The maximum number of rows to scan to look for the columns available in a table.
The columns in a table must be determined by scanning table rows. This value determines the maximum number of rows that will be scanned.
Setting a high value may decrease performance. Setting a low value may prevent the data type from being determined properly, especially when there is null data.
Setting to a value of -1 causes the adapter to scan an arbitrary number of rows until it reaches the final row.