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session.go
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session.go
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// Copyright (c) 2012 The gocql Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package gocql
import (
"bytes"
"context"
"encoding/binary"
"errors"
"fmt"
"io"
"net"
"strings"
"sync"
"sync/atomic"
"time"
"unicode"
"github.com/gocql/gocql/internal/lru"
"github.com/gocql/gocql/internal/murmur"
)
// Session is the interface used by users to interact with the database.
//
// It's safe for concurrent use by multiple goroutines and a typical usage
// scenario is to have one global session object to interact with the
// whole Cassandra cluster.
//
// This type extends the Node interface by adding a convenient query builder
// and automatically sets a default consistency level on all operations
// that do not have a consistency level set.
type Session struct {
cons Consistency
pageSize int
prefetch float64
routingKeyInfoCache routingKeyInfoLRU
schemaDescriber *schemaDescriber
trace Tracer
queryObserver QueryObserver
batchObserver BatchObserver
connectObserver ConnectObserver
disconnectObserver DisconnectObserver
frameHeaderObserver FrameHeaderObserver
frameObserver FrameObserver
streamObserver StreamObserver
hostSource *ringDescriber
ringRefresher *refreshDebouncer
stmtsLRU *preparedLRU
connCfg *ConnConfig
executor *queryExecutor
pool *policyConnPool
policy HostSelectionPolicy
ring ring
metadata clusterMetadata
mu sync.RWMutex
control *controlConn
// event handlers
nodeEvents *eventDebouncer
schemaEvents *eventDebouncer
// ring metadata
useSystemSchema bool
hasAggregatesAndFunctions bool
cfg ClusterConfig
ctx context.Context
cancel context.CancelFunc
// sessionStateMu protects isClosed and isInitialized.
sessionStateMu sync.RWMutex
// isClosed is true once Session.Close is finished.
isClosed bool
// isClosing bool is true once Session.Close is started.
isClosing bool
// isInitialized is true once Session.init succeeds.
// you can use initialized() to read the value.
isInitialized bool
logger StdLogger
}
var queryPool = &sync.Pool{
New: func() interface{} {
return &Query{routingInfo: &queryRoutingInfo{}, refCount: 1}
},
}
func addrsToHosts(addrs []string, defaultPort int, logger StdLogger) ([]*HostInfo, error) {
var hosts []*HostInfo
for _, hostaddr := range addrs {
resolvedHosts, err := hostInfo(hostaddr, defaultPort)
if err != nil {
// Try other hosts if unable to resolve DNS name
if _, ok := err.(*net.DNSError); ok {
logger.Printf("gocql: dns error: %v\n", err)
continue
}
return nil, err
}
hosts = append(hosts, resolvedHosts...)
}
if len(hosts) == 0 {
return nil, errors.New("failed to resolve any of the provided hostnames")
}
return hosts, nil
}
// NewSession wraps an existing Node.
func NewSession(cfg ClusterConfig) (*Session, error) {
// Check that hosts in the ClusterConfig is not empty
if len(cfg.Hosts) < 1 {
return nil, ErrNoHosts
}
// Check that either Authenticator is set or AuthProvider, not both
if cfg.Authenticator != nil && cfg.AuthProvider != nil {
return nil, errors.New("Can't use both Authenticator and AuthProvider in cluster config.")
