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chinni dchinni d 

what will happen if we set <apex:page readonly="true"?

Himanshu ParasharHimanshu Parashar
Hi Chinni,

Read only attribute is a Boolean value that enables read-only mode for a Visualforce page. In read-only mode, a page may not execute any DML operations, but the limit on the number of records retrieved is relaxed from 50,000 to 1 million rows. It also increases the number of items in a collection that can be handled by iteration components, from 1,000 to 10,000. If not specified, this value defaults to false.


Thanks,
Himanshu

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TabrezTabrez
Hi Chinni,

Visualforce pages that use read-only mode for the entire page can’t use data manipulation language (DML) operations, they can call getter, setter, and action methods which affect form and other user interface elements on the page, make additional read-only queries, and so on.

-- Normally, queries for a single Visualforce page request may not retrieve more than 50,000 rows. In read-only mode, this limit is relaxed to allow querying up to 1 million rows.

-- the readOnly attribute also increases the maximum number of items in a collection that can be iterated over using components such as <apex:dataTable>, <apex:dataList>, and <apex:repeat>. This limit increased from1,000 items to 10,000.

For more details along with a code to understand please check below link:

https://developer.salesforce.com/docs/atlas.en-us.pages.meta/pages/pages_controller_readonly_context_pagelevel.htm


Regards,
TabreZ