What the max size of "Text" in motoko

72521 · June 16, 2021, 7:40am

i have a map like [(Text, Text)] in my motoko backend.
i want to know how big can “Text” store. what the max size can Text store
any where i can test or find those boundary.
also have same question about other type such as " Buffer"

nomeata · June 16, 2021, 9:42am

In theory, a single Text can be 2GB or so, but you’ll run into garbage collection limitation at this size.

So the size of a single Text is not limiting; the size of your total live data is more relevant.

72521 · June 16, 2021, 10:52am

During my testing
i call my canister with a size about 2mb. the canister will cause error.
and i got something like “ic0.msg_reply_data_append: application payload size (2621575) cannot be larger than 2097152”

2097152 is equal to 2mb

and i found MAX_INTER_CANISTER_PAYLOAD_IN_BYTES and some variables like max_reply_size here

github.com

dfinity/ic/blob/master/rs/system_api/src/lib.rs#L870

    
      
              size: u32,
              heap: &[u8],
          ) -> HypervisorResult<()> {
              match self.get_response_info() {
                  None => Err(self.error_for("ic0_msg_reply_data_append")),
                  Some((data, max_reply_size, response_status)) => match response_status {
                      ResponseStatus::NotRepliedYet => {
                          let payload_size = (data.len() + size as usize) as u64;
                          if payload_size > max_reply_size.get() {
                              let string = format!(
                                  "ic0.msg_reply_data_append: application payload size ({}) cannot be larger than {}",
                                  payload_size,
                                  max_reply_size,
                              );
                              return Err(ContractViolation(string));
                          }
                          data.extend_from_slice(valid_subslice("msg.reply", src, size, heap)?);
                          Ok(())
                      }
                      ResponseStatus::AlreadyReplied | ResponseStatus::JustRepliedWith(_) => {
                          Err(ContractViolation(

it seems limited to 2mb rather than 2GB.

can someone explain about those variables.

nomeata · June 16, 2021, 11:15am

Ah, but that is unrelated to the max size of Text in Motoko; you are facing the message size limit. But that affects only messages (you can store much more), and is independent of the programming language you are using.

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What the max size of "Text" in motoko

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