Issues and Suggestions

Spanner migration tool scans through the generated spanner schema and notifies the user of any warnings encountered. It also makes intelligent suggestions to the user which would help them utilize the spanner capabilities to the fullest.

Table of contents
  1. Warnings
  2. Suggestions


  • Detection of an auto-increment key in source database because auto-increments are currently not supported in spanner
  • Spanner data type consuming more storage than source data type
  • Redundant indexes
  • Addition of synthetic primary key - synth_id
  • Hotspotting due to timestamp or auto-increment keys


  • Modifications related to converting a table into an interleaved one
  • Converting an index to interleaved index