Execute NOT NULL with ADD COLUMN in PG11+ #39
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One of the performance improvements in Postgres 11 was executing an `ADD COLUMN ... NOT NULL` without needing a table rewrite. This is now a safe operation in PG11+, and we can avoid adding backwards-compatible safe version with a statement timeout that can fail in some cases. https://www.postgresql.org/docs/release/11.0/
ThHareau
approved these changes
Mar 31, 2021
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No worries! Thanks for taking a look! :) |
ThHareau
reviewed
Apr 2, 2021
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| def add_column(table_name, column_name, type, **options) | ||
| need_default_value_backfill = SafePgMigrations.pg_version_num < PG_11_VERSION_NUM | ||
| apply_not_null_constraint_separately = SafePgMigrations.pg_version_num < PG_11_VERSION_NUM | ||
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| default = options.delete(:default) if need_default_value_backfill | ||
| null = options.delete(:null) | ||
| null = options.delete(:null) if apply_not_null_constraint_separately |
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Actually, now that null is natively handled by ActiveRecord's add_column, we do nothing if PG version is recent enough. We could simplify a lot this method:
def add_column(table_name, column_name, type, **options)
return super if SafePgMigrations.pg_version_num >= PG_11_VERSION_NUM
default = options.delete(:default)
null = options.delete(:null)
# ...
endWould you like to handle this refactoring as well?
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That totally makes sense! I can make this change shortly.
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Done! I also added a few more tests for the older version of Postgres to cover a few more variations of arguments for the older versions since I was changing that logic a little more.
Let me know if we need to do anything else here!
This simplifies the if checks enough that we no longer have to ignore the Rubocop complaints about complexity.
ThHareau
approved these changes
Apr 6, 2021
| @@ -10,10 +10,10 @@ module StatementInsurer | |||
| end | |||
| end | |||
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| def add_column(table_name, column_name, type, **options) # rubocop:disable Metrics/CyclomaticComplexity | |||
| need_default_value_backfill = SafePgMigrations.pg_version_num < PG_11_VERSION_NUM | |||
| def add_column(table_name, column_name, type, **options) | |||
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That's great to see this method disable removed
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One of the performance improvements in Postgres 11 was executing an
ADD COLUMN ... NOT NULLwithout needing a table rewrite. This is now a safe operation in PG11+, and we can avoid adding backwards-compatible safe version with a statement timeout that can fail in some cases.https://www.postgresql.org/docs/release/11.0/
Fixes #37.