}
// TODO: we should take a context in here at some point
ctx, cancel := context.WithCancel(context.TODO())
s := &Session{
cons: cfg.Consistency,
prefetch: 0.25,
cfg: cfg,
pageSize: cfg.PageSize,
stmtsLRU: &preparedLRU{lru: lru.New(cfg.MaxPreparedStmts)},
connectObserver: cfg.ConnectObserver,
disconnectObserver: cfg.DisconnectObserver,
ctx: ctx,
cancel: cancel,
logger: cfg.logger(),
}
// Close created resources on error otherwise they'll leak
var err error
defer func() {
if err != nil {
s.Close()
}
}()
s.schemaDescriber = newSchemaDescriber(s)
s.nodeEvents = newEventDebouncer("NodeEvents", s.handleNodeEvent, s.logger)
s.schemaEvents = newEventDebouncer("SchemaEvents", s.handleSchemaEvent, s.logger)
s.routingKeyInfoCache.lru = lru.New(cfg.MaxRoutingKeyInfo)
s.hostSource = &ringDescriber{session: s}
s.ringRefresher = newRefreshDebouncer(ringRefreshDebounceTime, func() error { return refreshRing(s.hostSource) })
if cfg.PoolConfig.HostSelectionPolicy == nil {
cfg.PoolConfig.HostSelectionPolicy = RoundRobinHostPolicy()
}
s.pool = cfg.PoolConfig.buildPool(s)
s.policy = cfg.PoolConfig.HostSelectionPolicy
s.policy.Init(s)
s.executor = &queryExecutor{
pool: s.pool,
policy: cfg.PoolConfig.HostSelectionPolicy,
}
s.queryObserver = cfg.QueryObserver
s.batchObserver = cfg.BatchObserver
s.connectObserver = cfg.ConnectObserver
s.frameHeaderObserver = cfg.FrameHeaderObserver
s.frameObserver = cfg.FrameObserver
s.streamObserver = cfg.StreamObserver
//Check the TLS Config before trying to connect to anything external
connCfg, err := connConfig(&s.cfg)
if err != nil {
//TODO: Return a typed error
return nil, fmt.Errorf("gocql: unable to create session: %v", err)
}
s.connCfg = connCfg
if err = s.init(); err != nil {
if err == ErrNoConnectionsStarted {
//This error used to be generated inside NewSession & returned directly
//Forward it on up to be backwards compatible
return nil, ErrNoConnectionsStarted
} else {
// TODO(zariel): dont wrap this error in fmt.Errorf, return a typed error
return nil, fmt.Errorf("gocql: unable to create session: %v", err)
}
}
return s, nil
}
func (s *Session) init() error {
if s.cfg.disableInit {
return nil
}
hosts, err := addrsToHosts(s.cfg.Hosts, s.cfg.Port, s.logger)
if err != nil {
return err
}
s.ring.endpoints = hosts
if !s.cfg.disableControlConn {
s.control = createControlConn(s)
if s.cfg.ProtoVersion == 0 {
proto, err := s.control.discoverProtocol(hosts)
if err != nil {
return fmt.Errorf("unable to discover protocol version: %v", err)
} else if proto == 0 {
return errors.New("unable to discovery protocol version")
}
// TODO(zariel): we really only need this in 1 place
s.cfg.ProtoVersion = proto
s.connCfg.ProtoVersion = proto
}
if err := s.control.connect(hosts); err != nil {
return err
}
if !s.cfg.DisableInitialHostLookup {
var partitioner string
newHosts, partitioner, err := s.hostSource.GetHosts()
if err != nil {
return err
}
s.policy.SetPartitioner(partitioner)
filteredHosts := make([]*HostInfo, 0, len(newHosts))
for _, host := range newHosts {
if !s.cfg.filterHost(host) {
filteredHosts = append(filteredHosts, host)
}
}
hosts = filteredHosts
}
}
for _, host := range hosts {
// In case when host lookup is disabled and when we are in unit tests,
// host are not discovered, and we are missing host ID information used
// by internal logic.
// Associate random UUIDs here with all hosts missing this information.
