Copy-DbaDbTableData - Fix data ordering issue when copying tables without explicit ORDER BY (#9927)

Co-authored-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>

Author: potatoqualitee

public/Copy-DbaDbTableData.ps1

@@ -412,7 +412,58 @@ function Copy-DbaDbTableData {
 
 
                 if (Test-Bound -ParameterName Query -Not) {
-                    $Query = "SELECT * FROM $fqtnfrom"
+                    # Build ORDER BY clause to ensure consistent row order
+                    # This prevents data misalignment when copying tables without explicit ordering
+                    $orderByClause = ""
+
+                    # Refresh indexes to ensure we have current metadata
+                    $sqlObject.Indexes.Refresh()
+
+                    # Option 1: Use clustered index columns for ordering (most common and performant)
+                    $clusteredIndex = $sqlObject.Indexes | Where-Object IsClustered -eq $true | Select-Object -First 1
+                    if ($clusteredIndex) {
+                        $orderColumns = $clusteredIndex.IndexedColumns | Sort-Object IndexKeyPosition | ForEach-Object {
+                            $colName = $_.Name
+                            $descending = if ($_.Descending) { " DESC" } else { "" }
+                            "[$colName]$descending"
+                        }
+                        if ($orderColumns) {
+                            $orderByClause = " ORDER BY " + ($orderColumns -join ", ")
+                            Write-Message -Level Verbose -Message "Using clustered index for ordering: $orderByClause"
+                        }
+                    }
+
+                    # Option 2: If no clustered index, try primary key
+                    if (-not $orderByClause) {
+                        $primaryKey = $sqlObject.Indexes | Where-Object IndexKeyType -eq "DriPrimaryKey" | Select-Object -First 1
+                        if ($primaryKey) {
+                            $orderColumns = $primaryKey.IndexedColumns | Sort-Object IndexKeyPosition | ForEach-Object {
+                                $colName = $_.Name
+                                $descending = if ($_.Descending) { " DESC" } else { "" }
+                                "[$colName]$descending"
+                            }
+                            if ($orderColumns) {
+                                $orderByClause = " ORDER BY " + ($orderColumns -join ", ")
+                                Write-Message -Level Verbose -Message "Using primary key for ordering: $orderByClause"
+                            }
+                        }
+                    }
+
+                    # Option 3: If using KeepIdentity and an identity column exists, order by it
+                    if (-not $orderByClause -and $KeepIdentity) {
+                        $identityColumn = $sqlObject.Columns | Where-Object Identity -eq $true | Select-Object -First 1
+                        if ($identityColumn) {
+                            $orderByClause = " ORDER BY [$($identityColumn.Name)]"
+                            Write-Message -Level Verbose -Message "Using identity column for ordering: $orderByClause"
+                        }
+                    }
+
+                    # If no ordering found, log a warning for tables without proper keys
+                    if (-not $orderByClause) {
+                        Write-Message -Level Verbose -Message "No clustered index, primary key, or identity column found for ordering. Row order is not guaranteed."
+                    }
+
+                    $Query = "SELECT * FROM $fqtnfrom$orderByClause"
                     $sourceLabel = $fqtnfrom
                 } else {
                     $sourceLabel = "Query"

tests/Copy-DbaDbTableData.Tests.ps1

@@ -197,4 +197,45 @@ Describe $CommandName -Tag IntegrationTests {
             $destCount.Count | Should -Be 2
         }
     }
+
+    Context "Regression tests" {
+        BeforeAll {
+            $PSDefaultParameterValues["*-Dba*:EnableException"] = $true
+
+            $null = $sourceDb.Query("CREATE TABLE dbo.dbatoolsci_ordering_test (id INT IDENTITY(1,1) PRIMARY KEY, data_hash VARBINARY(32))")
+            $null = $sourceDb.Query("INSERT INTO dbo.dbatoolsci_ordering_test (data_hash) VALUES (0x0102030405), (0x0607080910), (0x1112131415)")
+
+            $PSDefaultParameterValues.Remove("*-Dba*:EnableException")
+        }
+
+        AfterAll {
+            $PSDefaultParameterValues["*-Dba*:EnableException"] = $true
+
+            $null = $sourceDb.Query("DROP TABLE IF EXISTS dbo.dbatoolsci_ordering_test")
+            $null = $destinationDb.Query("DROP TABLE IF EXISTS dbo.dbatoolsci_ordering_test_dest")
+
+            $PSDefaultParameterValues.Remove("*-Dba*:EnableException")
+        }
+
+        It "Should maintain correct row order when copying tables with varbinary fields (issue #9610)" {
+            $splatCopy = @{
+                SqlInstance      = $TestConfig.instance1
+                Destination      = $TestConfig.instance2
+                Database         = "tempdb"
+                Table            = "dbatoolsci_ordering_test"
+                DestinationTable = "dbatoolsci_ordering_test_dest"
+                AutoCreateTable  = $true
+            }
+            $result = Copy-DbaDbTableData @splatCopy
+            $result.RowsCopied | Should -Be 3
+
+            $sourceData = $sourceDb.Query("SELECT id, data_hash FROM dbo.dbatoolsci_ordering_test ORDER BY id")
+            $destData = $destinationDb.Query("SELECT id, data_hash FROM dbo.dbatoolsci_ordering_test_dest ORDER BY id")
+
+            for ($i = 0; $i -lt $sourceData.Count; $i++) {
+                $sourceData[$i].id | Should -Be $destData[$i].id
+                $sourceData[$i].data_hash | Should -Be $destData[$i].data_hash
+            }
+        }
+    }
 }