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*: refine TiDB product basic FAQs descriptions #10575

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*: refine TiDB product basic FAQs descriptions
TomShawn Sep 28, 2022
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Update capitalization
lilin90 Oct 7, 2022
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16 changes: 9 additions & 7 deletions faq/tidb-faq.md
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Expand Up @@ -14,11 +14,11 @@ This document lists the Most Frequently Asked Questions about TiDB.

### What is TiDB?

TiDB is a distributed SQL database that features in horizontal scalability, high availability and consistent distributed transactions. It also enables you to use MySQL's SQL syntax and protocol to manage and retrieve data.
[TiDB](https://github.com/pingcap/tidb) is an open-source NewSQL database that supports Hybrid Transactional and Analytical Processing (HTAP) workloads. It is MySQL compatible and features horizontal scalability, strong consistency, and high availability. The goal of TiDB is to provide users with a one-stop database solution that covers OLTP (Online Transactional Processing), OLAP (Online Analytical Processing), and HTAP services. TiDB is suitable for various use cases that require high availability and strong consistency with large-scale data.

### What is TiDB's architecture?

The TiDB cluster has three components: the TiDB server, the PD (Placement Driver) server, and the TiKV server. For more details, see [TiDB architecture](/tidb-architecture.md).
The TiDB cluster has three components: the TiDB server, the PD (Placement Driver) server, and the TiKV server. For more details, see [TiDB architecture](/tidb-architecture.md), [TiDB storage](/tidb-storage.md), [TiDB computing](/tidb-computing.md), and [TiDB scheduling](/tidb-scheduling.md).

### Is TiDB based on MySQL?

Expand Down Expand Up @@ -77,7 +77,9 @@ Usage of ./bin/tidb-server:

### In addition to the TiDB documentation, are there any other ways to acquire TiDB knowledge?

Currently [TiDB documentation](/overview.md#tidb-introduction) is the most important and timely way to get TiDB related knowledge. In addition, we also have some technical communication groups. If you have any needs, contact [info@pingcap.com](mailto:info@pingcap.com).
- [TiDB documentation](https://docs.pingcap.com/): the most important and timely way to get TiDB related knowledge.
- [TiDB blogs](https://www.pingcap.com/blog/): learn technical articles, product insights, and case studies.
- [PingCAP Education](https://www.pingcap.com/education/?from=en): take online courses and certification programs.

### What is the length limit for the TiDB user name?

Expand All @@ -96,7 +98,7 @@ No. The JDBC driver of TiDB is MySQL JDBC (Connector/J). When using Atomikos, se

After you configure the two data sources of Atomikos, set the JDBC drives to XA. When Atomikos operates TM and RM (DB), Atomikos sends the command including XA to the JDBC layer. Taking MySQL for an example, when XA is enabled in the JDBC layer, JDBC will send a series of XA logic operations to InnoDB, including using DML to change the `redo` log. This is the operation of the two-phase commit. The current TiDB version does not support the upper application layer JTA/XA and does not parse XA operations sent by Atomikos.

As a standalone database, MySQL can only implement across-database transactions using XA; while TiDB supports distributed transactions using Google Percolator transaction model and its performance stability is higher than XA, so TiDB does not support XA and there is no need for TiDB to support XA.
As a standalone database, MySQL can only implement across-database transactions using XA; while TiDB supports distributed transactions using Google Percolator transaction model and its performance stability is higher than XA, so TiDB does not support JTA/XA and there is no need for TiDB to support XA.

### How could TiDB support high concurrent `INSERT` or `UPDATE` operations to the columnar storage engine (TiFlash) without hurting performance?

Expand All @@ -111,12 +113,12 @@ Yes. TiFlash maintains strong data consistency by default.

### TiKV for data storage

See [TiDB Internal (I) - Data Storage](https://en.pingcap.com/blog/tidb-internal-data-storage/).
See [TiDB Internal (I) - Data Storage](https://www.pingcap.com/blog/tidb-internal-data-storage/?from=en).

