialCountLock.Lock()
dialCount++
firstDial = dialCount == 1
dialCountLock.Unlock()
if firstDial {
return net.Dial(network, address)
} else {
time.Sleep(openTimeout)
return nil, &net.OpError{Op: "dial", Net: "tcp"}
}
}
maxConnections := 3
config := pgx.ConnPoolConfig{
ConnConfig: mustParseConfig(t, os.Getenv("PGX_TEST_DATABASE")),
MaxConnections: maxConnections,
}
config.ConnConfig.Config.DialFunc = testDialer
pool, err := pgx.NewConnPool(config)
if err != nil {
t.Fatalf("Expected NewConnPool not to fail, instead it failed with: %v", err)
}
defer pool.Close()
// NewConnPool establishes an initial connection
// so we need to close that for the rest of the test
if conn, err := pool.Acquire(); err == nil {
conn.Close()
pool.Release(conn)
} else {
t.Fatalf("pool.Acquire unexpectedly failed: %v", err)
}
var wg sync.WaitGroup
wg.Add(maxConnections)
startedAt := time.Now()
for i := 0; i < maxConnections; i++ {
go func() {
_, err := pool.Acquire()
wg.Done()
if err == nil {
t.Fatal("Acquire() expected to fail but it did not")
}
}()
}
wg.Wait()
// Prior to createConnectionUnlocked() use the test took
// maxConnections * openTimeout seconds to complete.
// With createConnectionUnlocked() it takes ~ 1 * openTimeout seconds.
timeTaken := time.Since(startedAt)
if timeTaken > openTimeout+1*time.Second {
t.Fatalf("Expected all Acquire() to run in parallel and take about %v, instead it took '%v'", openTimeout, timeTaken)
}
}
func TestPoolErrClosedPool(t *testing.T) {
t.Parallel()
pool := createConnPool(t, 1)
// Intentionaly close the pool now so we can test ErrClosedPool
pool.Close()
c, err := pool.Acquire()
if c != nil {
t.Fatalf("Expected acquired connection to be nil, instead it was '%v'", c)
}
if err == nil || err != pgx.ErrClosedPool {
t.Fatalf("Expected error to be pgx.ErrClosedPool, instead it was '%v'", err)
}
}
func TestPoolAcquireAndReleaseCycleAutoConnect(t *testing.T) {
t.Parallel()
maxConnections := 3
pool := createConnPool(t, maxConnections)
defer pool.Close()
doSomething := func() {
c, err := pool.Acquire()
if err != nil {
t.Fatalf("Unable to Acquire: %v", err)
}
rows, _ := c.Query("select 1, pg_sleep(0.02)")
rows.Close()
pool.Release(c)
}
for i := 0; i < 10; i++ {
doSomething()
}
stat := pool.Stat()
if stat.CurrentConnections != 1 {
t.Fatalf("Pool shouldn't have established more connections when no contention: %v", stat.CurrentConnections)
}
var wg sync.WaitGroup
for i := 0; i < 10; i++ {
wg.Add(1)
go func() {
defer wg.Done()
doSomething()
}()
}
wg.Wait()
stat = pool.Stat()
if stat.CurrentConnections != stat.MaxConnections {
t.Fatalf("Pool should have used all possible connections: %v", stat.CurrentConnections)
}
}
func TestPoolReleaseDiscardsDeadConnections(t *testing.T) {
t.Parallel()
// Run timing sensitive test many times
for i := 0; i < 50; i++ {
func() {
maxConnections := 3
pool := createConnPool(t, maxConnections)
defer pool.Close()
var c1, c2 *pgx.Conn
var err error
var stat pgx.ConnPoolStat
if c1, err = pool.Acquire(); err != nil {
t.Fatalf("Unexpected error acquiring connection: %v", err)
}
defer func() {
if c1 != nil {
pool.Release(c1)
}
}()
if c2, err = pool.Acquire(); err != nil {
t.Fatalf("Unexpected error acquiring connection: %v", err)
}
defer func() {
if c2 != nil {
pool.Release(c2)
}
}()
if _, err = c2.Exec(context.Background(), "select pg_terminate_backend($1)", c1.PID()); err != nil {
t.Fatalf("Unable to kill backend PostgreSQL process: %v", err)
