close#26882
We should not use the singleNodePlan to generate the rootPlanFragment if the query is inside a insert statement or distributedPlanner will be null.
introduced in #15491
Concurrent schema change and txn may cause dead lock. An example:
Txn T commit but not publish;
Run schema change or rollup on T's related partition, add alter replica R;
sc/rollup add a sched txn watermark M;
Restart fe;
After fe restart, T's loadedTblIndexes will clear because it's not save to disk;
T will publish version to all tablet, including sc/rollup's new alter replica R;
Since R not contains txn data, so the T will fail. It will then always waitting for R's data;
sc/rollup wait for txn before M to finish, only after that it will let R copy history data;
Since T's not finished, so sc/rollup will always wait, so R will nerver copy history data;
Txn T and sc/rollup will wait each other forever, cause dead lock;
Fix: because sc/rollup will ensure double write after the sched watermark M, so for finish transaction, when checking a alter replica:
if txn id is bigger than M, check it just like a normal replica;
otherwise skip check this replica, the BE will modify history data later.
Improve the accuracy of sample stats collection. For non distribution columns, use
`n*d / (n - f1 + f1*n/N)`
where `f1` is the number of distinct values that occurred exactly once in our sample of n rows (from a total of N),
and `d` is the total number of distinct values in the sample.
For distribution columns, use `ndv(n) * fraction of tablets sampled` for NDV.
For very large tablet to sample, use limit to control the total lines to scan (for non key column only, because key column is sorted and will be inaccurate using limit).
This commit overhauls the JDBC connector logic within our project, transitioning from the previous mechanism of fetching data through JNI calls for individual ResultSet items to a more efficient and unified approach using the VectorTable data structure.
sql select * from t1 a join t1 b on b.id in (select 1) and a.id = b.id; will report an error.
This pr support uncorrelated subquery in join condition to fix it
When doing LoadPendingTask or LoadLoadingTask, there may be some Error thrown,
such as `NoClassDefFoundError`, but previously, we only catch java's `Exception`, so
other kind of error can not be shown clearly.
Now the update time of hms table is generated by every FE node (Use `System.currentTimestamp()` separately), so the update time of a hms table may be different between FE nodes, always the same query can not hit the sql-cache if we submit it more than one times through different FE nodes. This pr mainly do following changes to avoid this problem.
- Use the `transient_lastDdlTime` instead of `System.currentTimestamp` as the `schemaUpdateTime` of hms tables
- Use the `eventTime` in hms event instead of `System.currentTimestamp` as the update time when processing hms events
The local meta/info files generated during backup are not distinguished
by repo names. If two backup jobs with the same name are submitted to
different repos at the same time, meta/info may be overwritten by another
backup job.
