Copy CSV and Storage TODOs for Phase 1

[semihsalihoglu-uw]

Functionality

• Support for list data type
• Replace robin_hood_node_id map to use our hash_index. Two main things need to be done:
  1. Hash_Index needs to support parallel updates.
  2. We need to replace robin_hood_node_id map. We should ensure that after the index is constructed, we should save it to disk and then in later parts of the loader access it through the BufferManager.
• Allow copying a node/rel csv file with or without header.

Usability

• Progress Reporting Mechanism: This piece of code works nicely: https://stackoverflow.com/questions/14539867/how-to-display-a-progress-indicator-in-pure-c-c-cout-printf. We need to wrap it around a updateProgress function, do some computation to compute progress percentages based on the number of files and lines in each file and then call updateProgress in different parts of the code. [Loader progress bar #507 ]
• When large strings are being inserted, give a warning instead of failing. => Just take the prefix 4096 char for now.
• If for a relationship, there is single nodeLabel and a single destination nodeLabel, then do not require relationship files to contain a START_ID_LABEL and END_ID_LABEL fields.
• Verify each CSV header as the first step and if there is something wrong, then error early with a proper error message. => Be graceful with capitalization but let's not accept arbitrary column names that don't match the schema.