}
// do something with the connection so it knows it's dead
rows, _ := c1.Query("select 1")
rows.Close()
if rows.Err() == nil {
t.Fatal("Expected error but none occurred")
}
if c1.IsAlive() {
t.Fatal("Expected connection to be dead but it wasn't")
}
stat = pool.Stat()
if stat.CurrentConnections != 2 {
t.Fatalf("Unexpected CurrentConnections: %v", stat.CurrentConnections)
}
if stat.AvailableConnections != 0 {
t.Fatalf("Unexpected AvailableConnections: %v", stat.CurrentConnections)
}
pool.Release(c1)
c1 = nil // so it doesn't get released again by the defer
stat = pool.Stat()
if stat.CurrentConnections != 1 {
t.Fatalf("Unexpected CurrentConnections: %v", stat.CurrentConnections)
}
if stat.AvailableConnections != 0 {
t.Fatalf("Unexpected AvailableConnections: %v", stat.CurrentConnections)
}
}()
}
}
func TestConnPoolResetClosesCheckedOutConnectionsOnRelease(t *testing.T) {
t.Parallel()
pool := createConnPool(t, 5)
defer pool.Close()
inProgressRows := []*pgx.Rows{}
var inProgressPIDs []int32
// Start some queries and reset pool while they are in progress
for i := 0; i < 10; i++ {
rows, err := pool.Query("select pg_backend_pid() union all select 1 union all select 2")
if err != nil {
t.Fatal(err)
}
rows.Next()
var pid int32
rows.Scan(&pid)
inProgressPIDs = append(inProgressPIDs, pid)
inProgressRows = append(inProgressRows, rows)
pool.Reset()
}
// Check that the queries are completed
for _, rows := range inProgressRows {
var expectedN int32
for rows.Next() {
expectedN++
var n int32
err := rows.Scan(&n)
if err != nil {
t.Fatal(err)
}
if expectedN != n {
t.Fatalf("Expected n to be %d, but it was %d", expectedN, n)
}
}
if err := rows.Err(); err != nil {
t.Fatal(err)
}
}
// pool should be in fresh state due to previous reset
stats := pool.Stat()
if stats.CurrentConnections != 0 || stats.AvailableConnections != 0 {
t.Fatalf("Unexpected connection pool stats: %v", stats)
}
var connCount int
err := pool.QueryRow("select count(*) from pg_stat_activity where pid = any($1::int4[])", inProgressPIDs).Scan(&connCount)
if err != nil {
t.Fatal(err)
}
if connCount != 0 {
t.Fatalf("%d connections not closed", connCount)
}
}
func TestConnPoolResetClosesCheckedInConnections(t *testing.T) {
t.Parallel()
pool := createConnPool(t, 5)
defer pool.Close()
inProgressRows := []*pgx.Rows{}
var inProgressPIDs []int32
// Start some queries and reset pool while they are in progress
for i := 0; i < 5; i++ {
rows, err := pool.Query("select pg_backend_pid()")
if err != nil {
t.Fatal(err)
}
inProgressRows = append(inProgressRows, rows)
}
// Check that the queries are completed
for _, rows := range inProgressRows {
for rows.Next() {
var pid int32
err := rows.Scan(&pid)
if err != nil {
t.Fatal(err)
}
inProgressPIDs = append(inProgressPIDs, pid)
}
if err := rows.Err(); err != nil {
t.Fatal(err)
}
}
// Ensure pool is fully connected and available
stats := pool.Stat()
if stats.CurrentConnections != 5 || stats.AvailableConnections != 5 {
t.Fatalf("Unexpected connection pool stats: %v", stats)
}
pool.Reset()
// Pool should be empty after reset
stats = pool.Stat()
if stats.CurrentConnections != 0 || stats.AvailableConnections != 0 {
t.Fatalf("Unexpected connection pool stats: %v", stats)
}
var connCount int
err := pool.QueryRow("select count(*) from pg_stat_activity where pid = any($1::int4[])", inProgressPIDs).Scan(&connCount)
if err != nil {
t.Fatal(err)
