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authorGitLab Bot <gitlab-bot@gitlab.com>2021-07-02 18:07:36 +0300
committerGitLab Bot <gitlab-bot@gitlab.com>2021-07-02 18:07:36 +0300
commite61f798b74e8e18fca7239fd01802182479bfcfc (patch)
tree4a49b062d8df2ffe3e6e8a07d2aadc034acb9092 /doc/development/sql.md
parentafbfbfc87abfa006f1d369fdf9c740eb1c826808 (diff)
Add latest changes from gitlab-org/gitlab@master
Diffstat (limited to 'doc/development/sql.md')
-rw-r--r--doc/development/sql.md12
1 files changed, 6 insertions, 6 deletions
diff --git a/doc/development/sql.md b/doc/development/sql.md
index a98645cfcae..ddca88cb9bb 100644
--- a/doc/development/sql.md
+++ b/doc/development/sql.md
@@ -70,7 +70,7 @@ WHERE title ILIKE '%Draft:%';
Because the value for `ILIKE` starts with a wildcard the database is not able to
use an index as it doesn't know where to start scanning the indexes.
-Luckily, PostgreSQL _does_ provide a solution: trigram GIN indexes. These
+Luckily, PostgreSQL _does_ provide a solution: trigram Generalized Inverted Index (GIN) indexes. These
indexes can be created as follows:
```sql
@@ -261,9 +261,9 @@ from `ActiveRecord::Base`.
## Use UNIONs
-UNIONs aren't very commonly used in most Rails applications but they're very
-powerful and useful. In most applications queries tend to use a lot of JOINs to
-get related data or data based on certain criteria, but JOIN performance can
+`UNION`s aren't very commonly used in most Rails applications but they're very
+powerful and useful. Queries tend to use a lot of `JOIN`s to
+get related data or data based on certain criteria, but `JOIN` performance can
quickly deteriorate as the data involved grows.
For example, if you want to get a list of projects where the name contains a
@@ -279,7 +279,7 @@ OR namespaces.name ILIKE '%gitlab%';
```
Using a large database this query can easily take around 800 milliseconds to
-run. Using a UNION we'd write the following instead:
+run. Using a `UNION` we'd write the following instead:
```sql
SELECT projects.*
@@ -301,7 +301,7 @@ This doesn't mean you should start using UNIONs everywhere, but it's something
to keep in mind when using lots of JOINs in a query and filtering out records
based on the joined data.
-GitLab comes with a `Gitlab::SQL::Union` class that can be used to build a UNION
+GitLab comes with a `Gitlab::SQL::Union` class that can be used to build a `UNION`
of multiple `ActiveRecord::Relation` objects. You can use this class as
follows: