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authorValery Sizov <valery@gitlab.com>2017-05-18 11:35:59 +0300
committerValery Sizov <valery@gitlab.com>2017-05-18 11:35:59 +0300
commitcf9d9d865daee2f3c0dd549afa3b168a8e1e679e (patch)
tree77eb3bee305a9abca3ef92c457959e5ac2079794
parenta49337727be1e28c29ad19b310fa2eb2df828c91 (diff)
downloadgitlab-ce-cf9d9d865daee2f3c0dd549afa3b168a8e1e679e.tar.gz
[Migration guide] Add note about prefering change_column_null over change_columnchange_migration_style_guide
-rw-r--r--doc/development/what_requires_downtime.md2
1 files changed, 2 insertions, 0 deletions
diff --git a/doc/development/what_requires_downtime.md b/doc/development/what_requires_downtime.md
index 8da6ad684f5..c4830322fa8 100644
--- a/doc/development/what_requires_downtime.md
+++ b/doc/development/what_requires_downtime.md
@@ -139,6 +139,8 @@ Adding or removing a NOT NULL clause (or another constraint) can typically be
done without requiring downtime. However, this does require that any application
changes are deployed _first_. Thus, changing the constraints of a column should
happen in a post-deployment migration.
+NOTE: Avoid using `change_column` as it produces inefficient query because it re-defines
+the whole column type. For example, to add a NOT NULL constraint, prefer `change_column_null `
## Changing Column Types