Use the pg_type table to get valid type sizes for numeric types #61
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
jinzhu
reviewed
Sep 27, 2021
| "SELECT column_name, is_nullable, udt_name, character_maximum_length, "+ | ||
| "numeric_precision, numeric_precision_radix, numeric_scale, datetime_precision "+ | ||
| "FROM information_schema.columns WHERE table_catalog = ? AND table_schema = ? AND table_name = ?", | ||
| "numeric_precision, numeric_precision_radix, numeric_scale, datetime_precision, 8 * typlen "+ |
There was a problem hiding this comment.
From looking at the code, the value produced by migrator.ColumnType.Length() is expected to be in bits, so we either need to multiply by 8 here or in the Length() accessor. I thought doing it in the SQL expression would be less confusing.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
What did this pull request do?
This change uses the pg_type table to get the real size of numeric column types like
integerandbigintso that the automigration logic functions correctly.NOTE: this change may trigger column type changes because the previous logic wasn't detecting column type size at all for some types.
For example: in Gorm v1
intfields were treated as 32-bit values (integerin postgresql); however, in v2 they are now 64-bit values (bigint). Because gorm couldn't extract a type size from the type nameintegerit did not detect that a schema change was needed. With this change, these fields would be migrated fromintegertobigint.User Case Description
I described the issue that we were hitting in this issue in the main gorm repo: go-gorm/gorm#4641
In brief: there are some column types that are currently always triggering an
ALTER COLUMNduring migration because gorm misidentifies the current size of the database column. This PR fixes that issue.