if len(host.HostID()) == 0 {
host.SetHostID(MustRandomUUID().String())
}
}
hostMap := make(map[string]*HostInfo, len(hosts))
for _, host := range hosts {
hostMap[host.HostID()] = host
}
hosts = hosts[:0]
// each host will increment left and decrement it after connecting and once
// there's none left, we'll close hostCh
var left int64
// we will receive up to len(hostMap) of messages so create a buffer so we
// don't end up stuck in a goroutine if we stopped listening
connectedCh := make(chan struct{}, len(hostMap))
// we add one here because we don't want to end up closing hostCh until we're
// done looping and the decerement code might be reached before we've looped
// again
atomic.AddInt64(&left, 1)
for _, host := range hostMap {
host := s.ring.addOrUpdate(host)
if s.cfg.filterHost(host) {
continue
}
atomic.AddInt64(&left, 1)
go func() {
s.pool.addHost(host)
connectedCh <- struct{}{}
// if there are no hosts left, then close the hostCh to unblock the loop
// below if its still waiting
if atomic.AddInt64(&left, -1) == 0 {
close(connectedCh)
}
}()
hosts = append(hosts, host)
}
// once we're done looping we subtract the one we initially added and check
// to see if we should close
if atomic.AddInt64(&left, -1) == 0 {
close(connectedCh)
}
// before waiting for them to connect, add them all to the policy so we can
// utilize efficiencies by calling AddHosts if the policy supports it
type bulkAddHosts interface {
AddHosts([]*HostInfo)
}
if v, ok := s.policy.(bulkAddHosts); ok {
v.AddHosts(hosts)
} else {
for _, host := range hosts {
s.policy.AddHost(host)
}
}
readyPolicy, _ := s.policy.(ReadyPolicy)
// now loop over connectedCh until it's closed (meaning we've connected to all)
// or until the policy says we're ready
for range connectedCh {
if readyPolicy != nil && readyPolicy.Ready() {
break
}
}
// TODO(zariel): we probably dont need this any more as we verify that we
// can connect to one of the endpoints supplied by using the control conn.
// See if there are any connections in the pool
if s.cfg.ReconnectInterval > 0 {
go s.reconnectDownedHosts(s.cfg.ReconnectInterval)
}
// If we disable the initial host lookup, we need to still check if the
// cluster is using the newer system schema or not... however, if control
// connection is disable, we really have no choice, so we just make our
// best guess...
if !s.cfg.disableControlConn && s.cfg.DisableInitialHostLookup {
newer, _ := checkSystemSchema(s.control)
s.useSystemSchema = newer
} else {
version := s.ring.rrHost().Version()
s.useSystemSchema = version.AtLeast(3, 0, 0)
s.hasAggregatesAndFunctions = version.AtLeast(2, 2, 0)
}
if s.pool.Size() == 0 {
return ErrNoConnectionsStarted
}
// Invoke KeyspaceChanged to let the policy cache the session keyspace
// parameters. This is used by tokenAwareHostPolicy to discover replicas.
if !s.cfg.disableControlConn && s.cfg.Keyspace != "" {
s.policy.KeyspaceChanged(KeyspaceUpdateEvent{Keyspace: s.cfg.Keyspace})
}
s.sessionStateMu.Lock()
s.isInitialized = true
s.sessionStateMu.Unlock()
return nil
}
// AwaitSchemaAgreement will wait until schema versions across all nodes in the
// cluster are the same (as seen from the point of view of the control connection).
// The maximum amount of time this takes is governed
// by the MaxWaitSchemaAgreement setting in the configuration (default: 60s).
// AwaitSchemaAgreement returns an error in case schema versions are not the same
// after the timeout specified in MaxWaitSchemaAgreement elapses.
func (s *Session) AwaitSchemaAgreement(ctx context.Context) error {
if s.cfg.disableControlConn {
return errNoControl
}
return s.control.withConn(func(conn *Conn) *Iter {
return &Iter{err: conn.awaitSchemaAgreement(ctx)}
}).err
}
func (s *Session) reconnectDownedHosts(intv time.Duration) {
reconnectTicker := time.NewTicker(intv)
defer reconnectTicker.Stop()
for {
select {
case <-reconnectTicker.C:
hosts := s.ring.allHosts()
// Print session.ring for debug.
if gocqlDebug {
buf := bytes.NewBufferString("Session.ring:")
for _, h := range hosts {
buf.WriteString("[" + h.ConnectAddress().String() + ":" + h.State().String() + "]")
}
s.logger.Println(buf.String())
}
for _, h := range hosts {
if h.IsUp() {
continue
}
// we let the pool call handleNodeConnected to change the host state
s.pool.addHost(h)
}
case <-s.ctx.Done():
return
}
}
}
// AllHosts returns all hosts currently in the token ring.
