Add command-line option for lock timeout.

cmd/pgmetrics/main.go

@@ -40,6 +40,7 @@ Usage:
 
 General options:
   -t, --timeout=SECS           individual query timeout in seconds (default: 5)
+      --lock-timeout=MILLIS    lock timeout in milliseconds (default: 50)
   -i, --input=FILE             don't connect to db, instead read and display
                                    this previously saved JSON file
   -V, --version                output version information, then exit
@@ -193,6 +194,7 @@ func (o *options) parse() (args []string) {
 	s.SetProgram("pgmetrics")
 	// general
 	s.UintVarLong(&o.CollectConfig.TimeoutSec, "timeout", 't', "")
+	s.UintVarLong(&o.CollectConfig.LockTimeoutMillisec, "lock-timeout", 0, "")
 	s.BoolVarLong(&o.CollectConfig.NoSizes, "no-sizes", 'S', "")
 	s.StringVarLong(&o.input, "input", 'i', "")
 	help := s.StringVarLong(&o.help, "help", '?', "").SetOptional()
@@ -249,6 +251,11 @@ func (o *options) parse() (args []string) {
 		printTry()
 		os.Exit(2)
 	}
+	if o.CollectConfig.LockTimeoutMillisec == 0 {
+		fmt.Fprintln(os.Stderr, "lock-timeout must be greater than 0")
+		printTry()
+		os.Exit(2)
+	}
 	if err := getRegexp(o.CollectConfig.Schema); err != nil {
 		fmt.Fprintf(os.Stderr, "bad POSIX regular expression for -c/--schema: %v\n", err)
 		printTry()

collector/collect.go

@@ -61,8 +61,9 @@ func isValidIdent(s string) bool {
 // specify which metrics to collect and how.
 type CollectConfig struct {
 	// general
-	TimeoutSec uint
-	NoSizes    bool
+	TimeoutSec          uint
+	LockTimeoutMillisec uint
+	NoSizes             bool
 
 	// collection
 	Schema          string
@@ -92,7 +93,8 @@ type CollectConfig struct {
 func DefaultCollectConfig() CollectConfig {
 	cc := CollectConfig{
 		// ------------------ general
-		TimeoutSec: 5,
+		TimeoutSec:          5,
+		LockTimeoutMillisec: 50,
 		//NoSizes: false,
 
 		// ------------------ collection
@@ -176,7 +178,7 @@ func Collect(o CollectConfig, dbnames []string) *pgmetrics.Model {
 
 	// set timeouts (but not for pgbouncer, it does not like them)
 	if !(len(dbnames) == 1 && dbnames[0] == "pgbouncer") {
-		connstr += makeKV("lock_timeout", "50") // 50 msec. Just fail fast on locks.
+		connstr += makeKV("lock_timeout", strconv.Itoa(int(o.LockTimeoutMillisec)))
 		connstr += makeKV("statement_timeout", strconv.Itoa(int(o.TimeoutSec)*1000))
 	}