Issues and Suggestions

Spanner migration tool scans through the generated spanner schema and notifies the user of any warnings or errors 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. Errors
  3. Suggestions

Warnings

  • Detection of an auto-increment key in source database because auto-increments are currently not supported for all source databases.
  • 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
  • Auto Increment has been converted to Sequence, set Ignore Range or Start with Counter to avoid duplicate value errors
  • Dropping unsupported default values during schema migration.

Errors

  • Detection of unsupported check constraints in spanner.
  • Detection of invalid default values in spanner added during column modification.
  • Data type mismatch of referenced column in check constraints.
  • Referenced column in check constraints not found.
  • Function referenced in check constraints is not found.

Suggestions

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