Merge pull request #122 from Altinity/sphoorti

Updated broken webinar links, added internal links, etc.

content/en/altinity-kb-schema-design/materialized-views/_index.md

@@ -1,15 +1,24 @@
 ---
-title: "MATERIALIZED VIEWS"
+title: "ClickHouse® MATERIALIZED VIEWS"
 linkTitle: "MATERIALIZED VIEWS"
 description: >
-    MATERIALIZED VIEWS
+    Making the most of this powerful ClickHouse® feature
+keywords: 
+   - clickhouse materialized view
+   - create materialized view clickhouse
 ---
 
-MATERIALIZED VIEWs in ClickHouse® behave like AFTER INSERT TRIGGER to the left-most table listed in their SELECT statement and never read data from disk. Only rows that are placed to the RAM buffer by INSERT are read.
+ClickHouse® MATERIALIZED VIEWs behave like AFTER INSERT TRIGGER to the left-most table listed in their SELECT statement and never read data from disk. Only rows that are placed to the RAM buffer by INSERT are read.
 
 ## Useful links
 
-* ClickHouse and the magic of materialized views. Basics explained with examples: [webinar recording](https://altinity.com/webinarspage/2019/6/26/clickhouse-and-the-magic-of-materialized-views)
+* ClickHouse Materialized Views Illuminated, Part 1:
+  * [Blog post](https://altinity.com/blog/clickhouse-materialized-views-illuminated-part-1)
+  * [Webinar recording](https://altinity.com/blog/clickhouse-materialized-views-illuminated-part-1)
+  * [Slides](https://altinity.com/blog/clickhouse-materialized-views-illuminated-part-1)
+* ClickHouse Materialized Views Illuminated, Part 2: 
+  * [Blog post](https://altinity.com/blog/clickhouse-materialized-views-illuminated-part-2)
+  * [Webinar recording](https://www.youtube.com/watch?v=THDk625DGsQ)
 * Everything you should know about materialized views - [annotated presentation](https://den-crane.github.io/Everything_you_should_know_about_materialized_views_commented.pdf)
 * Very detailed information about internals: [video](https://youtu.be/ckChUkC3Pns?t=9353)
 * One more [presentation](https://github.com/ClickHouse/clickhouse-presentations/blob/master/meetup47/materialized_views.pdf)

content/en/altinity-kb-setup-and-maintenance/altinity-kb-check-replication-ddl-queue.md

@@ -1,13 +1,18 @@
 ---
-title: "Replication and DDL queue problems"
+title: "ClickHouse® Replication and DDL queue problems"
 linkTitle: "Replication and DDL queue problems"
 description: >
-    This article describes how to detect possible problems in the `replication_queue` and `distributed_ddl_queue` and how to troubleshoot.
+    Finding and troubleshooting  problems in the `replication_queue` and `distributed_ddl_queue`
+keywords: 
+   - clickhouse replication	
+   - clickhouse ddl
+   - clickhouse check replication status
+   - clickhouse replication queue
 ---
 
-# How to check replication problems:
+# How to check ClickHouse® replication problems:
 
-1. check `system.replicas` first, cluster-wide. It allows to check if the problem is local to some replica or global, and allows to see the exception.
+1. Check `system.replicas` first, cluster-wide. It allows to check if the problem is local to some replica or global, and allows to see the exception.
    allows to answer the following questions:
    - Are there any ReadOnly replicas?
    - Is there the connection to zookeeper active?
@@ -90,7 +95,7 @@ FORMAT TSVRaw;
 
 Sometimes due to crashes, zookeeper split brain problem or other reasons some of the tables can be in Read-Only mode. This allows SELECTS but not INSERTS. So we need to do DROP / RESTORE replica procedure.
 
-Just to be clear, this procedure **will not delete any data**, it will just re-create the metadata in zookeeper with the current state of the ClickHouse replica.
+Just to be clear, this procedure **will not delete any data**, it will just re-create the metadata in zookeeper with the current state of the [ClickHouse replica](/altinity-kb-setup-and-maintenance/altinity-kb-data-migration/add_remove_replica/).
 
 ```sql
 DETACH TABLE table_name;  -- Required for DROP REPLICA
@@ -171,7 +176,7 @@ restore_replica "$@"
 
 ### Stuck DDL tasks in the distributed_ddl_queue
 
-Sometimes DDL tasks (the ones that use ON CLUSTER) can get stuck in the `distributed_ddl_queue` because the replicas can overload if multiple DDLs (thousands of CREATE/DROP/ALTER) are executed at the same time. This is very normal in heavy ETL jobs.This can be detected by checking the `distributed_ddl_queue` table and see if there are tasks that are not moving or are stuck for a long time.
+Sometimes [DDL tasks](/altinity-kb-setup-and-maintenance/altinity-kb-ddlworker/) (the ones that use ON CLUSTER) can get stuck in the `distributed_ddl_queue` because the replicas can overload if multiple DDLs (thousands of CREATE/DROP/ALTER) are executed at the same time. This is very normal in heavy ETL jobs.This can be detected by checking the `distributed_ddl_queue` table and see if there are tasks that are not moving or are stuck for a long time.
 
 If these DDLs completed in some replicas but failed in others, the simplest way to solve this is to execute the failed command in the missed replicas without ON CLUSTER. If most of the DDLs failed then check the number of unfinished records in `distributed_ddl_queue` on the other nodes, because most probably it will be as high as thousands.
 

content/en/altinity-kb-setup-and-maintenance/altinity-kb-data-migration/add_remove_replica.md

@@ -2,12 +2,16 @@
 title: "Add/Remove a new replica to a ClickHouse® cluster"
 linkTitle: "add_remove_replica"
 description: >
-    How to add/remove a new replica manually and using clickhouse-backup
+    How to add/remove a new ClickHouse replica manually and using `clickhouse-backup`
+keywords:
+  - clickhouse replica
+  - clickhouse add replica
+  - clickhouse remove replica
 ---
 
 ## ADD nodes/replicas to a ClickHouse® cluster
 
-To add some replicas to an existing cluster if -30TB then better to use replication:
+To add some ClickHouse® replicas to an existing cluster if -30TB then better to use replication:
 
 - don’t add the `remote_servers.xml` until replication is done.
 - Add these files and restart to limit bandwidth and avoid saturation (70% total bandwidth):
@@ -94,7 +98,7 @@ clickhouse-client --host localhost --port 9000 -mn < schema.sql
 
 ### Using `clickhouse-backup`
 
-- Using `clickhouse-backup` to copy the schema of a replica to another is also convenient and moreover if using Atomic database with `{uuid}` macros in ReplicatedMergeTree engines:
+- Using `clickhouse-backup` to copy the schema of a replica to another is also convenient and moreover if [using Atomic database](/engines/altinity-kb-atomic-database-engine/) with `{uuid}` macros in [ReplicatedMergeTree engines](https://www.youtube.com/watch?v=oHwhXc0re6k):
 