### TiDB for data computing

See [TiDB Internal (II) - Computing](https://en.pingcap.com/blog/tidb-internal-computing/).
See [TiDB Internal (II) - Computing](https://www.pingcap.com/blog/tidb-internal-computing/?from=en).

### PD for scheduling

See [TiDB Internal (III) - Scheduling](https://en.pingcap.com/blog/tidb-internal-scheduling/).
See [TiDB Internal (III) - Scheduling](https://www.pingcap.com/blog/tidb-internal-scheduling/?from=en).
8 changes: 4 additions & 4 deletions tidb-architecture.md
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Expand Up @@ -25,17 +25,17 @@ As a distributed database, TiDB is designed to consist of multiple components. T

## TiDB server

The TiDB server is a stateless SQL layer that exposes the connection endpoint of the MySQL protocol to the outside. The TiDB server receives SQL requests, performs SQL parsing and optimization, and ultimately generates a distributed execution plan. It is horizontally scalable and provides the unified interface to the outside through the load balancing components such as Linux Virtual Server (LVS), HAProxy, or F5. It does not store data and is only for computing and SQL analyzing, transmitting actual data read request to TiKV nodes (or TiFlash nodes).
The [TiDB server](/tidb-computing.md) is a stateless SQL layer that exposes the connection endpoint of the MySQL protocol to the outside. The TiDB server receives SQL requests, performs SQL parsing and optimization, and ultimately generates a distributed execution plan. It is horizontally scalable and provides the unified interface to the outside through the load balancing components such as Linux Virtual Server (LVS), HAProxy, or F5. It does not store data and is only for computing and SQL analyzing, transmitting actual data read request to TiKV nodes (or TiFlash nodes).

## Placement Driver (PD) server

The PD server is the metadata managing component of the entire cluster. It stores metadata of real-time data distribution of every single TiKV node and the topology structure of the entire TiDB cluster, provides the TiDB Dashboard management UI, and allocates transaction IDs to distributed transactions. The PD server is "the brain" of the entire TiDB cluster because it not only stores metadata of the cluster, but also sends data scheduling command to specific TiKV nodes according to the data distribution state reported by TiKV nodes in real time. In addition, the PD server consists of three nodes at least and has high availability. It is recommended to deploy an odd number of PD nodes.
The [PD server](/tidb-scheduling.md) is the metadata managing component of the entire cluster. It stores metadata of real-time data distribution of every single TiKV node and the topology structure of the entire TiDB cluster, provides the TiDB Dashboard management UI, and allocates transaction IDs to distributed transactions. The PD server is "the brain" of the entire TiDB cluster because it not only stores metadata of the cluster, but also sends data scheduling command to specific TiKV nodes according to the data distribution state reported by TiKV nodes in real time. In addition, the PD server consists of three nodes at least and has high availability. It is recommended to deploy an odd number of PD nodes.

## Storage servers

### TiKV server

The TiKV server is responsible for storing data. TiKV is a distributed transactional key-value storage engine.
The [TiKV server](/tidb-storage.md) is responsible for storing data. TiKV is a distributed transactional key-value storage engine.

<CustomContent platform="tidb">

Expand All @@ -53,4 +53,4 @@ Multiple Regions exist in each TiKV node. TiKV APIs provide native support to di

### TiFlash server

The TiFlash Server is a special type of storage server. Unlike ordinary TiKV nodes, TiFlash stores data by column, mainly designed to accelerate analytical processing.
The [TiFlash Server](/tiflash/tiflash-overview.md) is a special type of storage server. Unlike ordinary TiKV nodes, TiFlash stores data by column, mainly designed to accelerate analytical processing.
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2 changes: 1 addition & 1 deletion user-account-management.md
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Expand Up @@ -12,7 +12,7 @@ This document describes how to manage a TiDB user account.

TiDB stores the user accounts in the table of the `mysql.user` system database. Each account is identified by a user name and the client host. Each account may have a password.

You can connect to the TiDB server using the MySQL client, and use the specified account and password to login:
You can connect to the TiDB server using the MySQL client, and use the specified account and password to login. For each user name, make sure that it contains no more than 32 characters.

```sql
shell> mysql --port 4000 --user xxx --password
Expand Down