Does raftdb have a memtable?

Note:
This topic has been translated from a Chinese forum by GPT and might contain errors.

Original topic: raftdb是否有 memtable

| username: 考试没答案

[TiDB Usage Environment] Production Environment / Testing / PoC
[TiDB Version]
[Reproduction Path] What operations were performed when the issue occurred
[Encountered Issue: Problem Phenomenon and Impact] Question: Does raftdb have a memtable?
[Resource Configuration] Go to TiDB Dashboard - Cluster Info - Hosts and take a screenshot of this page
[Attachments: Screenshots/Logs/Monitoring]

| username: 考试没答案 | Original post link

I saw the official documentation:


Can any teacher help answer this?

| username: zhanggame1 | Original post link

RaftDB is no longer used; the new version now uses Raft Engine. It is a built-in persistent storage engine with a log-structured design, providing multi-Raft log storage for TiKV. Starting from v5.4, TiDB supports using Raft Engine as the log storage engine for TiKV.

For more information, refer to the following documents:

| username: 考试没答案 | Original post link

Still using it? The documentation I’m looking at is the latest.

| username: WinterLiu | Original post link

It uses RocksDB, one for storing data and one for storing Raft logs.

| username: zhanggame1 | Original post link

The documentation here hasn’t been updated.
Install version 7.5 and check the directory name on the server to find out.

| username: TIDB-Learner | Original post link

The questions and answers both confuse me. I still need to study hard; some concepts are ambiguous.

| username: 考试没答案 | Original post link

I’ll try upgrading my TiDB. Thank you!

| username: redgame | Original post link

That version, if I remember correctly, also didn’t have it.

| username: TiDBer_aaO4sU46 | Original post link

No…

| username: 考试没答案 | Original post link

How should this be explained???

| username: forever | Original post link

Both are placed in RocksDB, and RocksDB itself requires a memtable.

| username: zhaokede | Original post link

I haven’t used version 7 yet, and I can’t see it.

| username: 考试没答案 | Original post link

Okay. Thank you!

| username: zhanggame1 | Original post link

Each of RaftDB and data has its own RocksDB instance.
The RocksDB instance for RaftDB has one column family (cf), while the instance for data has three column families (cf).

| username: 考试没答案 | Original post link

Sorry, I can’t translate the content from the image. Please provide the text you need translated.

| username: zhanggame1 | Original post link

Yes, I made a mistake here.

| username: dba远航 | Original post link

RocksDB itself requires a memtable.

| username: system | Original post link

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