}
if connCount != 0 {
t.Fatalf("%d connections not closed", connCount)
}
}
func TestConnPoolTransaction(t *testing.T) {
t.Parallel()
pool := createConnPool(t, 2)
defer pool.Close()
stats := pool.Stat()
if stats.CurrentConnections != 1 || stats.AvailableConnections != 1 {
t.Fatalf("Unexpected connection pool stats: %v", stats)
}
tx, err := pool.Begin()
if err != nil {
t.Fatalf("pool.Begin failed: %v", err)
}
defer tx.Rollback()
var n int32
err = tx.QueryRow("select 40+$1", 2).Scan(&n)
if err != nil {
t.Fatalf("tx.QueryRow Scan failed: %v", err)
}
if n != 42 {
t.Errorf("Expected 42, got %d", n)
}
stats = pool.Stat()
if stats.CurrentConnections != 1 || stats.AvailableConnections != 0 {
t.Fatalf("Unexpected connection pool stats: %v", stats)
}
err = tx.Rollback()
if err != nil {
t.Fatalf("tx.Rollback failed: %v", err)
}
stats = pool.Stat()
if stats.CurrentConnections != 1 || stats.AvailableConnections != 1 {
t.Fatalf("Unexpected connection pool stats: %v", stats)
}
}
func TestConnPoolTransactionIso(t *testing.T) {
t.Parallel()
pool := createConnPool(t, 2)
defer pool.Close()
tx, err := pool.BeginEx(context.Background(), &pgx.TxOptions{IsoLevel: pgx.Serializable})
if err != nil {
t.Fatalf("pool.BeginEx failed: %v", err)
}
defer tx.Rollback()
var level string
err = tx.QueryRow("select current_setting('transaction_isolation')").Scan(&level)
if err != nil {
t.Fatalf("tx.QueryRow failed: %v", level)
}
if level != "serializable" {
t.Errorf("Expected to be in isolation level %v but was %v", "serializable", level)
}
}
func TestConnPoolBeginRetry(t *testing.T) {
t.Parallel()
// Run timing sensitive test many times
for i := 0; i < 50; i++ {
func() {
pool := createConnPool(t, 2)
defer pool.Close()
killerConn, err := pool.Acquire()
if err != nil {
t.Fatal(err)
}
defer pool.Release(killerConn)
victimConn, err := pool.Acquire()
if err != nil {
t.Fatal(err)
}
pool.Release(victimConn)
// Terminate connection that was released to pool
if _, err = killerConn.Exec(context.Background(), "select pg_terminate_backend($1)", victimConn.PID()); err != nil {
t.Fatalf("Unable to kill backend PostgreSQL process: %v", err)
}
// Since victimConn is the only available connection in the pool, pool.Begin should
// try to use it, fail, and allocate another connection
tx, err := pool.Begin()
if err != nil {
t.Fatalf("pool.Begin failed: %v", err)
}
defer tx.Rollback()
var txPID uint32
err = tx.QueryRow("select pg_backend_pid()").Scan(&txPID)
if err != nil {
t.Fatalf("tx.QueryRow Scan failed: %v", err)
}
if txPID == victimConn.PID() {
t.Error("Expected txPID to defer from killed conn pid, but it didn't")
}
}()
}
}
func TestConnPoolQuery(t *testing.T) {
t.Parallel()
pool := createConnPool(t, 2)
defer pool.Close()
var sum, rowCount int32
rows, err := pool.Query("select generate_series(1,$1)", 10)
if err != nil {
t.Fatalf("pool.Query failed: %v", err)
}
stats := pool.Stat()
if stats.CurrentConnections != 1 || stats.AvailableConnections != 0 {
t.Fatalf("Unexpected connection pool stats: %v", stats)
}
for rows.Next() {
var n int32
rows.Scan(&n)
sum += n
rowCount++
}
if rows.Err() != nil {
t.Fatalf("conn.Query failed: %v", err)
}
if rowCount != 10 {
t.Error("Select called onDataRow wrong number of times")
}
if sum != 55 {
t.Error("Wrong values returned")
}
stats = pool.Stat()
if stats.CurrentConnections != 1 || stats.AvailableConnections != 1 {
t.Fatalf("Unexpected connection pool stats: %v", stats)
