Configuring server-side pagination

If your dataset contains thousands of records, you may struggle with load time and app performance. To improve performance, you can configure server-side pagination allowing you to load only the records on the current page.

Here, we talk about the Table component. But the guide is also suitable for Grid View and List view components.

It's important to keep in mind that when server-side pagination is enabled, table inline filters and sorting don't work automatically and need to be implemented separately.

In this article, we'll explore two types of server-side pagination:

• Page-based

• Cursor-based

Page-based pagination

To implement page-based server-side pagination, follow the steps below:

1. For the Table component, select the Server side pagination checkbox in the right side panel.

2. Next, create a new action of the SQL Query type and use the {{ui.table.pageSize}} and {{ui.table.paginationOffset}} variables to control the data you need to load:

SELECT * FROM users LIMIT {{ui.table.pageSize}} OFFSET {{ui.table.paginationOffset}};

With these variables, you can configure your action to only load the page that the table requests, by sending the pageSize and paginationOffset variables to your API or Load table action.

1. Now, assign this action to the On Page Change trigger of the Table to ensure the data is reloaded with each table page navigation.

2. Finally, set the Table's Show loading setting to true while your SQL Query action is loading - add the {{actions.loadData.loading}} variable.

Done! Now the Table will display only the records for a specific page.

Cursor-based pagination

Let's review cursor-based pagination based on the Stripe API example. Say you want to select a list of customers from Stripe API. To do that, follow the instruction below:

1. For the Table component, select the Server side pagination checkbox in the right side panel.

2. Next, create a new action of the HTTP Request type and specify the {{ui.table.pageSize}} and {{ui.table.afterCursor}} variables in JS mode - Query Params.

const param = {
	limit: {{ui.table.pageSize}},
};
if ({{ui.table.afterCursor}}) {
	param.starting_after = {{ui.table.afterCursor}};
}

return param;

With these variables, you can configure your action to only load the page that the table requests, by sending pageSize and afterCursor variables to your API.

1. Now, in Table settings, set the following:

• {{_.last(actions.customers.data.data).id}} to the Next cursor field (the identifier used for the next set of results),

• {{actions.customers.data.has_more}} to the Has next page field to enable or disable the next page button according to API info, where actions.customers is the action we created in Step 2.

1. Assign your HTTP Request action to the On Page Change trigger of the table to ensure the data is reloaded with each table page navigation.

Total row count

By default, the Table doesn't know the total number of items and can't disable the Next page button if the limit is reached. To display the total item count and make the table more intuitive, you can set the Total row count setting. Based on it, the number of pages will be calculated and displayed according to the items per page.

To retrieve the total row count, you simply need to create an action that will retrieve the total number of items or get this info from the API you are using. For example, you can use an action of the SQL Query type:

SELECT COUNT(*) AS AMOUNT FROM orders;

When using a Load Table action type, you can obtain the row count using {{actions.loadData.res.total}}. In this case, you may not need the additional action to calculate the total number of records and you can use this property to show the pager.

Server-side filtering and sorting

When server-side pagination is enabled, table filters and sorting don't work automatically, as the Table cannot filter and sort the data while it's being loaded page by page.

Filtering

To configure server-side filters, you can use the {{ui.table.filters}} variable in your action to send this data to your API/SQL Query or Load Table action.

When using filters, make sure the SQL query is configured in a way that it returns all records when the filters are empty, instead of trying to search for empty records. For instance, for most SQL databases you would need to use a LIKE operator combined with the % sign, which represents zero, one, or multiple characters:

select
  *
from
  users
where
  users.name like CONCAT ('%', {{ ui.table.filters.name}}, '%')
limit
  {{ui.table.pageSize}}
offset
  {{ui.table.paginationOffset}}

And don't forget to assign the action with the filter variable to the On Filters Change trigger.

Sorting

To enable sorting, use the {{ui.table.sortColumn}} and {{ui.table.sortDirection}} variables in your action.

By default, dynamic sorting doesn't work as the Convert SQL queries to prepared statements option is enabled. You need to turn this setting OFF to allow dynamic sorting. But be cautious - disabling this setting can cause SQL injection!

After you disable the Prepared statement setting, your SQL Query will look like this:

select
  *
from
  users
where
  users.name like CONCAT ('%', '{{ ui.table.filters.name }}', '%')
order by
  {{ui.table.sortColumn ?? 'id'}} {{ui.table.sortDirection ?? 'asc'}}
limit
  {{ui.table.pageSize}}
offset
  {{ui.table.paginationOffset}}

You can set the default sort column and direction in JavaScript using the ?? operator. In our example here, it means - "if sortColumn is empty, use id column instead".

Notice how the name filter now requires quotes around the variable name:

CONCAT('%', '{{ ui.table.filters.name}}', '%')

As the query is not converted to prepared statements anymore, you need to add proper quotes around string values manually.

And don't forget to assign the action with the sorting variables to the On Sort Change trigger.

Troubleshooting

If everything is configured properly, but the action does not return the expected values, check the following:

• The action is assigned to all required triggers - On Page Change, On Filters Change, On Sort Change.

• The same action that handles filters and pagination is connected to the Data property of the Table component.

• If you're using dynamic sorting, make sure the Convert SQL queries to prepared statements setting is disabled and proper quotes are used around variables.

• Check the Payload tab, copy the query with the parameters, and manually run it against the database to ensure it is properly constructed.

• When setting your filters, make sure the query works in the following way: If a value is left blank or set to NULL, the query should retrieve all records based on that particular filter criterion, rather than just retrieving records with blank or NULL values for that criterion.

• If you notice that some of the variables are sent as 'null' or 'undefined' string values, adjust your variables interpolation to account conversion of these values to empty strings or other values using the ?? operator. For example: CONCAT('%', '{{ ui.table.filters.name ?? '' }}', '%').