func (s *Session) AllHosts() []*HostInfo {
return s.ring.allHosts()
}
// SetConsistency sets the default consistency level for this session. This
// setting can also be changed on a per-query basis and the default value
// is Quorum.
func (s *Session) SetConsistency(cons Consistency) {
s.mu.Lock()
s.cons = cons
s.mu.Unlock()
}
// SetPageSize sets the default page size for this session. A value <= 0 will
// disable paging. This setting can also be changed on a per-query basis.
func (s *Session) SetPageSize(n int) {
s.mu.Lock()
s.pageSize = n
s.mu.Unlock()
}
// SetPrefetch sets the default threshold for pre-fetching new pages. If
// there are only p*pageSize rows remaining, the next page will be requested
// automatically. This value can also be changed on a per-query basis and
// the default value is 0.25.
func (s *Session) SetPrefetch(p float64) {
s.mu.Lock()
s.prefetch = p
s.mu.Unlock()
}
// SetTrace sets the default tracer for this session. This setting can also
// be changed on a per-query basis.
func (s *Session) SetTrace(trace Tracer) {
s.mu.Lock()
s.trace = trace
s.mu.Unlock()
}
// Query generates a new query object for interacting with the database.
// Further details of the query may be tweaked using the resulting query
// value before the query is executed. Query is automatically prepared
// if it has not previously been executed.
func (s *Session) Query(stmt string, values ...interface{}) *Query {
qry := queryPool.Get().(*Query)
qry.session = s
qry.stmt = stmt
qry.values = values
qry.defaultsFromSession()
qry.routingInfo.lwt = false
return qry
}
type QueryInfo struct {
Id []byte
Args []ColumnInfo
Rval []ColumnInfo
PKeyColumns []int
}
// Bind generates a new query object based on the query statement passed in.
// The query is automatically prepared if it has not previously been executed.
// The binding callback allows the application to define which query argument
// values will be marshalled as part of the query execution.
// During execution, the meta data of the prepared query will be routed to the
// binding callback, which is responsible for producing the query argument values.
func (s *Session) Bind(stmt string, b func(q *QueryInfo) ([]interface{}, error)) *Query {
qry := queryPool.Get().(*Query)
qry.session = s
qry.stmt = stmt
qry.binding = b
qry.defaultsFromSession()
qry.routingInfo.lwt = false
return qry
}
// Close closes all connections. The session is unusable after this
// operation.
func (s *Session) Close() {
s.sessionStateMu.Lock()
if s.isClosing {
s.sessionStateMu.Unlock()
return
}
s.isClosing = true
s.sessionStateMu.Unlock()
if s.pool != nil {
s.pool.Close()
}
if s.control != nil {
s.control.close()
}
if s.nodeEvents != nil {
s.nodeEvents.stop()
}
if s.schemaEvents != nil {
s.schemaEvents.stop()
}
if s.ringRefresher != nil {
s.ringRefresher.stop()
}
if s.cancel != nil {
s.cancel()
}
s.sessionStateMu.Lock()
s.isClosed = true
s.sessionStateMu.Unlock()
}
func (s *Session) Closed() bool {
s.sessionStateMu.RLock()
closed := s.isClosed
s.sessionStateMu.RUnlock()
return closed
}
func (s *Session) initialized() bool {
s.sessionStateMu.RLock()
initialized := s.isInitialized
s.sessionStateMu.RUnlock()
return initialized
}
func (s *Session) executeQuery(qry *Query) (it *Iter) {
// fail fast
if s.Closed() {
return &Iter{err: ErrSessionClosed}
}
iter, err := s.executor.executeQuery(qry)
if err != nil {
return &Iter{err: err}
}
if iter == nil {
panic("nil iter")
}
return iter
}
func (s *Session) removeHost(h *HostInfo) {
s.policy.RemoveHost(h)
hostID := h.HostID()
s.pool.removeHost(hostID)
s.ring.removeHost(hostID)
}
// KeyspaceMetadata returns the schema metadata for the keyspace specified. Returns an error if the keyspace does not exist.