}
}
func TestConnPoolQueryConcurrentLoad(t *testing.T) {
t.Parallel()
pool := createConnPool(t, 10)
defer pool.Close()
n := 100
done := make(chan bool)
for i := 0; i < n; i++ {
go func() {
defer func() { done <- true }()
var rowCount int32
rows, err := pool.Query("select generate_series(1,$1)", 1000)
if err != nil {
t.Fatalf("pool.Query failed: %v", err)
}
defer rows.Close()
for rows.Next() {
var n int32
err = rows.Scan(&n)
if err != nil {
t.Fatalf("rows.Scan failed: %v", err)
}
if n != rowCount+1 {
t.Fatalf("Expected n to be %d, but it was %d", rowCount+1, n)
}
rowCount++
}
if rows.Err() != nil {
t.Fatalf("conn.Query failed: %v", rows.Err())
}
if rowCount != 1000 {
t.Error("Select called onDataRow wrong number of times")
}
_, err = pool.Exec(context.Background(), "--;")
if err != nil {
t.Fatalf("pool.Exec failed: %v", err)
}
}()
}
for i := 0; i < n; i++ {
<-done
}
}
func TestConnPoolQueryRow(t *testing.T) {
t.Parallel()
pool := createConnPool(t, 2)
defer pool.Close()
var n int32
err := pool.QueryRow("select 40+$1", 2).Scan(&n)
if err != nil {
t.Fatalf("pool.QueryRow Scan failed: %v", err)
}
if n != 42 {
t.Errorf("Expected 42, got %d", n)
}
stats := pool.Stat()
if stats.CurrentConnections != 1 || stats.AvailableConnections != 1 {
t.Fatalf("Unexpected connection pool stats: %v", stats)
}
}
func TestConnPoolPrepare(t *testing.T) {
t.Parallel()
pool := createConnPool(t, 2)
defer pool.Close()
_, err := pool.Prepare("test", "select $1::varchar")
if err != nil {
t.Fatalf("Unable to prepare statement: %v", err)
}
var s string
err = pool.QueryRow("test", "hello").Scan(&s)
if err != nil {
t.Errorf("Executing prepared statement failed: %v", err)
}
if s != "hello" {
t.Errorf("Prepared statement did not return expected value: %v", s)
}
err = pool.Deallocate("test")
if err != nil {
t.Errorf("Deallocate failed: %v", err)
}
err = pool.QueryRow("test", "hello").Scan(&s)
if err, ok := err.(*pgconn.PgError); !(ok && err.Code == "42601") {
t.Errorf("Expected error calling deallocated prepared statement, but got: %v", err)
}
}
func TestConnPoolPrepareDeallocatePrepare(t *testing.T) {
t.Parallel()
pool := createConnPool(t, 2)
defer pool.Close()
_, err := pool.Prepare("test", "select $1::varchar")
if err != nil {
t.Fatalf("Unable to prepare statement: %v", err)
}
err = pool.Deallocate("test")
if err != nil {
t.Fatalf("Unable to deallocate statement: %v", err)
}
_, err = pool.Prepare("test", "select $1::varchar")
if err != nil {
t.Fatalf("Unable to prepare statement: %v", err)
}
var s string
err = pool.QueryRow("test", "hello").Scan(&s)
if err != nil {
t.Fatalf("Executing prepared statement failed: %v", err)
}
if s != "hello" {
t.Errorf("Prepared statement did not return expected value: %v", s)
}
}
func TestConnPoolPrepareWhenConnIsAlreadyAcquired(t *testing.T) {
t.Parallel()
t.Skip("TODO")
// pool := createConnPool(t, 2)
// defer pool.Close()
// testPreparedStatement := func(db queryRower, desc string) {
// var s string
// err := db.QueryRow("test", "hello").Scan(&s)
// if err != nil {
// t.Fatalf("%s. Executing prepared statement failed: %v", desc, err)
// }
// if s != "hello" {
// t.Fatalf("%s. Prepared statement did not return expected value: %v", desc, s)
// }
// }
// newReleaseOnce := func(c *pgx.Conn) func() {
// var once sync.Once
// return func() {
// once.Do(func() { pool.Release(c) })
// }
// }
// c1, err := pool.Acquire()
