[receiver/postgresql] Add more Table Metrics (#13229)

Adds the following metrics:
    postgresql.database.count
    postgresql.table.count
    postgresql.table.size
    postgresql.table.vacuum.count

receiver/postgresqlreceiver/client.go

@@ -209,14 +209,16 @@ func (c *postgreSQLClient) getDatabaseSize(ctx context.Context, databases []stri
 
 // tableStats contains a result for a row of the getDatabaseTableMetrics result
 type tableStats struct {
- database string
- table string
- live int64
- dead int64
- inserts int64
- upd int64
- del int64
- hotUpd int64
+ database string
+ table string
+ live int64
+ dead int64
+ inserts int64
+ upd int64
+ del int64
+ hotUpd int64
+ size int64
+ vacuumCount int64
 }
 
 func (c *postgreSQLClient) getDatabaseTableMetrics(ctx context.Context, db string) (map[tableIdentifier]tableStats, error) {
@@ -226,7 +228,9 @@ func (c *postgreSQLClient) getDatabaseTableMetrics(ctx context.Context, db strin
  n_tup_ins AS ins,
  n_tup_upd AS upd,
  n_tup_del AS del,
- n_tup_hot_upd AS hot_upd
+ n_tup_hot_upd AS hot_upd,
+ pg_relation_size(relid) AS table_size,
+ vacuum_count
  FROM pg_stat_user_tables;`
 
  ts := map[tableIdentifier]tableStats{}
@@ -237,20 +241,22 @@ func (c *postgreSQLClient) getDatabaseTableMetrics(ctx context.Context, db strin
  }
  for rows.Next() {
  var table string
- var live, dead, ins, upd, del, hotUpd int64
- err = rows.Scan(&table, &live, &dead, &ins, &upd, &del, &hotUpd)
+ var live, dead, ins, upd, del, hotUpd, tableSize, vacuumCount int64
+ err = rows.Scan(&table, &live, &dead, &ins, &upd, &del, &hotUpd, &tableSize, &vacuumCount)
  if err != nil {
  errors = multierr.Append(errors, err)
  continue
  }
  ts[tableKey(db, table)] = tableStats{
- database: db,
- table: table,
- live: live,
- inserts: ins,
- upd: upd,
- del: del,
- hotUpd: hotUpd,
+ database: db,
+ table: table,
+ live: live,
+ inserts: ins,
+ upd: upd,
+ del: del,
+ hotUpd: hotUpd,
+ size: tableSize,
+ vacuumCount: vacuumCount,
  }
  }
  return ts, errors

receiver/postgresqlreceiver/documentation.md

@@ -11,12 +11,16 @@ These are the metrics available for this scraper.
 | **postgresql.backends** | The number of backends. | 1 | Sum(Int) | <ul> <li>database</li> </ul> |
 | **postgresql.blocks_read** | The number of blocks read. | 1 | Sum(Int) | <ul> <li>database</li> <li>table</li> <li>source</li> </ul> |
 | **postgresql.commits** | The number of commits. | 1 | Sum(Int) | <ul> <li>database</li> </ul> |
+| **postgresql.database.count** | Number of user databases. | {databases} | Sum(Int) | <ul> </ul> |
 | **postgresql.db_size** | The database disk usage. | By | Sum(Int) | <ul> <li>database</li> </ul> |
 | **postgresql.index.scans** | The number of index scans on a table. | {scans} | Sum(Int) | <ul> </ul> |
 | **postgresql.index.size** | The size of the index on disk. | By | Gauge(Int) | <ul> </ul> |
 | **postgresql.operations** | The number of db row operations. | 1 | Sum(Int) | <ul> <li>database</li> <li>table</li> <li>operation</li> </ul> |
 | **postgresql.rollbacks** | The number of rollbacks. | 1 | Sum(Int) | <ul> <li>database</li> </ul> |
 | **postgresql.rows** | The number of rows in the database. | 1 | Sum(Int) | <ul> <li>database</li> <li>table</li> <li>state</li> </ul> |
+| **postgresql.table.count** | Number of user tables in a database. | | Sum(Int) | <ul> </ul> |
+| **postgresql.table.size** | Disk space used by a table. | By | Sum(Int) | <ul> </ul> |
+| **postgresql.table.vacuum.count** | Number of times a table has manually been vacuumed. | {vacuums} | Sum(Int) | <ul> </ul> |
 
 **Highlighted metrics** are emitted by default. Other metrics are optional and not emitted by default.
 Any metric can be enabled or disabled with the following scraper configuration: