Are there any limitations on TIDB join operations?

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

Original topic: TIDB join 操作有什么限制吗

| username: 小于同学

Are there any limitations on TIDB join operations?

| username: forever | Original post link

Just ask about the join.

| username: 啦啦啦啦啦 | Original post link

Please share the problematic SQL.

| username: zhanggame1 | Original post link

The main data volume is large, which can cause OOM (Out of Memory).

| username: TiDBer_RjzUpGDL | Original post link

Poor performance of large table joins

| username: residentevil | Original post link

You can check whether INDEXJOIN or HASHJOIN is used in the SQL execution plan, as there is a performance difference.

| username: DBAER | Original post link

Pay attention to OOM.

| username: 哈喽沃德 | Original post link

As long as the memory is large enough, there shouldn’t be any issues.

| username: FutureDB | Original post link

Join operations, especially HashJoin, consume a significant amount of memory. If disk spilling is not configured, it is quite easy to encounter OOM (Out of Memory) issues. Additionally, the order of join associations is very important. Sometimes, one of the reasons for slow multi-table joins is that the execution plan deviates, causing issues with the association order.

| username: Kongdom | Original post link

The performance of inner join is far superior to that of left join.

| username: kelvin | Original post link

You can take some of the data out to create a table, reducing the number of Join statements. I feel this will be much faster.

| username: TiDBer_5cwU0ltE | Original post link

What kind of effect do you want? You need to analyze specific problems specifically. Speaking in general terms doesn’t seem to be of much use.

| username: system | Original post link

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