X-Git-Url: http://git.iain.cx/?a=blobdiff_plain;f=main.go;h=927a15193d539c9a74b063adddcad3836e75aa24;hb=da7982a6dc5c0387d4aadc996cfe5dc53dafbd45;hp=708a77aa0a7e37211d435731dd87844c555d9e97;hpb=2e1a0892e2e2240a1f2ab31ff9cacfa9b9243a74;p=pstop.git

diff --git a/main.go b/main.go
index 708a77a..927a151 100644
--- a/main.go
+++ b/main.go
@@ -4,11 +4,13 @@ package main
 
 import (
 	"database/sql"
+	"errors"
 	"flag"
 	"fmt"
 	"log"
 	"os"
 	"os/signal"
+	"regexp"
 	"runtime/pprof"
 	"syscall"
 	"time"
@@ -20,6 +22,7 @@ import (
 	"github.com/sjmudd/pstop/lib"
 	"github.com/sjmudd/pstop/state"
 	"github.com/sjmudd/pstop/version"
+	"github.com/sjmudd/pstop/wait_info"
 )
 
 const (
@@ -27,14 +30,19 @@ const (
 	db         = "performance_schema"
 )
 
-var flag_version = flag.Bool("version", false, "Show the version of "+lib.MyName())
-var flag_debug = flag.Bool("debug", false, "Enabling debug logging")
-var flag_help = flag.Bool("help", false, "Provide some help for "+lib.MyName())
-var cpuprofile = flag.String("cpuprofile", "", "write cpu profile to file")
+var (
+	flag_version = flag.Bool("version", false, "Show the version of "+lib.MyName())
+	flag_debug   = flag.Bool("debug", false, "Enabling debug logging")
+	flag_help    = flag.Bool("help", false, "Provide some help for "+lib.MyName())
+	cpuprofile   = flag.String("cpuprofile", "", "write cpu profile to file")
+
+	re_valid_version = regexp.MustCompile(`^(5\.[67]\.|10\.[01])`)
+)
 
 func get_db_handle() *sql.DB {
 	var err error
 	var dbh *sql.DB
+	lib.Logger.Println("get_db_handle() connecting to database")
 
 	dbh, err = mysql_defaults_file.OpenUsingDefaultsFile(sql_driver, "", "performance_schema")
 	if err != nil {
@@ -72,6 +80,44 @@ func usage() {
 	fmt.Println("-version   show the version")
 }
 
+// pstop requires MySQL 5.6+ or MariaDB 10.0+. Check the version
+// rather than giving an error message if the requires P_S tables can't
+// be found.
+func validate_mysql_version(dbh *sql.DB) error {
+	var tables = [...]string{
+		"performance_schema.file_summary_by_instance",
+		"performance_schema.table_io_waits_summary_by_table",
+		"performance_schema.table_lock_waits_summary_by_table",
+	}
+
+	lib.Logger.Println("validate_mysql_version()")
+
+	lib.Logger.Println("- Getting MySQL version")
+	err, mysql_version := lib.SelectGlobalVariableByVariableName(dbh, "VERSION")
+	if err != nil {
+		return err
+	}
+	lib.Logger.Println("- mysql_version: '" + mysql_version + "'")
+
+	if !re_valid_version.MatchString(mysql_version) {
+		err := errors.New(lib.MyName() + " does not work with MySQL version " + mysql_version)
+		return err
+	}
+	lib.Logger.Println("OK: MySQL version is valid, continuing")
+
+	lib.Logger.Println("Checking access to required tables:")
+	for i := range tables {
+		if err := lib.CheckTableAccess(dbh, tables[i]); err == nil {
+			lib.Logger.Println("OK: " + tables[i] + " found")
+		} else {
+			return err
+		}
+	}
+	lib.Logger.Println("OK: all table checks passed")
+
+	return nil
+}
+
 func main() {
 	flag.Parse()
 
@@ -98,9 +144,16 @@ func main() {
 	}
 
 	lib.Logger.Println("Starting " + lib.MyName())
+
+	dbh := get_db_handle()
+	if err := validate_mysql_version(dbh); err != nil {
+		log.Fatal(err)
+	}
+
 	var state state.State
+	var wi wait_info.WaitInfo
+	wi.SetWaitInterval(time.Second)
 
-	interval := time.Second
 	sigChan := make(chan os.Signal, 1)
 	done := make(chan struct{})
 	defer close(done)
@@ -108,9 +161,7 @@ func main() {
 
 	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
 
-	ticker := time.NewTicker(interval) // generate a periodic signal
-
-	state.Setup(get_db_handle())
+	state.Setup(dbh)
 
 	finished := false
 	for !finished {
@@ -121,8 +172,9 @@ func main() {
 		case sig := <-sigChan:
 			fmt.Println("Caught a signal", sig)
 			done <- struct{}{}
-		case <-ticker.C:
+		case <-wi.WaitNextPeriod():
 			state.Collect()
+			wi.CollectedNow()
 			state.Display()
 		case event := <-termboxChan:
 			// switch on event type
@@ -137,15 +189,11 @@ func main() {
 				}
 				switch event.Ch {
 				case '-': // decrease the interval if > 1
-					if interval > time.Second {
-						ticker.Stop()
-						interval -= time.Second
-						ticker = time.NewTicker(interval)
+					if wi.WaitInterval() > time.Second {
+						wi.SetWaitInterval(wi.WaitInterval() - time.Second)
 					}
 				case '+': // increase interval by creating a new ticker
-					ticker.Stop()
-					interval += time.Second
-					ticker = time.NewTicker(interval)
+					wi.SetWaitInterval(wi.WaitInterval() + time.Second)
 				case 'h': // help
 					state.SetHelp(!state.Help())
 				case 'q': // quit
@@ -166,6 +214,5 @@ func main() {
 		}
 	}
 	state.Cleanup()
-	ticker.Stop()
 	lib.Logger.Println("Terminating " + lib.MyName())
 }