// if err != nil {
// t.Fatalf("Unable to acquire connection: %v", err)
// }
// c1Release := newReleaseOnce(c1)
// defer c1Release()
// _, err = pool.Prepare("test", "select $1::varchar")
// if err != nil {
// t.Fatalf("Unable to prepare statement: %v", err)
// }
// testPreparedStatement(pool, "pool")
// c1Release()
// c2, err := pool.Acquire()
// if err != nil {
// t.Fatalf("Unable to acquire connection: %v", err)
// }
// c2Release := newReleaseOnce(c2)
// defer c2Release()
// // This conn will not be available and will be connection at this point
// c3, err := pool.Acquire()
// if err != nil {
// t.Fatalf("Unable to acquire connection: %v", err)
// }
// c3Release := newReleaseOnce(c3)
// defer c3Release()
// testPreparedStatement(c2, "c2")
// testPreparedStatement(c3, "c3")
// c2Release()
// c3Release()
// err = pool.Deallocate("test")
// if err != nil {
// t.Errorf("Deallocate failed: %v", err)
// }
// var s string
// err = pool.QueryRow("test", "hello").Scan(&s)
// if err, ok := err.(*pgconn.PgError); !(ok && err.Code == "42601") {
// t.Errorf("Expected error calling deallocated prepared statement, but got: %v", err)
// }
}
func TestConnPoolBeginBatch(t *testing.T) {
t.Parallel()
t.Skip("TODO")
// pool := createConnPool(t, 2)
// defer pool.Close()
// batch := pool.BeginBatch()
// batch.Queue("select n from generate_series(0,5) n",
// nil,
// nil,
// []int16{pgx.BinaryFormatCode},
// )
// batch.Queue("select n from generate_series(0,5) n",
// nil,
// nil,
// []int16{pgx.BinaryFormatCode},
// )
// err := batch.Send(context.Background(), nil)
// if err != nil {
// t.Fatal(err)
// }
// rows, err := batch.QueryResults()
// if err != nil {
// t.Error(err)
// }
// for i := 0; rows.Next(); i++ {
// var n int
// if err := rows.Scan(&n); err != nil {
// t.Error(err)
// }
// if n != i {
// t.Errorf("n => %v, want %v", n, i)
// }
// }
// if rows.Err() != nil {
// t.Error(rows.Err())
// }
// rows, err = batch.QueryResults()
// if err != nil {
// t.Error(err)
// }
// for i := 0; rows.Next(); i++ {
// var n int
// if err := rows.Scan(&n); err != nil {
// t.Error(err)
// }
// if n != i {
// t.Errorf("n => %v, want %v", n, i)
// }
// }
// if rows.Err() != nil {
// t.Error(rows.Err())
// }
// err = batch.Close()
// if err != nil {
// t.Fatal(err)
// }
}
func TestConnPoolBeginEx(t *testing.T) {
t.Parallel()
pool := createConnPool(t, 2)
defer pool.Close()
ctx, cancel := context.WithCancel(context.Background())
cancel()
tx, err := pool.BeginEx(ctx, nil)
if err == nil || tx != nil {
t.Fatal("Should not be able to create a tx")
}
}

23
pool/pool_test.go
View File

@ -209,3 +209,26 @@ func TestConnReleaseDestroysClosedConn(t *testing.T) {
assert.Equal(t, 0, pool.Stat().TotalConns()) assert.Equal(t, 0, pool.Stat().TotalConns())
} }
func TestConnPoolQueryConcurrentLoad(t *testing.T) {
pool, err := pool.Connect(context.Background(), os.Getenv("PGX_TEST_DATABASE"))
require.NoError(t, err)
defer pool.Close()
n := 100
done := make(chan bool)
for i := 0; i < n; i++ {
go func() {
defer func() { done <- true }()
testQuery(t, pool)
testQueryEx(t, pool)
testQueryRow(t, pool)
testQueryRowEx(t, pool)
}()
}
for i := 0; i < n; i++ {
<-done
}
}

5
query.go
View File

@ -44,7 +44,6 @@ func (r *Row) Scan(dest ...interface{}) (err error) {
// calling Next() until it returns false, or when a fatal error occurs. // calling Next() until it returns false, or when a fatal error occurs.
