p_s/events_waits_summary_global_by_event_name/events_waits_summary_global_by_event_name_row.go

   1 // This file contains the library routines for managing the
   2 // table_io_waits_by_table table.
   3 package events_waits_summary_global_by_event_name
   4
   5 import (
   6         "database/sql"
   7         "fmt"
   8         "log"
   9         "sort"
  10         "strings"
  11
  12         "github.com/sjmudd/pstop/lib"
  13 )
  14
  15 // a row from performance_schema.events_waits_summary_global_by_event_name
  16 // Note: upper case names to match the performance_schema column names.
  17 // This type is _not_ meant to be exported.
  18 type events_waits_summary_global_by_event_name_row struct {
  19         EVENT_NAME     string
  20         SUM_TIMER_WAIT uint64
  21         COUNT_STAR     uint64
  22 }
  23 type events_waits_summary_global_by_event_name_rows []events_waits_summary_global_by_event_name_row
  24
  25 // trim off the leading 'wait/synch/mutex/innodb/'
  26 func (r *events_waits_summary_global_by_event_name_row) name() string {
  27         var n string
  28         if r.EVENT_NAME == "Totals" {
  29                 n += r.EVENT_NAME
  30         } else if len(r.EVENT_NAME) >= 24 {
  31                 n += r.EVENT_NAME[24:]
  32         }
  33         return n
  34 }
  35
  36 func (r *events_waits_summary_global_by_event_name_row) pretty_name() string {
  37         s := r.name()
  38         if len(s) > 30 {
  39                 s = s[:29]
  40         }
  41         return s
  42 }
  43
  44 func (r *events_waits_summary_global_by_event_name_row) headings() string {
  45         return fmt.Sprintf("%-30s %10s %6s", "Mutex Name", "Latency", "%")
  46 }
  47
  48 // generate a printable result
  49 func (r *events_waits_summary_global_by_event_name_row) row_content(totals events_waits_summary_global_by_event_name_row) string {
  50         name := r.pretty_name()
  51         if r.COUNT_STAR == 0 && name != "Totals" {
  52                 name = ""
  53         }
  54
  55         return fmt.Sprintf("%-30s %10s %6s",
  56                 name,
  57                 lib.FormatTime(r.SUM_TIMER_WAIT),
  58                 lib.FormatPct(lib.MyDivide(r.SUM_TIMER_WAIT, totals.SUM_TIMER_WAIT)))
  59 }
  60
  61 func (this *events_waits_summary_global_by_event_name_row) add(other events_waits_summary_global_by_event_name_row) {
  62         this.SUM_TIMER_WAIT += other.SUM_TIMER_WAIT
  63         this.COUNT_STAR += other.COUNT_STAR
  64 }
  65
  66 // subtract the countable values in one row from another
  67 func (this *events_waits_summary_global_by_event_name_row) subtract(other events_waits_summary_global_by_event_name_row) {
  68         // check for issues here (we have a bug) and log it
  69         // - this situation should not happen so there's a logic bug somewhere else
  70         if this.SUM_TIMER_WAIT >= other.SUM_TIMER_WAIT {
  71                 this.SUM_TIMER_WAIT -= other.SUM_TIMER_WAIT
  72                 this.COUNT_STAR -= other.COUNT_STAR
  73         } else {
  74                 lib.Logger.Println("WARNING: events_waits_summary_global_by_event_name_row.subtract() - subtraction problem! (not subtracting)")
  75                 lib.Logger.Println("this=", this)
  76                 lib.Logger.Println("other=", other)
  77         }
  78 }
  79
  80 func (t events_waits_summary_global_by_event_name_rows) totals() events_waits_summary_global_by_event_name_row {
  81         var totals events_waits_summary_global_by_event_name_row
  82         totals.EVENT_NAME = "Totals"
  83
  84         for i := range t {
  85                 totals.add(t[i])
  86         }
  87
  88         return totals
  89 }
  90