 ```bash
 sudo -u clickhouse clickhouse-backup --schema --rbac create_remote full-replica
@@ -139,7 +143,7 @@ already exists. (REPLICA_ALREADY_EXISTS) (version 23.5.3.24 (official build)). (
 (query: CREATE TABLE IF NOT EXISTS xxxx.yyyy UUID '3c3503c3-ed3c-443b-9cb3-ef41b3aed0a8'
 ```
 
-The DDLs have been executed and some tables have been created and after that dropped but some left overs are left in ZK:
+[The DDLs](/altinity-kb-setup-and-maintenance/altinity-kb-check-replication-ddl-queue/) have been executed and some tables have been created and after that dropped but some left overs are left in ZK:
 - If databases can be dropped then use `DROP DATABASE xxxxx SYNC`
 - If databases cannot be dropped use `SYSTEM DROP REPLICA ‘replica_name’ FROM db.table`
 

content/en/altinity-kb-setup-and-maintenance/altinity-kb-server-config-files.md

@@ -1,11 +1,12 @@
 ---
-title: "Server config files"
+title: "Server configuration files"
 linkTitle: "Server config files"
 description: >
-    How to manage server config files in ClickHouse®
+    How to organize configuration files in ClickHouse® and how to manage changes
 keywords:
   - clickhouse config.xml
   - clickhouse configuration
+weight: 105
 ---
 
 ## Сonfig management (recommended structure)
@@ -16,7 +17,7 @@ By default they are stored in the folder **/etc/clickhouse-server/** in two file
 
 We suggest never change vendor config files and place your changes into separate .xml files in sub-folders. This way is easier to maintain and ease ClickHouse upgrades.
 
-**/etc/clickhouse-server/users.d** – sub-folder for user settings (derived from `users.xml` filename).
+**/etc/clickhouse-server/users.d** – sub-folder for [user settings](/altinity-kb-setup-and-maintenance/rbac/) (derived from `users.xml` filename).
 
 **/etc/clickhouse-server/config.d** – sub-folder for server settings (derived from `config.xml` filename).
 
@@ -84,7 +85,7 @@ cat /etc/clickhouse-server/users.d/memory_usage.xml
 </clickhouse>
 ```
 
-BTW, you can define any macro in your configuration and use them in Zookeeper paths
+BTW, you can define any macro in your configuration and use them in [Zookeeper](https://docs.altinity.com/operationsguide/clickhouse-zookeeper/zookeeper-installation/) paths
 
 ```xml
  ReplicatedMergeTree('/clickhouse/{cluster}/tables/my_table','{replica}')
@@ -182,7 +183,7 @@ The list of user setting which require server restart:
 
 See also `select * from system.settings where description ilike '%start%'`
 
-Also there are several 'long-running' user sessions which are almost never restarted and can keep the setting from the server start (it's DDLWorker, Kafka, and some other service things).
+Also there are several 'long-running' user sessions which are almost never restarted and can keep the setting from the server start (it's DDLWorker, [Kafka](https://altinity.com/blog/kafka-engine-the-story-continues), and some other service things).
 
 ## Dictionaries
 

content/en/altinity-kb-setup-and-maintenance/suspiciously-many-broken-parts.md

@@ -2,10 +2,10 @@
 title: "Suspiciously many broken parts"
 linkTitle: "Suspiciously many broken parts"
 description: >
-    Suspiciously many broken parts error during the server startup.
+    Debugging a common error message
 keywords:
   - clickhouse broken parts
-  - clickhouse too many parts
+  - clickhouse too many broken parts
 ---
 
 ## Symptom:
@@ -28,7 +28,7 @@ Why data could be corrupted?
 
 ## Action:
 
-1. If you are ok to accept the data loss: set up `force_restore_data` flag and clickhouse will move the parts to detached. Data loss is possible if the issue is a result of misconfiguration (i.e. someone accidentally has fixed xml configs with incorrect shard/replica macros, data will be moved to detached folder and can be recovered).
+1. If you are ok to accept the [data loss](/altinity-kb-setup-and-maintenance/recovery-after-complete-data-loss/): set up `force_restore_data` flag and clickhouse will move the parts to detached. Data loss is possible if the issue is a result of misconfiguration (i.e. someone accidentally has fixed xml configs with incorrect [shard/replica macros](https://altinity.com/webinarspage/deep-dive-on-clickhouse-sharding-and-replication), data will be moved to detached folder and can be recovered).
 
     ```bash
     sudo -u clickhouse touch /var/lib/clickhouse/flags/force_restore_data