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[AP-591] Use SHOW SCHEMAS|TABLES|COLUMNS instead of INFORMATION_SCHEMA #14
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Summary
This PR refactoring the code to use
SHOW SCHEMAS|TABLES|COLUMNSqueries instead ofINFORMATION_SCHEMA. Information schema queries are slow in general and can cause failing parallel running taps withsnowflake.connector.errors.ProgrammingError: 090030 (22000): Information schema query returned too much data. Please repeat query with more selective predicates.Solution
This is in sync with the same change in
pipelinewise-target-snowflake1.6.1 at transferwise/pipelinewise-target-snowflake#67Cons:
SHOW SCHEMAS|TABLES|COLUMNSreturns max 10k rows.If a
SHOWquery returns more than 9999 records then an exception will be raised. This is a limitation ofSHOW COLUMNSbut 10k rows should be enough for hundreds of average length tables. If 10k columns not enough then we can still queryINFORMATION_SCHEMAas a fallback method but this is not in scope of this PR