Get-DbaXESession - Close the cloned connection behind the XEStore

Every call cloned the SqlConnection for its XEStore and never closed
the clone: one sleeping session per call, held until the process exits.
Because the whole Extended Events family funnels through this command -
Start-DbaXESession even re-queries through it after every start - the
leak multiplied across Start, Stop, Remove, ConvertTo, Watch and the
Export commands. The first -CheckSleepingConnections full run flagged
Start-DbaXESession at +15, ConvertTo at +7 and Remove at +6.

The store connection is now disconnected after the sessions are
enumerated and emitted. The emitted objects keep their Store note
property working: SFC transparently reconnects from the pool when a
downstream command uses the store again, which the lab probe confirmed
for piped Start and Stop and a test now pins.

Measured on SQL03\SQL2019: three Get calls used to add three sessions
(regression test red on the unfixed command: expected 4, got 7), now
add none. Runner measurements of the family files: Start-DbaXESession
15 -> 7, Remove-DbaXESession 6 -> 2, ConvertTo-DbaXESession 7 -> 3.
The residue in Start comes from a different, smaller mechanism (the
reopened store of a piped object stays checked out once per pipeline)
and is left for a follow-up.

(do *XESession*)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: andreasjordan

public/Get-DbaXESession.ps1

@@ -142,6 +142,11 @@ function Get-DbaXESession {
                 Add-Member -Force -InputObject $x -MemberType NoteProperty -Name Store -Value $XEStore
                 Select-DefaultView -InputObject $x -Property ComputerName, InstanceName, SqlInstance, Name, Status, StartTime, AutoStart, State, Targets, TargetFile, Events, MaxMemory, MaxEventSize
             }
+
+            # The store rides a cloned connection that nothing ever closed, so every call parked one
+            # more session on the instance until the process ended. Close it here; when a consumer of
+            # the emitted objects uses the store again, SFC transparently reconnects from the pool.
+            $XEStore.SfcConnection.Disconnect()
         }
     }
 }

tests/Get-DbaXESession.Tests.ps1

@@ -33,4 +33,47 @@ Describe $CommandName -Tag IntegrationTests {
             $results.Name -eq "system_health" | Should -Be $true
         }
     }
+
+    Context "When querying sessions repeatedly" {
+        BeforeAll {
+            $PSDefaultParameterValues["*-Dba*:EnableException"] = $true
+
+            # The command used to leave the cloned connection of its XEStore open, one new sleeping
+            # session per call. Count sessions through a server object opened once, because a per-call
+            # counting command would open connections of its own.
+            $countServer = Connect-DbaInstance -SqlInstance $TestConfig.InstanceSingle -NonPooledConnection
+            $countQuery = @"
+select count(*)
+from sys.dm_exec_sessions
+where program_name like 'dbatools%'
+  and status = 'sleeping'
+  and session_id <> @@spid
+"@
+
+            # One warm-up call so the shared pooled connection exists before the baseline is taken.
+            $null = Get-DbaXESession -SqlInstance $TestConfig.InstanceSingle -Session system_health
+            $sleepingBefore = $countServer.ConnectionContext.ExecuteScalar($countQuery)
+
+            foreach ($i in 1..3) {
+                $null = Get-DbaXESession -SqlInstance $TestConfig.InstanceSingle -Session system_health
+            }
+            $sleepingAfter = $countServer.ConnectionContext.ExecuteScalar($countQuery)
+
+            $PSDefaultParameterValues.Remove("*-Dba*:EnableException")
+        }
+
+        AfterAll {
+            $countServer.ConnectionContext.Disconnect()
+        }
+
+        It "Leaves no sleeping session behind" {
+            $sleepingAfter | Should -Be $sleepingBefore
+        }
+
+        It "Emits objects whose store still works after the connection is returned" {
+            $result = Get-DbaXESession -SqlInstance $TestConfig.InstanceSingle -Session system_health
+            # The store must transparently reconnect for downstream commands like Start or Stop.
+            $result.Store.Sessions.Name | Should -Contain "system_health"
+        }
+    }
 }