type Rows struct { type Rows struct {
conn *Conn conn *Conn
connPool *ConnPool
batch *Batch batch *Batch
values [][]byte values [][]byte
fields []FieldDescription fields []FieldDescription
@ -105,10 +104,6 @@ func (rows *Rows) Close() {
if rows.batch != nil && rows.err != nil { if rows.batch != nil && rows.err != nil {
rows.batch.die(rows.err) rows.batch.die(rows.err)
} }
if rows.connPool != nil {
rows.connPool.Release(rows.conn)
}
} }
func (rows *Rows) Err() error { func (rows *Rows) Err() error {

15
tx.go
View File

@ -105,10 +105,9 @@ func (c *Conn) BeginEx(ctx context.Context, txOptions *TxOptions) (*Tx, error) {
// All Tx methods return ErrTxClosed if Commit or Rollback has already been // All Tx methods return ErrTxClosed if Commit or Rollback has already been
// called on the Tx. // called on the Tx.
type Tx struct { type Tx struct {
conn *Conn conn *Conn
connPool *ConnPool err error
err error status int8
status int8
} }
// Commit commits the transaction // Commit commits the transaction
@ -135,10 +134,6 @@ func (tx *Tx) CommitEx(ctx context.Context) error {
tx.conn.die(errors.New("commit failed")) tx.conn.die(errors.New("commit failed"))
} }
if tx.connPool != nil {
tx.connPool.Release(tx.conn)
}
return tx.err return tx.err
} }
@ -167,10 +162,6 @@ func (tx *Tx) RollbackEx(ctx context.Context) error {
tx.conn.die(errors.New("rollback failed")) tx.conn.die(errors.New("rollback failed"))
} }
if tx.connPool != nil {
tx.connPool.Release(tx.conn)
}
return tx.err return tx.err
} }

17
tx_test.go
View File

@ -100,23 +100,26 @@ func TestTxCommitWhenTxBroken(t *testing.T) {
func TestTxCommitSerializationFailure(t *testing.T) { func TestTxCommitSerializationFailure(t *testing.T) {
t.Parallel() t.Parallel()
pool := createConnPool(t, 5) c1 := mustConnectString(t, os.Getenv("PGX_TEST_DATABASE"))
defer pool.Close() defer closeConn(t, c1)
pool.Exec(context.Background(), `drop table if exists tx_serializable_sums`) c2 := mustConnectString(t, os.Getenv("PGX_TEST_DATABASE"))
_, err := pool.Exec(context.Background(), `create table tx_serializable_sums(num integer);`) defer closeConn(t, c2)
c1.Exec(context.Background(), `drop table if exists tx_serializable_sums`)
_, err := c1.Exec(context.Background(), `create table tx_serializable_sums(num integer);`)
if err != nil { if err != nil {
t.Fatalf("Unable to create temporary table: %v", err) t.Fatalf("Unable to create temporary table: %v", err)
} }
defer pool.Exec(context.Background(), `drop table tx_serializable_sums`) defer c1.Exec(context.Background(), `drop table tx_serializable_sums`)
tx1, err := pool.BeginEx(context.Background(), &pgx.TxOptions{IsoLevel: pgx.Serializable}) tx1, err := c1.BeginEx(context.Background(), &pgx.TxOptions{IsoLevel: pgx.Serializable})
if err != nil { if err != nil {
t.Fatalf("BeginEx failed: %v", err) t.Fatalf("BeginEx failed: %v", err)
} }
defer tx1.Rollback() defer tx1.Rollback()
tx2, err := pool.BeginEx(context.Background(), &pgx.TxOptions{IsoLevel: pgx.Serializable}) tx2, err := c2.BeginEx(context.Background(), &pgx.TxOptions{IsoLevel: pgx.Serializable})
if err != nil { if err != nil {
t.Fatalf("BeginEx failed: %v", err) t.Fatalf("BeginEx failed: %v", err)
} }