more cleanups

[pstop.git] / p_s / setup_instruments / setup_instruments.go

diff --git a/p_s/setup_instruments/setup_instruments.go b/p_s/setup_instruments/setup_instruments.go
index 285c86e..cf4e347 100644 (file)
--- a/p_s/setup_instruments/setup_instruments.go
+++ b/p_s/setup_instruments/setup_instruments.go
@@ -1,3 +1,4 @@
+// manage the configuration of performance_schema.setup_instruments
 package setup_instruments
 
 import (
@@ -10,24 +11,31 @@ import (
 // We only match on the error number
 // Error 1142: UPDATE command denied to user
 // Error 1290: The MySQL server is running with the --read-only option so it cannot execute this statement
-var EXPECTED_UPDATE_ERRORS = []string { "Error 1142", "Error 1290" }
+var EXPECTED_UPDATE_ERRORS = []string{
+       "Error 1142",
+       "Error 1290",
+}
 
-type setup_instruments_row struct {
+// one row of performance_schema.setup_instruments
+type table_row struct {
        NAME    string
        ENABLED string
        TIMED   string
 }
 
+type table_rows []table_row
+
+// SetupInstruments "object"
 type SetupInstruments struct {
        update_succeeded bool
-       rows []setup_instruments_row
+       rows             table_rows
 }
 
 // Change settings to monitor stage/sql/%
 func (si *SetupInstruments) EnableStageMonitoring(dbh *sql.DB) {
        sql := "SELECT NAME, ENABLED, TIMED FROM setup_instruments WHERE NAME LIKE 'stage/sql/%' AND ( enabled <> 'YES' OR timed <> 'YES' )"
        collecting := "Collecting p_s.setup_instruments stage/sql configuration settings"
-       updating   := "Updating p_s.setup_instruments to allow stage/sql configuration"
+       updating := "Updating p_s.setup_instruments to allow stage/sql configuration"
 
        si.ConfigureSetupInstruments(dbh, sql, collecting, updating)
 }
@@ -36,7 +44,7 @@ func (si *SetupInstruments) EnableStageMonitoring(dbh *sql.DB) {
 func (si *SetupInstruments) EnableMutexMonitoring(dbh *sql.DB) {
        sql := "SELECT NAME, ENABLED, TIMED FROM setup_instruments WHERE NAME LIKE 'wait/synch/mutex/%' AND ( enabled <> 'YES' OR timed <> 'YES' )"
        collecting := "Collecting p_s.setup_instruments wait/synch/mutex configuration settings"
-       updating   := "Updating p_s.setup_instruments to allow wait/synch/mutex configuration"
+       updating := "Updating p_s.setup_instruments to allow wait/synch/mutex configuration"
 
        si.ConfigureSetupInstruments(dbh, sql, collecting, updating)
 }
@@ -45,7 +53,7 @@ func (si *SetupInstruments) EnableMutexMonitoring(dbh *sql.DB) {
 func (si *SetupInstruments) ConfigureSetupInstruments(dbh *sql.DB, sql string, collecting, updating string) {
        // setup the old values in case they're not set
        if si.rows == nil {
-               si.rows = make([]setup_instruments_row, 0, 500)
+               si.rows = make([]table_row, 0, 500)
        }
 
        lib.Logger.Println(collecting)
@@ -58,7 +66,7 @@ func (si *SetupInstruments) ConfigureSetupInstruments(dbh *sql.DB, sql string, c
 
        count := 0
        for rows.Next() {
-               var r setup_instruments_row
+               var r table_row
                if err := rows.Scan(
                        &r.NAME,
                        &r.ENABLED,
@@ -78,9 +86,13 @@ func (si *SetupInstruments) ConfigureSetupInstruments(dbh *sql.DB, sql string, c
        lib.Logger.Println(updating)
 
        count = 0
+       update_sql := "UPDATE setup_instruments SET enabled = ?, TIMED = ? WHERE NAME = ?"
+       stmt, err := dbh.Prepare( update_sql )
+       if err != nil {
+               log.Fatal(err)
+       }
        for i := range si.rows {
-               sql := "UPDATE setup_instruments SET enabled = 'YES', TIMED = 'YES' WHERE NAME = '" + si.rows[i].NAME + "'"
-               if _, err := dbh.Exec(sql); err == nil {
+               if _, err := stmt.Exec(update_sql, "YES", "YES", si.rows[i].NAME); err == nil {
                        si.update_succeeded = true
                } else {
                        found_expected := false
@@ -90,10 +102,10 @@ func (si *SetupInstruments) ConfigureSetupInstruments(dbh *sql.DB, sql string, c
                                        break
                                }
                        }
-                       if ! found_expected {
+                       if !found_expected {
                                log.Fatal(err)
                        }
-                       lib.Logger.Println( "Insufficient privileges to UPDATE setup_instruments: " + err.Error() )
+                       lib.Logger.Println("Insufficient privileges to UPDATE setup_instruments: " + err.Error())
                        break
                }
                count++
@@ -103,11 +115,10 @@ func (si *SetupInstruments) ConfigureSetupInstruments(dbh *sql.DB, sql string, c
        }
 }
 
-
-// restore any changed rows back to their original state
+// restore setup_instruments rows to their previous settings
 func (si *SetupInstruments) RestoreConfiguration(dbh *sql.DB) {
        // If the previous update didn't work then don't try to restore
-       if ! si.update_succeeded {
+       if !si.update_succeeded {
                lib.Logger.Println("Not restoring p_s.setup_instruments to its original settings as previous UPDATE had failed")
                return
        } else {
@@ -116,9 +127,13 @@ func (si *SetupInstruments) RestoreConfiguration(dbh *sql.DB) {
 
        // update the rows which need to be set - do multiple updates but I don't care
        count := 0
+       update_sql := "UPDATE setup_instruments SET enabled = ?, TIMED = ? WHERE NAME = ?"
+       stmt, err := dbh.Prepare( update_sql )
+       if err != nil {
+               log.Fatal(err)
+       }
        for i := range si.rows {
-               sql := "UPDATE setup_instruments SET enabled = '" + si.rows[i].ENABLED + "', TIMED = '" + si.rows[i].TIMED + "' WHERE NAME = '" + si.rows[i].NAME + "'"
-               if _, err := dbh.Exec(sql); err != nil {
+               if _, err := stmt.Exec(update_sql, si.rows[i].ENABLED, si.rows[i].TIMED, si.rows[i].NAME ); err != nil {
                        log.Fatal(err)
                }
                count++