Merge branch 'selhorn-codeblock1' into 'master'

Codeblock language updates

See merge request gitlab-org/gitlab!24696

doc/development/sql.md

@@ -82,7 +82,7 @@ on the amount of data indexed).
 To keep naming of these indexes consistent please use the following naming
 pattern:
 
-```
+```plaintext
 index_TABLE_on_COLUMN_trigram
 ```
 

doc/development/testing_guide/best_practices.md

@@ -126,7 +126,7 @@ To resume the test run, press any key.
 
 For example:
 
-```
+```shell
 $ bin/rspec spec/features/auto_deploy_spec.rb:34
 Running via Spring preloader in process 8999
 Run options: include {:locations=>{"./spec/features/auto_deploy_spec.rb"=>[34]}}
@@ -147,7 +147,7 @@ Note: `live_debug` only works on JavaScript enabled specs.
 
 Run the spec with `CHROME_HEADLESS=0`, e.g.:
 
-```
+```shell
 CHROME_HEADLESS=0 bin/rspec some_spec.rb
 ```
 
@@ -242,7 +242,7 @@ This can be achieved by using
 [`before_all`](https://test-prof.evilmartians.io/#/before_all) hook
 from the [`test-prof` gem](https://rubygems.org/gems/test-prof).
 
-```
+```ruby
 let_it_be(:project) { create(:project) }
 let_it_be(:user) { create(:user) }
 
@@ -260,14 +260,14 @@ Note that if you modify an object defined inside a `let_it_be` block,
 then you will need to reload the object as needed, or specify the `reload`
 option to reload for every example.
 
-```
+```ruby
 let_it_be(:project, reload: true) { create(:project) }
 ```
 
 You can also specify the `refind` option as well to completely load a
 new object.
 
-```
+```ruby
 let_it_be(:project, refind: true) { create(:project) }
 ```
 
@@ -411,7 +411,7 @@ cause issues depending on the developer's local network. There are RSpec labels
 available in `spec/support/dns.rb` which you can apply to tests if you need to
 bypass the DNS stubbing, e.g.:
 
-```
+```ruby
 it "really connects to Prometheus", :permit_dns do
 ```
 

doc/development/testing_guide/review_apps.md

@@ -251,7 +251,7 @@ Any secrets or config maps older than 5 days are suspect and should be deleted.
 
 **Useful commands:**
 
-```
+```shell
 # List secrets and config maps ordered by created date
 › kubectl get secret,cm --sort-by='{.metadata.creationTimestamp}' | grep 'review-'
 
@@ -294,7 +294,7 @@ This in turn prevented other components of the Review App to properly start
 After some digging, we found that new mounts were failing, when being performed
 with transient scopes (e.g. pods) of `systemd-mount`:
 
-```
+```plaintext
 MountVolume.SetUp failed for volume "dns-gitlab-review-app-external-dns-token-sj5jm" : mount failed: exit status 1
 Mounting command: systemd-run
 Mounting arguments: --description=Kubernetes transient mount for /var/lib/kubelet/pods/06add1c3-87b4-11e9-80a9-42010a800107/volumes/kubernetes.io~secret/dns-gitlab-review-app-external-dns-token-sj5jm --scope -- mount -t tmpfs tmpfs /var/lib/kubelet/pods/06add1c3-87b4-11e9-80a9-42010a800107/volumes/kubernetes.io~secret/dns-gitlab-review-app-external-dns-token-sj5jm
@@ -342,7 +342,7 @@ clean up the list of non-`Running` pods.
 Following is a command to delete Review Apps based on their last deployment date
 (current date was June 6th at the time) with
 
-```
+```shell
 helm ls -d | grep "Jun  4" | cut -f1 | xargs helm delete --purge
 ```
 

doc/development/understanding_explain_plans.md

@@ -14,7 +14,7 @@ WHERE visibility_level IN (0, 20);
 
 When running this on GitLab.com, we are presented with the following output:
 