func (s *Session) KeyspaceMetadata(keyspace string) (*KeyspaceMetadata, error) {
// fail fast
if s.Closed() {
return nil, ErrSessionClosed
} else if keyspace == "" {
return nil, ErrNoKeyspace
}
return s.schemaDescriber.getSchema(keyspace)
}
func (s *Session) getConn() *Conn {
hosts := s.ring.allHosts()
for _, host := range hosts {
if !host.IsUp() {
continue
}
pool, ok := s.pool.getPool(host)
if !ok {
continue
} else if conn := pool.Pick(nil); conn != nil {
return conn
}
}
return nil
}
// returns routing key indexes and type info
func (s *Session) routingKeyInfo(ctx context.Context, stmt string) (*routingKeyInfo, error) {
s.routingKeyInfoCache.mu.Lock()
entry, cached := s.routingKeyInfoCache.lru.Get(stmt)
if cached {
// done accessing the cache
s.routingKeyInfoCache.mu.Unlock()
// the entry is an inflight struct similar to that used by
// Conn to prepare statements
inflight := entry.(*inflightCachedEntry)
// wait for any inflight work
inflight.wg.Wait()
if inflight.err != nil {
return nil, inflight.err
}
key, _ := inflight.value.(*routingKeyInfo)
return key, nil
}
// create a new inflight entry while the data is created
inflight := new(inflightCachedEntry)
inflight.wg.Add(1)
defer inflight.wg.Done()
s.routingKeyInfoCache.lru.Add(stmt, inflight)
s.routingKeyInfoCache.mu.Unlock()
var (
info *preparedStatment
partitionKey []*ColumnMetadata
)
conn := s.getConn()
if conn == nil {
// TODO: better error?
inflight.err = errors.New("gocql: unable to fetch prepared info: no connection available")
return nil, inflight.err
}
// get the query info for the statement
info, inflight.err = conn.prepareStatement(ctx, stmt, nil)
if inflight.err != nil {
// don't cache this error
s.routingKeyInfoCache.Remove(stmt)
return nil, inflight.err
}
// TODO: it would be nice to mark hosts here but as we are not using the policies
// to fetch hosts we cant
if info.request.colCount == 0 {
// no arguments, no routing key, and no error
return nil, nil
}
table := info.request.table
keyspace := info.request.keyspace
partitioner, err := scyllaGetTablePartitioner(s, keyspace, table)
if err != nil {
// don't cache this error
s.routingKeyInfoCache.Remove(stmt)
return nil, inflight.err
}
if len(info.request.pkeyColumns) > 0 {
// proto v4 dont need to calculate primary key columns
types := make([]TypeInfo, len(info.request.pkeyColumns))
names := make([]string, len(info.request.pkeyColumns))
for i, col := range info.request.pkeyColumns {
types[i] = info.request.columns[col].TypeInfo
names[i] = info.request.columns[col].Name
}
routingKeyInfo := &routingKeyInfo{
indexes: info.request.pkeyColumns,
types: types,
names: names,
lwt: info.request.lwt,
partitioner: partitioner,
keyspace: keyspace,
table: table,
}
inflight.value = routingKeyInfo
return routingKeyInfo, nil
}
// get the table metadata
var keyspaceMetadata *KeyspaceMetadata
keyspaceMetadata, inflight.err = s.KeyspaceMetadata(info.request.columns[0].Keyspace)
if inflight.err != nil {
// don't cache this error
s.routingKeyInfoCache.Remove(stmt)
return nil, inflight.err
}
tableMetadata, found := keyspaceMetadata.Tables[table]
if !found {
// unlikely that the statement could be prepared and the metadata for
// the table couldn't be found, but this may indicate either a bug
// in the metadata code, or that the table was just dropped.
