Hello all I am trying to understand Accumulo scan workflow. I've checked the official docs but I couldn't understand the workflow properly. Could anyone please tell me if I'm on the right track? For example if I want to scan rows in the range e-g in a table mytable which is sharded across 3 nodes in the cluster:
Step1: Client connects to the Zookeeper and gets the location of the root tablet. Step2: Client connects to tserver with the root tablet and gets the location of mytable. the row distribution is as follows: tserver1 tserver2 tserver3 a-g h-k l-z Step3: Client connects to tserver1 and tserver2. Step4: tservers merge and sort data from in-memory maps, minc files and majc files, apply versioning iterator, seek the requested range and send data back to the client. Is this how a scan works? Also, I have some doubts: 1. Where is the data from tserver1 and tserver2 merged? 2. when and how are custom iterators applied? Also, if there is any resource explaining this, please point me to it. I've found some slides but no detailed explanation. Best regards, Yamini Joshi