-```
+```sql
 Aggregate  (cost=922411.76..922411.77 rows=1 width=8)
   ->  Seq Scan on projects  (cost=0.00..908044.47 rows=5746914 width=0)
         Filter: (visibility_level = ANY ('{0,20}'::integer[]))
@@ -35,7 +35,7 @@ WHERE visibility_level IN (0, 20);
 
 This will produce:
 
-```
+```sql
 Aggregate  (cost=922420.60..922420.61 rows=1 width=8) (actual time=3428.535..3428.535 rows=1 loops=1)
   ->  Seq Scan on projects  (cost=0.00..908053.18 rows=5746969 width=0) (actual time=0.041..2987.606 rows=5746940 loops=1)
         Filter: (visibility_level = ANY ('{0,20}'::integer[]))
@@ -69,7 +69,7 @@ WHERE visibility_level IN (0, 20);
 
 This will then produce:
 
-```
+```sql
 Aggregate  (cost=922420.60..922420.61 rows=1 width=8) (actual time=3428.535..3428.535 rows=1 loops=1)
   Buffers: shared hit=208846
   ->  Seq Scan on projects  (cost=0.00..908053.18 rows=5746969 width=0) (actual time=0.041..2987.606 rows=5746940 loops=1)
@@ -105,7 +105,7 @@ aggregate(
 Nodes are indicated using a `->` followed by the type of node taken. For
 example:
 
-```
+```sql
 Aggregate  (cost=922411.76..922411.77 rows=1 width=8)
   ->  Seq Scan on projects  (cost=0.00..908044.47 rows=5746914 width=0)
         Filter: (visibility_level = ANY ('{0,20}'::integer[]))
@@ -119,7 +119,7 @@ above it.
 
 Nested nodes will look like this:
 
-```
+```sql
 Aggregate  (cost=176.97..176.98 rows=1 width=8) (actual time=0.252..0.252 rows=1 loops=1)
   Buffers: shared hit=155
   ->  Nested Loop  (cost=0.86..176.75 rows=87 width=0) (actual time=0.035..0.249 rows=36 loops=1)
@@ -142,7 +142,7 @@ Here we first perform two separate "Index Only" scans, followed by performing a
 Each node in a plan has a set of associated statistics, such as the cost, the
 number of rows produced, the number of loops performed, and more. For example:
 
-```
+```sql
 Seq Scan on projects  (cost=0.00..908044.47 rows=5746914 width=0)
 ```
 
@@ -157,7 +157,7 @@ influences the costs depends on a variety of settings, such as `seq_page_cost`,
 `cpu_tuple_cost`, and various others.
 The format of the costs field is as follows:
 
-```
+```sql
 STARTUP COST..TOTAL COST
 ```
 
@@ -169,7 +169,7 @@ When using `EXPLAIN ANALYZE`, these statistics will also include the actual time
 (in milliseconds) spent, and other runtime statistics (e.g. the actual number of
 produced rows):
 
