hi. i m confused about data flow in influxDB.
- influxDB don’t use memory when read data?
document say about engine works. (InfluxDB storage engine | InfluxDB OSS 2.1 Documentation)
- The write request is appended to the end of the WAL file.
- Data is written to disk using fsync().
- The in-memory cache is updated.
- When data is successfully written to disk, a response confirms the write request was successful.
but other document says.
“After fields are stored safely in TSM files, the WAL is truncated and the cache is cleared.”
As far as I understand, when i send write request, data saved in disk and then removed in memory.
- Where is Shard’s data located?
As mentioned above, data is stored on disk when processed, and some blogs say that Shard Groups is stored in memory and on disk after Shard Groups Duration.
what is right?