[receiver/postgresql] Fix for memory leak when using top queries (open-telemetry#43115)

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

Fix for memory leak when using `ObfuscateSQLStringWithOptions()` in the
obfuscate library

Similar fix done in [SQL Server
receiver](https://github.com/open-telemetry/opentelemetry-collector-contrib/pull/42303/files
) and [OracleDB
Receiver](open-telemetry#43096)

<!-- Issue number (e.g. open-telemetry#1234) or full URL to issue, if applicable. -->
#### Link to tracking issue
Fixes open-telemetry#43076

---------

Signed-off-by: Paulo Dias <[email protected]>
Co-authored-by: Christos Markou <[email protected]>

Author: 2 people

.chloggen/fix_43076.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: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: postgreqsqlreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Fix for memory leak when using top queries
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [43076]
+
+# (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:
+
+# 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: [user]

receiver/postgresqlreceiver/obfuscate.go

@@ -176,6 +176,12 @@ var defaultSQLPlanObfuscateSettings = obfuscate.JSONConfig{
 func lazyInitObfuscator() *obfuscate.Obfuscator {
 	obfuscatorLoader.Do(func() {
 		obfuscator = obfuscate.NewObfuscator(obfuscate.Config{
+			SQL: obfuscate.SQLConfig{
+				DBMS:         "postgresql",
+				KeepSQLAlias: true,
+				KeepBoolean:  true,
+				KeepNull:     true,
+			},
 			SQLExecPlan:          defaultSQLPlanObfuscateSettings,
 			SQLExecPlanNormalize: defaultSQLPlanNormalizeSettings,
 		})
@@ -185,12 +191,7 @@ func lazyInitObfuscator() *obfuscate.Obfuscator {
 
 // obfuscateSQL obfuscates & normalizes the provided SQL query, writing the error into errResult if the operation fails.
 func obfuscateSQL(rawQuery string) (string, error) {
-	obfuscatedQuery, err := lazyInitObfuscator().ObfuscateSQLStringWithOptions(rawQuery, &obfuscate.SQLConfig{
-		// the information is need to be kept to prepare statement for explain.
-		KeepSQLAlias: true,
-		KeepBoolean:  true,
-		KeepNull:     true,
-	}, "")
+	obfuscatedQuery, err := lazyInitObfuscator().ObfuscateSQLString(rawQuery)
 	if err != nil {
 		return "", err
 	}