-```
+```sql
 Seq Scan on projects  (cost=0.00..908053.18 rows=5746969 width=0) (actual time=0.041..2987.606 rows=5746940 loops=1)
 ```
 
@@ -181,7 +181,7 @@ Using `EXPLAIN (ANALYZE, BUFFERS)` will also give us information about the
 number of rows removed by a filter, the number of buffers used, and more. For
 example:
 
-```
+```sql
 Seq Scan on projects  (cost=0.00..908053.18 rows=5746969 width=0) (actual time=0.041..2987.606 rows=5746940 loops=1)
   Filter: (visibility_level = ANY ('{0,20}'::integer[]))
   Rows Removed by Filter: 65677
@@ -245,7 +245,7 @@ Sorts the input rows as specified using an `ORDER BY` statement.
 A nested loop will execute its child nodes for every row produced by a node that
 precedes it. For example:
 
-```
+```sql
 ->  Nested Loop  (cost=0.86..176.75 rows=87 width=0) (actual time=0.035..0.249 rows=36 loops=1)
       Buffers: shared hit=155
       ->  Index Only Scan using users_pkey on users users_1  (cost=0.43..4.95 rows=87 width=4) (actual time=0.029..0.123 rows=36 loops=1)
@@ -287,7 +287,7 @@ WHERE twitter != '';
 
 This will produce the following plan:
 
-```
+```sql
 Aggregate  (cost=845110.21..845110.22 rows=1 width=8) (actual time=1271.157..1271.158 rows=1 loops=1)
   Buffers: shared hit=202662
   ->  Seq Scan on users  (cost=0.00..844969.99 rows=56087 width=0) (actual time=0.019..1265.883 rows=51833 loops=1)
@@ -312,7 +312,7 @@ on the `users` table that we might be able to use. We can obtain this
 information by running `\d users` in a `psql` console, then scrolling down to
 the `Indexes:` section:
 
-```
+```sql
 Indexes:
     "users_pkey" PRIMARY KEY, btree (id)
     "users_confirmation_token_key" UNIQUE CONSTRAINT, btree (confirmation_token)
@@ -347,7 +347,7 @@ CREATE INDEX CONCURRENTLY twitter_test ON users (twitter);
 If we now re-run our query using `EXPLAIN (ANALYZE, BUFFERS)` we get the
 following plan:
 
-```
+```sql
 Aggregate  (cost=61002.82..61002.83 rows=1 width=8) (actual time=297.311..297.312 rows=1 loops=1)
   Buffers: shared hit=51854 dirtied=19
   ->  Index Only Scan using twitter_test on users  (cost=0.43..60873.13 rows=51877 width=0) (actual time=279.184..293.532 rows=51833 loops=1)
@@ -364,7 +364,7 @@ seconds. However, we still use 51,854 buffers, which is about 400 MB of memory.
 300 milliseconds is also quite slow for such a simple query. To understand why
 this query is still expensive, let's take a look at the following:
 
-```
+```sql
 Index Only Scan using twitter_test on users  (cost=0.43..60873.13 rows=51877 width=0) (actual time=279.184..293.532 rows=51833 loops=1)
   Filter: ((twitter)::text <> ''::text)
   Rows Removed by Filter: 2487830
@@ -401,7 +401,7 @@ CREATE INDEX CONCURRENTLY twitter_test ON users (twitter) WHERE twitter != '';
 
 Once created, if we run our query again we will be given the following plan:
 
-```
+```sql
 Aggregate  (cost=1608.26..1608.27 rows=1 width=8) (actual time=19.821..19.821 rows=1 loops=1)
   Buffers: shared hit=44036
   ->  Index Only Scan using twitter_test on users  (cost=0.41..1479.71 rows=51420 width=0) (actual time=0.023..15.514 rows=51833 loops=1)
@@ -438,7 +438,7 @@ WHERE visibility_level IN (0, 20);
 
 The output of `EXPLAIN (ANALYZE, BUFFERS)` is as follows:
 
-```
+```sql
 Aggregate  (cost=922420.60..922420.61 rows=1 width=8) (actual time=3428.535..3428.535 rows=1 loops=1)
   Buffers: shared hit=208846
   ->  Seq Scan on projects  (cost=0.00..908053.18 rows=5746969 width=0) (actual time=0.041..2987.606 rows=5746940 loops=1)
@@ -451,7 +451,7 @@ Execution time: 3428.596 ms
 
 Looking at the output we see the following Filter:
 
-```
+```sql
 Filter: (visibility_level = ANY ('{0,20}'::integer[]))
 Rows Removed by Filter: 65677
 ```
@@ -481,7 +481,7 @@ ORDER BY visibility_level ASC;
 
 For GitLab.com this produces:
 
-```
+```sql
  visibility_level | amount
 ------------------+---------
                 0 | 5071325
@@ -528,7 +528,7 @@ interacted with somehow?
 Fortunately, GitLab has an answer for this, and it's a table called
 `user_interacted_projects`. This table has the following schema:
 
