Add postgresql.temp.io metric (#41365)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description

Add `postgresql.temp.io` metric.

---------

Co-authored-by: Nico Stewart <[email protected]>

Author: nenadnoveljic

.chloggen/pg-temp-bytes.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: postgresqlreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add 'postgresql.temp.io' metric
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [41365]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: The metric emits the amount of data written to temporary files.
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

receiver/postgresqlreceiver/client.go

@@ -190,6 +190,7 @@ type databaseStats struct {
 	transactionCommitted int64
 	transactionRollback  int64
 	deadlocks            int64
+	tempIo               int64
 	tempFiles            int64
 	tupUpdated           int64
 	tupReturned          int64
@@ -202,7 +203,7 @@ type databaseStats struct {
 
 func (c *postgreSQLClient) getDatabaseStats(ctx context.Context, databases []string) (map[databaseName]databaseStats, error) {
 	query := filterQueryByDatabases(
-		"SELECT datname, xact_commit, xact_rollback, deadlocks, temp_files, tup_updated, tup_returned, tup_fetched, tup_inserted, tup_deleted, blks_hit, blks_read FROM pg_stat_database",
+		"SELECT datname, xact_commit, xact_rollback, deadlocks, temp_files, temp_bytes, tup_updated, tup_returned, tup_fetched, tup_inserted, tup_deleted, blks_hit, blks_read FROM pg_stat_database",
 		databases,
 		false,
 	)
@@ -217,8 +218,8 @@ func (c *postgreSQLClient) getDatabaseStats(ctx context.Context, databases []str
 
 	for rows.Next() {
 		var datname string
-		var transactionCommitted, transactionRollback, deadlocks, tempFiles, tupUpdated, tupReturned, tupFetched, tupInserted, tupDeleted, blksHit, blksRead int64
-		err = rows.Scan(&datname, &transactionCommitted, &transactionRollback, &deadlocks, &tempFiles, &tupUpdated, &tupReturned, &tupFetched, &tupInserted, &tupDeleted, &blksHit, &blksRead)
+		var transactionCommitted, transactionRollback, deadlocks, tempIo, tempFiles, tupUpdated, tupReturned, tupFetched, tupInserted, tupDeleted, blksHit, blksRead int64
+		err = rows.Scan(&datname, &transactionCommitted, &transactionRollback, &deadlocks, &tempFiles, &tempIo, &tupUpdated, &tupReturned, &tupFetched, &tupInserted, &tupDeleted, &blksHit, &blksRead)
 		if err != nil {
 			errs = multierr.Append(errs, err)
 			continue
@@ -228,6 +229,7 @@ func (c *postgreSQLClient) getDatabaseStats(ctx context.Context, databases []str
 				transactionCommitted: transactionCommitted,
 				transactionRollback:  transactionRollback,
 				deadlocks:            deadlocks,
+				tempIo:               tempIo,
 				tempFiles:            tempFiles,
 				tupUpdated:           tupUpdated,
 				tupReturned:          tupReturned,

receiver/postgresqlreceiver/documentation.md

@@ -315,6 +315,14 @@ The number of sequential scans.
 | ---- | ----------- | ---------- | ----------------------- | --------- |
 | {sequential_scan} | Sum | Int | Cumulative | true |
 
+### postgresql.temp.io
+
+Total amount of data written to temporary files by queries.
+
+| Unit | Metric Type | Value Type | Aggregation Temporality | Monotonic |
+| ---- | ----------- | ---------- | ----------------------- | --------- |
+| By | Sum | Int | Cumulative | true |
+
 ### postgresql.temp_files
 
 The number of temp files.

receiver/postgresqlreceiver/integration_test.go

@@ -96,6 +96,7 @@ func integrationTest(name string, databases []string, pgVersion string) func(*te
 				rCfg.Insecure = true
 				rCfg.Metrics.PostgresqlWalDelay.Enabled = true
 				rCfg.Metrics.PostgresqlDeadlocks.Enabled = true
+				rCfg.Metrics.PostgresqlTempIo.Enabled = true
 				rCfg.Metrics.PostgresqlTempFiles.Enabled = true
 				rCfg.Metrics.PostgresqlTupUpdated.Enabled = true
 				rCfg.Metrics.PostgresqlTupReturned.Enabled = true
@@ -110,7 +111,41 @@ func integrationTest(name string, databases []string, pgVersion string) func(*te
 		scraperinttest.WithExpectedFile(expectedFile),
 		scraperinttest.WithCompareOptions(
 			pmetrictest.IgnoreResourceMetricsOrder(),
-			pmetrictest.IgnoreMetricValues(),
+			pmetrictest.IgnoreMetricValues(
+				"postgresql.backends",
+				"postgresql.bgwriter.buffers.allocated",
+				"postgresql.bgwriter.buffers.writes",
+				"postgresql.bgwriter.checkpoint.count",
+				"postgresql.bgwriter.duration",
+				"postgresql.bgwriter.maxwritten",
+				"postgresql.blks_hit",
+				"postgresql.blks_read",
+				"postgresql.blocks_read",
+				"postgresql.commits",
+				"postgresql.connection.max",
+				"postgresql.database.count",
+				"postgresql.database.locks",
+				"postgresql.db_size",
+				"postgresql.deadlocks",
+				"postgresql.index.scans",
+				"postgresql.index.size",
+				"postgresql.operations",
+				"postgresql.replication.data_delay",
+				"postgresql.rollbacks",
+				"postgresql.rows",
+				"postgresql.sequential_scans",
+				"postgresql.table.count",
+				"postgresql.table.size",
+				"postgresql.table.vacuum.count",
+				"postgresql.tup_deleted",
+				"postgresql.tup_fetched",
+				"postgresql.tup_inserted",
+				"postgresql.tup_returned",
+				"postgresql.tup_updated",
+				"postgresql.wal.age",
+				"postgresql.wal.delay",
+				"postgresql.wal.lag",
+			),
 			pmetrictest.IgnoreSubsequentDataPoints("postgresql.backends"),
 			pmetrictest.IgnoreMetricDataPointsOrder(),
 			pmetrictest.IgnoreStartTimestamp(),

receiver/postgresqlreceiver/internal/metadata/generated_config.go

@@ -53,6 +53,8 @@ all_set:
       enabled: true
     postgresql.table.vacuum.count:
       enabled: true
+    postgresql.temp.io:
+      enabled: true
     postgresql.temp_files:
       enabled: true
     postgresql.tup_deleted:
@@ -139,6 +141,8 @@ none_set:
       enabled: false
     postgresql.table.vacuum.count:
       enabled: false
+    postgresql.temp.io:
+      enabled: false
     postgresql.temp_files:
       enabled: false
     postgresql.tup_deleted:

receiver/postgresqlreceiver/internal/metadata/generated_config_test.go

@@ -411,6 +411,14 @@ metrics:
       value_type: int
       monotonic: true
       aggregation_temporality: cumulative
+  postgresql.temp.io:
+    enabled: false
+    description: Total amount of data written to temporary files by queries.
+    unit: By
+    sum:
+      value_type: int
+      monotonic: true
+      aggregation_temporality: cumulative
   postgresql.wal.age:
     description: Age of the oldest WAL file.
     extended_documentation: |