  91 func select_tiwsbt_rows(dbh *sql.DB) events_waits_summary_global_by_event_name_rows {
  92         var t events_waits_summary_global_by_event_name_rows
  93
  94         // we collect all information even if it's mainly empty as we may reference it later
  95         sql := "SELECT EVENT_NAME, SUM_TIMER_WAIT, COUNT_STAR FROM events_waits_summary_global_by_event_name WHERE SUM_TIMER_WAIT > 0 AND EVENT_NAME LIKE 'wait/synch/mutex/innodb/%'"
  96
  97         rows, err := dbh.Query(sql)
  98         if err != nil {
  99                 log.Fatal(err)
 100         }
 101         defer rows.Close()
 102
 103         for rows.Next() {
 104                 var r events_waits_summary_global_by_event_name_row
 105                 if err := rows.Scan(
 106                         &r.EVENT_NAME,
 107                         &r.SUM_TIMER_WAIT,
 108                         &r.COUNT_STAR); err != nil {
 109                         log.Fatal(err)
 110                 }
 111                 // we collect all information even if it's mainly empty as we may reference it later
 112                 t = append(t, r)
 113         }
 114         if err := rows.Err(); err != nil {
 115                 log.Fatal(err)
 116         }
 117
 118         return t
 119 }
 120
 121 func (t events_waits_summary_global_by_event_name_rows) Len() int      { return len(t) }
 122 func (t events_waits_summary_global_by_event_name_rows) Swap(i, j int) { t[i], t[j] = t[j], t[i] }
 123
 124 // sort by value (descending) but also by "name" (ascending) if the values are the same
 125 func (t events_waits_summary_global_by_event_name_rows) Less(i, j int) bool {
 126         return t[i].SUM_TIMER_WAIT > t[j].SUM_TIMER_WAIT
 127 }
 128
 129 func (t events_waits_summary_global_by_event_name_rows) Sort() {
 130         sort.Sort(t)
 131 }
 132
 133 // remove the initial values from those rows where there's a match
 134 // - if we find a row we can't match ignore it
 135 func (this *events_waits_summary_global_by_event_name_rows) subtract(initial events_waits_summary_global_by_event_name_rows) {
 136         initial_by_name := make(map[string]int)
 137
 138         // iterate over rows by name
 139         for i := range initial {
 140                 initial_by_name[initial[i].name()] = i
 141         }
 142
 143         for i := range *this {
 144                 this_name := (*this)[i].name()
 145                 if _, ok := initial_by_name[this_name]; ok {
 146                         initial_index := initial_by_name[this_name]
 147                         (*this)[i].subtract(initial[initial_index])
 148                 }
 149         }
 150 }
 151
 152 // if the data in t2 is "newer", "has more values" than t then it needs refreshing.
 153 // check this by comparing totals.
 154 func (t events_waits_summary_global_by_event_name_rows) needs_refresh(t2 events_waits_summary_global_by_event_name_rows) bool {
 155         my_totals := t.totals()
 156         t2_totals := t2.totals()
 157
 158         return my_totals.SUM_TIMER_WAIT > t2_totals.SUM_TIMER_WAIT
 159 }
 160
 161 // describe a whole row
 162 func (r events_waits_summary_global_by_event_name_row) String() string {
 163         return fmt.Sprintf("%-30s|%10s %10s %10s %10s %10s|%10s %10s|%10s %10s %10s %10s %10s|%10s %10s",
 164                 r.pretty_name(),
 165                 lib.FormatTime(r.SUM_TIMER_WAIT),
 166                 lib.FormatAmount(r.COUNT_STAR))
 167 }
 168
 169 // describe a whole table
 170 func (t events_waits_summary_global_by_event_name_rows) String() string {
 171         s := make([]string, len(t))
 172
 173         for i := range t {
 174                 s = append(s, t[i].String())
 175         }
 176
 177         return strings.Join(s, "\n")
 178 }