-```
+```sql
 Table "public.user_interacted_projects"
    Column   |  Type   | Modifiers
 ------------+---------+-----------
@@ -564,7 +564,7 @@ What we do here is the following:
 
 If we run this query we get the following plan:
 
-```
+```sql
  Aggregate  (cost=871.03..871.04 rows=1 width=8) (actual time=9.763..9.763 rows=1 loops=1)
    ->  Nested Loop  (cost=0.86..870.52 rows=203 width=0) (actual time=1.072..9.748 rows=143 loops=1)
          ->  Index Scan using index_user_interacted_projects_on_user_id on user_interacted_projects  (cost=0.43..160.71 rows=205 width=4) (actual time=0.939..2.508 rows=145 loops=1)
@@ -580,7 +580,7 @@ If we run this query we get the following plan:
 Here it only took us just under 10 milliseconds to get the data. We can also see
 we're retrieving far fewer projects:
 
-```
+```sql
 Index Scan using projects_pkey on projects  (cost=0.43..3.45 rows=1 width=4) (actual time=0.049..0.050 rows=1 loops=145)
   Index Cond: (id = user_interacted_projects.project_id)
   Filter: (visibility_level = ANY ('{0,20}'::integer[]))
@@ -592,14 +592,14 @@ Here we see we perform 145 loops (`loops=145`), with every loop producing 1 row
 
 If we look at the plan we also see our costs are very low:
 
-```
+```sql
 Index Scan using projects_pkey on projects  (cost=0.43..3.45 rows=1 width=4) (actual time=0.049..0.050 rows=1 loops=145)
 ```
 
 Here our cost is only 3.45, and it only takes us 0.050 milliseconds to do so.
 The next index scan is a bit more expensive:
 
-```
+```sql
 Index Scan using index_user_interacted_projects_on_user_id on user_interacted_projects  (cost=0.43..160.71 rows=205 width=4) (actual time=0.939..2.508 rows=145 loops=1)
 ```
 
@@ -609,7 +609,7 @@ Here the cost is 160.71 (`cost=0.43..160.71`), taking about 2.5 milliseconds
 The most expensive part here is the "Nested Loop" that acts upon the result of
 these two index scans:
 
-```
+```sql
 Nested Loop  (cost=0.86..870.52 rows=203 width=0) (actual time=1.072..9.748 rows=143 loops=1)
 ```
 
@@ -687,13 +687,13 @@ Execution time: 0.113 ms
 `/chatops` slash command](chatops_on_gitlabcom.md).
 You can use chatops to get a query plan by running the following:
 
-```
+```sql
 /chatops run explain SELECT COUNT(*) FROM projects WHERE visibility_level IN (0, 20)
 ```
 
 Visualising the plan using <https://explain.depesz.com/> is also supported:
 
-```
+```sql
 /chatops run explain --visual SELECT COUNT(*) FROM projects WHERE visibility_level IN (0, 20)
 ```
 
@@ -701,7 +701,7 @@ Quoting the query is not necessary.
 
 For more information about the available options, run:
 
-```
+```sql
 /chatops run explain --help
 ```
 
@@ -714,31 +714,31 @@ For example, in order to test new index you can do the following:
 
 Create the index:
 
-```
+```sql
 exec CREATE INDEX index_projects_marked_for_deletion ON projects (marked_for_deletion_at) WHERE marked_for_deletion_at IS NOT NULL
 ```
 
 Analyze the table to update its statistics:
 
-```
+```sql
 exec ANALYZE projects
 ```
 
 Get the query plan:
 
-```
+```sql
 explain SELECT * FROM projects WHERE marked_for_deletion_at < CURRENT_DATE
 ```
 
 Once done you can rollback your changes:
 
-```
+```sql
 reset
 ```
 
 For more information about the available options, run:
 
-```
+```sql
 help
 ```