* migrations: add if statements for some queries
* add better checks to upgrade posts v6 migration
* use "is null" instead of "= null"
* fix down script for users v6
* reflect review comments
Installing tools via go get is deprecated since Go 1.17,
and directly installing a version via go install is recommended.
We remove the go.tools.mod file as it's no longer the right
pattern.
```release-note
NONE
```
* Update morph dependency to use a newer version
* remove timeout check for migrations statements
* store/sqlstore: reset timeout for mysql while creating db for migrations
* update morph to v0.2.1
* feat: add Type/EditAt field to PostImportData
* test: add tests
* feat: add Type/EditAt field to ReplyImportData
* chore: fix lint error
* test: fix failed tests
* test: refactoring
* test: fix how to assertion
* test: fix failed case which depends on accidental order of replies
- Fixed the Makefile command so that it can be run in CI
- Changed to go install to make it compatible with >1.16 versions.
- Removed unnecessary lines in go.tools.mod now that we aren't using that.
```release-note
NONE
```
Due to the store method having named returns, the variable
was getting set to nil instead of being an empty slice.
We missed this during code review.
https://mattermost.atlassian.net/browse/MM-40594
```release-note
NONE
```
* MM-40799: Improve ReplyCount query
This PR optimizes the reply count query to use only
the indexed column to count the rows rather than using
the ID column. This results in an index-only scan
rather than an index scan. As a result, the query
can be satisfied directly by scanning the index
and there is no need to touch the heap.
Count(*) also gives the same result, but is not recommended
as it also verifies non-null columns and can take slightly
longer.
Before:
```
explain analyze SELECT p.*, (SELECT COUNT(Posts.Id) FROM Posts WHERE Posts.RootId = (CASE WHEN p.RootId = '' THEN p.Id ELSE p.RootId END) AND Posts.DeleteAt = 0) AS ReplyCount FROM Posts p WHERE (CreateAt < (SELECT CreateAt FROM Posts WHERE Id = 'bguxt6zzcjytpffgza3dc7xody') AND p.ChannelId = '5xmynf36cinrzksuzhq7my1nbc' AND DeleteAt = 0) ORDER BY p.ChannelId, DeleteAt, CreateAt DESC LIMIT 30 OFFSET 0;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=9.14..130616.04 rows=30 width=922) (actual time=19.208..19.454 rows=30 loops=1)
InitPlan 2 (returns $2)
-> Index Scan using posts_pkey on posts posts_1 (cost=0.56..8.58 rows=1 width=8) (actual time=0.028..0.030 rows=1 loops=1)
Index Cond: ((id)::text = 'bguxt6zzcjytpffgza3dc7xody'::text)
-> Index Scan Backward using idx_posts_channel_id_delete_at_create_at on posts p (cost=0.56..2720977.61 rows=625 width=922) (actual time=0.075..0.317 rows=30 loops=1)
Index Cond: (((channelid)::text = '5xmynf36cinrzksuzhq7my1nbc'::text) AND (deleteat = 0) AND (createat < $2))
SubPlan 1
-> Aggregate (cost=4349.49..4349.50 rows=1 width=8) (actual time=0.007..0.007 rows=1 loops=30)
-> Index Scan using idx_posts_root_id_delete_at on posts (cost=0.56..4346.36 rows=1253 width=27) (actual time=0.007..0.007 rows=0 loops=30)
Index Cond: (((rootid)::text = (CASE WHEN ((p.rootid)::text = ''::text) THEN p.id ELSE p.rootid END)::text) AND (deleteat = 0))
```
After:
```
explain analyze SELECT p.*, (SELECT COUNT(Posts.RootId) FROM Posts WHERE Posts.RootId = (CASE WHEN p.RootId = '' THEN p.Id ELSE p.RootId END) AND Posts.DeleteAt = 0) AS ReplyCount FROM Posts p WHERE (CreateAt < (SELECT CreateAt FROM Posts WHERE Id = 'bguxt6zzcjytpffgza3dc7xody') AND p.ChannelId = '5xmynf36cinrzksuzhq7my1nbc' AND DeleteAt = 0) ORDER BY p.ChannelId, DeleteAt, CreateAt DESC LIMIT 30 OFFSET 0;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=9.14..130616.04 rows=30 width=922) (actual time=12.936..13.188 rows=30 loops=1)
InitPlan 2 (returns $2)
-> Index Scan using posts_pkey on posts posts_1 (cost=0.56..8.58 rows=1 width=8) (actual time=0.029..0.030 rows=1 loops=1)
Index Cond: ((id)::text = 'bguxt6zzcjytpffgza3dc7xody'::text)
-> Index Scan Backward using idx_posts_channel_id_delete_at_create_at on posts p (cost=0.56..2720977.61 rows=625 width=922) (actual time=0.076..0.324 rows=30 loops=1)
Index Cond: (((channelid)::text = '5xmynf36cinrzksuzhq7my1nbc'::text) AND (deleteat = 0) AND (createat < $2))
SubPlan 1
-> Aggregate (cost=4349.49..4349.50 rows=1 width=8) (actual time=0.008..0.008 rows=1 loops=30)
-> Index Only Scan using idx_posts_root_id_delete_at on posts (cost=0.56..4346.36 rows=1253 width=8) (actual time=0.007..0.007 rows=0 loops=30)
Index Cond: ((rootid = (CASE WHEN ((p.rootid)::text = ''::text) THEN p.id ELSE p.rootid END)::text) AND (deleteat = 0))
Heap Fetches: 14
```
https://mattermost.atlassian.net/browse/MM-40799
```release-note
NONE
```
* Use COUNT(*) for faster
```release-note
NONE
```
This query deals with posts already created,
and it was originally already querying replica.
In recent performance investigations, this came up
a lot of times. I believe the change to query master
was unintentional.
```release-note
NONE
```
