Why am I seeing only one transaction per getting mined per contract per block?

Question

I am creating large contracts A and T (not real names) that represent actual business needs and these contract have several setters (A.setXXX, A.setYYY, T.setZZZ ...) functions to initialize the storage of the contracts.

I am working on the pattern that 1) first I create the contract with the basing info and then the end user (java script) set the other info from outside with several transactions.

I then realise that each transaction on the same contract are mined one at at time. If I have in javascript

A.setXXX();
A.setYYY();

then it takes 2 blocks to have them both processed

However if I call

A.setXXX();
T.setZZZ();

Both transactions are included in the same block

So i conclude that the miner only take one transation for each object and discard the other transactions for later processing.

My questions are:

• Is this rule normal?
• What is the reasoning?
• Is there a way around this?
• Am I using an incorrect pattern for populating large contract?

Thanks for advises

Note that I selected this pattern because I could find solution to call a transaction with a large structure as parameters.

Answer 1

A miner will usually mine multiple transactions in the same block, and they will be executed in order, regardless whether they access the same contract or not.

If your setters are using a lot of gas, it may be that the two calls to A in combination are using more than the block gas limit (or the remaining gas in the block if there are already other transactions included in it), in which case they can't both be included in the same block. If T uses less gas than your second call to A, it may be possible to squeeze that in where a second call to A wouldn't fit.