inflight.err = ErrNoMetadata
// don't cache this error
s.routingKeyInfoCache.Remove(stmt)
return nil, inflight.err
}
partitionKey = tableMetadata.PartitionKey
size := len(partitionKey)
routingKeyInfo := &routingKeyInfo{
indexes: make([]int, size),
types: make([]TypeInfo, size),
names: make([]string, size),
lwt: info.request.lwt,
partitioner: partitioner,
keyspace: keyspace,
table: table,
}
for keyIndex, keyColumn := range partitionKey {
// set an indicator for checking if the mapping is missing
routingKeyInfo.indexes[keyIndex] = -1
// find the column in the query info
for argIndex, boundColumn := range info.request.columns {
if keyColumn.Name == boundColumn.Name {
// there may be many such bound columns, pick the first
routingKeyInfo.indexes[keyIndex] = argIndex
routingKeyInfo.types[keyIndex] = boundColumn.TypeInfo
routingKeyInfo.names[keyIndex] = boundColumn.Name
break
}
}
if routingKeyInfo.indexes[keyIndex] == -1 {
// missing a routing key column mapping
// no routing key, and no error
return nil, nil
}
}
// cache this result
inflight.value = routingKeyInfo
return routingKeyInfo, nil
}
func (b *Batch) execute(ctx context.Context, conn *Conn) *Iter {
return conn.executeBatch(ctx, b)
}
func (s *Session) executeBatch(batch *Batch) *Iter {
// fail fast
if s.Closed() {
return &Iter{err: ErrSessionClosed}
}
// Prevent the execution of the batch if greater than the limit
// Currently batches have a limit of 65536 queries.
// https://datastax-oss.atlassian.net/browse/JAVA-229
if batch.Size() > BatchSizeMaximum {
return &Iter{err: ErrTooManyStmts}
}
iter, err := s.executor.executeQuery(batch)
if err != nil {
return &Iter{err: err}
}
return iter
}
// ExecuteBatch executes a batch operation and returns nil if successful
// otherwise an error is returned describing the failure.
func (s *Session) ExecuteBatch(batch *Batch) error {
iter := s.executeBatch(batch)
return iter.Close()
}
// ExecuteBatchCAS executes a batch operation and returns true if successful and
// an iterator (to scan additional rows if more than one conditional statement)
// was sent.
// Further scans on the interator must also remember to include
// the applied boolean as the first argument to *Iter.Scan
func (s *Session) ExecuteBatchCAS(batch *Batch, dest ...interface{}) (applied bool, iter *Iter, err error) {
iter = s.executeBatch(batch)
if err := iter.checkErrAndNotFound(); err != nil {
iter.Close()
return false, nil, err
}
if len(iter.Columns()) > 1 {
dest = append([]interface{}{&applied}, dest...)
iter.Scan(dest...)
} else {
iter.Scan(&applied)
}
return applied, iter, nil
}
// MapExecuteBatchCAS executes a batch operation much like ExecuteBatchCAS,
// however it accepts a map rather than a list of arguments for the initial
// scan.
func (s *Session) MapExecuteBatchCAS(batch *Batch, dest map[string]interface{}) (applied bool, iter *Iter, err error) {
iter = s.executeBatch(batch)
if err := iter.checkErrAndNotFound(); err != nil {
iter.Close()
return false, nil, err
}
iter.MapScan(dest)
applied = dest["[applied]"].(bool)
delete(dest, "[applied]")
// we usually close here, but instead of closing, just returin an error
// if MapScan failed. Although Close just returns err, using Close
// here might be confusing as we are not actually closing the iter
return applied, iter, iter.err
}
type hostMetrics struct {
// Attempts is count of how many times this query has been attempted for this host.
// An attempt is either a retry or fetching next page of results.
Attempts int
// TotalLatency is the sum of attempt latencies for this host in nanoseconds.
TotalLatency int64
}
type queryMetrics struct {
l sync.RWMutex
m map[string]*hostMetrics
// totalAttempts is total number of attempts.
// Equal to sum of all hostMetrics' Attempts.
totalAttempts int
}
// preFilledQueryMetrics initializes new queryMetrics based on per-host supplied data.
func preFilledQueryMetrics(m map[string]*hostMetrics) *queryMetrics {
qm := &queryMetrics{m: m}
for _, hm := range qm.m {
qm.totalAttempts += hm.Attempts
}
return qm
}
// hostMetrics returns a snapshot of metrics for given host.
