Optimizing Memory Usage while Working with Big Files having Large Datasets with Node.js via C++

When building a workbook with large data sets, or reading a big Microsoft Excel file, the total amount of RAM the process will take is always a concern. There are measures that can be adapted to cope with the challenge. Aspose.Cells for Node.js via C++ provides some relevant options and API calls to lower, reduce and optimize memory use. Also, it can help the process work more efficiently and run faster.

Use the MemorySetting.MemoryPreference option to optimize memory use for cells data and decrease the overall memory cost. When building a large data set for cells, it can save a certain amount of memory compared to using the default setting (MemorySetting.Normal).

Optimizing Memory

Reading Large Excel Files

The following example shows how to read a large Microsoft Excel file in optimized mode.

const path = require("path");
const AsposeCells = require("aspose.cells.node");

// The path to the documents directory.
const dataDir = path.join(__dirname, "data");
// Specify the LoadOptions
const opt = new AsposeCells.LoadOptions();
// Set the memory preferences
opt.setMemorySetting(AsposeCells.MemorySetting.MemoryPreference);

// Instantiate the Workbook
// Load the Big Excel file having large Data set in it
const wb = new AsposeCells.Workbook(path.join(dataDir, "Book1.xlsx"), opt);

Writing Large Excel Files

The following example shows how to write a large dataset to a worksheet in an optimized mode.

const AsposeCells = require("aspose.cells.node");
const path = require("path");

// The path to the documents directory.
const dataDir = path.join(__dirname, "data");
const filePath = path.join(dataDir, "sample.xlsx");
// Loads the workbook which contains hidden external links
const wb = new AsposeCells.Workbook();

// Set the memory preferences
wb.getSettings().setMemorySetting(AsposeCells.MemorySetting.MemoryPreference);

// Note: The memory settings also would not work for the default sheet i.e., "Sheet1" etc. automatically created by the Workbook

// To change the memory setting of existing sheets, please change memory setting for them manually:
let cells = wb.getWorksheets().get(0).getCells();
cells.setMemorySetting(AsposeCells.MemorySetting.MemoryPreference);

// Input large dataset into the cells of the worksheet.
// Your code goes here.
// .........

// Get cells of the newly created Worksheet "Sheet2" whose memory setting is same with the one defined in WorkbookSettings:
cells = wb.getWorksheets().add("Sheet2").getCells();
// .........
// Input large dataset into the cells of the worksheet.
// Your code goes here.
// .........

Caution

The default option, MemorySetting.Normal is applied for all versions. For some situations, such as building a workbook with a large data set for cells, the MemorySetting.MemoryPreference option may optimize the memory use and decrease the memory cost for the application. However, this option may degrade performance in some special cases such as follow.

1. Accessing Cells Randomly and Repeatedly: The most efficient sequence for accessing the cells collection is cell by cell in one row, and then row by row. Especially, if you access rows/cells by the Enumerator acquired from Cells, RowCollection, and Row, the performance would be maximized with MemorySetting.MemoryPreference.
2. Inserting & Deleting Cells & Rows: Please note that if there are lots of insert/delete operations for Cells/Rows, the performance degradation will be notable for MemoryPreference mode as compared to the Normal mode.
3. Operating on Different Cell Types: If most of the cells contain string values or formulas, the memory cost will be the same as Normal mode but if there are lots of empty cells, or cell values are numeric, bool and so on, the MemorySetting.MemoryPreference option will give better performance.