I have found a solution. Using a loop to paste row data into an array is actually pretty fast. The whole macro takes about 5mn to run, compared to more than 30mn for the original code.
The trick here was to break the 300,000 rows into smaller blocks of 25,000 rows to avoid the "out of memory" error.
Here is the code, maybe it will help somebody.
Sub DataRetrieval()
'This macro retrieves the Database data of defaulted companies.
Application.ScreenUpdating = False
Application.Calculation = xlCalculationManual
'VARIABLE DECLARATION
'Worksheets
Dim wsSource As Worksheet
Set wsSource = Sheets("Data Retrieval - Source")
Dim wsDestination As Worksheet
Set wsDestination = Sheets("Data Retrieval - Destination")
Dim wsDefaultList As Worksheet
Set wsDefaultList = Sheets("Default List")
'Core ID
Dim CoreIDSource As Long 'Core ID number of the sheet Data Retrieval - Source
Dim CoreIDModel As Long 'Core ID number of the sheet Model
Dim ComparingCoreID As Variant
'Count
Dim RowCountSource As Long 'Count the rows of the sheet Data Retrieval - Source
Dim RowCountDestination As Long 'Count the rows of the sheet Data Retrieval (destination)
RowCountDestination = 0
Dim ColumnCountDestination As Byte
'Tables
Dim TableSource() 'Dynamic table that will store data retrieved from Database
Erase TableSource 'Empty memory to avoid execution issues in case the program breaks before completion
'(tables also erased at the end)
Dim TableDestination(50000, 49) 'Table that will store the data from TableSource. Can store up to 50 columns
Erase TableDestination
Dim TableCoreID() 'Table that will store the list of revised CoreID
TableCoreID = wsDefaultList.Range("B5:B2000") 'First number is 1, not zero. The table is defined like that to avoid
'issues if one of the Core ID is blank (in that case, a table defined dynamically would stop at the blank cell)
'FORMATTING DESTINATION SHEET
'Preparing sheet Data Retrieval (destination)
wsDestination.Range("A3:CC500000").ClearContents
'Copy header
wsSource.Rows(3).Copy
wsDestination.Rows(3).PasteSpecial xlPasteValues
'Format header
With wsDestination.Rows(3)
.NumberFormat = "@"
.VerticalAlignment = xlCenter
.HorizontalAlignment = xlRight
With .Font
.Name = "Arial"
.FontStyle = "Bold"
.Size = 8
.Underline = xlUnderlineStyleNone
.ThemeColor = xlThemeColorDark1
End With
With .Interior
.ThemeColor = xlThemeColorAccent1
.Pattern = xlSolid
.PatternColorIndex = xlAutomatic
End With
End With
'STORING DATA IN TABLEDESTINATION VARIABLE
'25,000 rows
TableSource = wsSource.Range("A4:AX25003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'50,000 rows
TableSource = wsSource.Range("A25004:AX50003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'75,000 rows
TableSource = wsSource.Range("A50004:AX75003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'100,000 rows
TableSource = wsSource.Range("A75004:AX100003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'125,000 rows
TableSource = wsSource.Range("A100004:AX125003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'150,000 rows
TableSource = wsSource.Range("A125004:AX150003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'175,000 rows
TableSource = wsSource.Range("A150004:AX175003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'200,000 rows
TableSource = wsSource.Range("A175004:AX200003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'225,000 rows
TableSource = wsSource.Range("A200004:AX225003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'250,000 rows
TableSource = wsSource.Range("A225004:AX250003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'275,000 rows
TableSource = wsSource.Range("A250004:AX275003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'300,000 rows
TableSource = wsSource.Range("A275004:AX300003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'325,000 rows
TableSource = wsSource.Range("A300004:AX325003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'350,000 rows
TableSource = wsSource.Range("A325004:AX350003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'375,000 rows
TableSource = wsSource.Range("A350004:AX375003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'400,000 rows
TableSource = wsSource.Range("A375004:AX400003") 'First row and column numbers are 1 and not 0
Call LoopRetrieveDefaultData(RowCountSource, TableSource, TableCoreID, ColumnCountDestination, TableDestination, RowCountDestination)
'PASTING DATA IN SHEET DESTINATION AND FORMATTING
'Paste TableSource
wsDestination.Range("A4:AX50004") = TableDestination
'Format pasted area
wsDestination.Select 'The sheet must be activated
wsDestination.Range("A4:AX50004").Select
Call TableRows
wsDestination.Cells.HorizontalAlignment = xlLeft
'Empty memory
Erase TableSource
Erase TableDestination
Erase TableCoreID
Application.ScreenUpdating = True
Application.Calculation = xlCalculationAutomatic
End Sub
Sub LoopRetrieveDefaultData(RowCountSource As Long, TableSource As Variant, TableCoreID As Variant, ColumnCountDestination As Byte, TableDestination As Variant, RowCountDestination As Long)
For RowCountSource = 1 To 25000
If IsError(Application.Match(TableSource(RowCountSource, 2), TableCoreID, 0)) = False Then 'Comparing Core ID. The
'column number is 2 and not 1 because the first column of the table is 1
'from TableSource (Arrow Bar data) to list of defaults Core ID(TableCoreID)
For ColumnCountDestination = 0 To 49 'Paste correponding row in TableDestination
TableDestination(RowCountDestination, ColumnCountDestination) = TableSource(RowCountSource, ColumnCountDestination + 1)
Next ColumnCountDestination
RowCountDestination = RowCountDestination + 1
End If
Next RowCountSource
End Sub
wsdestination.Rows(3).value = wsSource.rows(3).value?