// If the metrics for host don't exist, they are created.
func (qm *queryMetrics) hostMetrics(host *HostInfo) *hostMetrics {
qm.l.Lock()
metrics := qm.hostMetricsLocked(host)
copied := new(hostMetrics)
*copied = *metrics
qm.l.Unlock()
return copied
}
// hostMetricsLocked gets or creates host metrics for given host.
// It must be called only while holding qm.l lock.
func (qm *queryMetrics) hostMetricsLocked(host *HostInfo) *hostMetrics {
metrics, exists := qm.m[host.ConnectAddress().String()]
if !exists {
// if the host is not in the map, it means it's been accessed for the first time
metrics = &hostMetrics{}
qm.m[host.ConnectAddress().String()] = metrics
}
return metrics
}
// attempts returns the number of times the query was executed.
func (qm *queryMetrics) attempts() int {
qm.l.Lock()
attempts := qm.totalAttempts
qm.l.Unlock()
return attempts
}
func (qm *queryMetrics) latency() int64 {
qm.l.Lock()
var (
attempts int
latency int64
)
for _, metric := range qm.m {
attempts += metric.Attempts
latency += metric.TotalLatency
}
qm.l.Unlock()
if attempts > 0 {
return latency / int64(attempts)
}
return 0
}
// attempt adds given number of attempts and latency for given host.
// It returns previous total attempts.
// If needsHostMetrics is true, a copy of updated hostMetrics is returned.
func (qm *queryMetrics) attempt(addAttempts int, addLatency time.Duration,
host *HostInfo, needsHostMetrics bool) (int, *hostMetrics) {
qm.l.Lock()
totalAttempts := qm.totalAttempts
qm.totalAttempts += addAttempts
updateHostMetrics := qm.hostMetricsLocked(host)
updateHostMetrics.Attempts += addAttempts
updateHostMetrics.TotalLatency += addLatency.Nanoseconds()
var hostMetricsCopy *hostMetrics
if needsHostMetrics {
hostMetricsCopy = new(hostMetrics)
*hostMetricsCopy = *updateHostMetrics
}
qm.l.Unlock()
return totalAttempts, hostMetricsCopy
}
// Query represents a CQL statement that can be executed.
type Query struct {
stmt string
values []interface{}
cons Consistency
pageSize int
routingKey []byte
pageState []byte
prefetch float64
trace Tracer
observer QueryObserver
session *Session
conn *Conn
rt RetryPolicy
spec SpeculativeExecutionPolicy
binding func(q *QueryInfo) ([]interface{}, error)
serialCons Consistency
defaultTimestamp bool
defaultTimestampValue int64
disableSkipMetadata bool
context context.Context
idempotent bool
customPayload map[string][]byte
metrics *queryMetrics
refCount uint32
disableAutoPage bool
// getKeyspace is field so that it can be overriden in tests
getKeyspace func() string
// used by control conn queries to prevent triggering a write to systems
// tables in AWS MCS see
skipPrepare bool
// routingInfo is a pointer because Query can be copied and copyable struct can't hold a mutex.
routingInfo *queryRoutingInfo
}
type queryRoutingInfo struct {
// mu protects contents of queryRoutingInfo.
mu sync.RWMutex
// "lwt" denotes the query being an LWT operation
// In effect if the query is of the form "INSERT/UPDATE/DELETE ... IF ..."
// For more details see https://docs.scylladb.com/using-scylla/lwt/
lwt bool
// If not nil, represents a custom partitioner for the table.
partitioner partitioner
keyspace string
table string
}
func (qri *queryRoutingInfo) isLWT() bool {
qri.mu.RLock()
defer qri.mu.RUnlock()
return qri.lwt
}
func (qri *queryRoutingInfo) getPartitioner() partitioner {
qri.mu.RLock()
defer qri.mu.RUnlock()
return qri.partitioner
}
func (q *Query) defaultsFromSession() {
s := q.session
s.mu.RLock()
q.cons = s.cons
q.pageSize = s.pageSize
q.trace = s.trace
q.observer = s.queryObserver
q.prefetch = s.prefetch
q.rt = s.cfg.RetryPolicy