TiFlash Synchronization Delay Issue

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

Original topic: tiflash同步延迟问题

| username: Ming

Hello everyone, I would like to determine the synchronization delay of incremental data from TiKV to TiFlash. What method can I use to observe this?

| username: tidb菜鸟一只 | Original post link

The general latency is very low, at the millisecond level, and queries on TiFlash can also achieve consistent queries. What requirements are you based on to obtain this?

| username: Ming | Original post link

TiFlash can achieve consistent queries, but there may be a delay that causes the query to time out and return an error because it hasn’t synchronized yet. I’ve encountered situations where it returns an error. Basically, there are two outcomes: either it retrieves the data, or it returns an error. I just want to test this delay.

| username: WalterWj | Original post link

| username: Ming | Original post link

When inserting data with existing replicas, will the latency from TiKV to TiFlash cause any changes in PROGRESS?

| username: Ming | Original post link

Or, is there any difference in handling between the synchronization of building a replica and the synchronization in the existing process, one being full and the other incremental? If there is no difference, should we just calculate the building of the replica?

| username: WalterWj | Original post link

If you can’t catch up, it will change.

| username: Ming | Original post link

Is there a time range for this definition that it can’t catch up with? Are there any related parameters to control it?

| username: WalterWj | Original post link

It should be the percentage difference, right? It should be unrelated to time.

| username: Ming | Original post link

Okay, thank you.