user134391: Is that the process will go through all the blocks and find the block which contains the txid or there's an index table for all transactions?

user13866: This is not prescribed in the Bitcoin network protocols, of course. So each software developer is free to make their own choices.
Personally I think only the most inexperienced and naive developer would choose to read and re-read half a terabyte of data every time they need to retrieve a few bytes of data for a transaction. An index of any type is the obvious approach. There are numerous libraries and tools for this purpose.

134391: <p>Is that the process will go through all the blocks and find the block which contains the txid or there's an index table for all transactions?</p>
 13866: <p>This is not prescribed in the Bitcoin network protocols, of course. So each software developer is free to make their own choices.</p>
<p>Personally I think only the most inexperienced and naive developer would choose to read and re-read half a terabyte of data every time they need to retrieve a few bytes of data for a transaction. An index of any type is the obvious approach. There are numerous libraries and tools for this purpose.</p>
