Skip to content

IGNITE-28981 Document Calcite SELECT FOR UPDATE #13475

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
ignitetcbot wants to merge 2 commits into
base: master
Choose a base branch
from
Open

IGNITE-28981 Document Calcite SELECT FOR UPDATE #13475

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
21a3412
IGNITE-28981 Document Calcite SELECT FOR UPDATE
dspavlov Aug 13, 2026
3fd6578
Merge remote-tracking branch 'origin/master' into IGNITE-28981-docs
dspavlov Aug 13, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
23 changes: 18 additions & 5 deletions docs/_docs/SQL/sql-calcite.adoc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1270,10 +1270,23 @@ So, when `txAwareQueriesEnabled = true` enabled the usage:
====
[discrete]
=== SELECT ... FOR UPDATE
Currently, no locks are held by the UPDATE or SELECT statements.
`SELECT ... FOR UPDATE` statement not supported.
This means lost updates can occur when multiple transactions concurrently modify the same key.
The Calcite-based query engine supports `SELECT ... FOR UPDATE` inside a `PESSIMISTIC` transaction.
The statement acquires row-level locks for the cache entries returned by the query and returns the selected rows.

For example, if you execute a query like `SET salary = salary + 50 WHERE id = 1` concurrently across multiple threads,
note that due to the lost-update anomaly, the final value may not equal the original salary plus 50 multiplied by the number of threads.
[source,sql]
----
SELECT id, salary FROM Person WHERE id = 1 FOR UPDATE;
SELECT p.id FROM Person p JOIN Dept d ON p.deptId = d.id FOR UPDATE OF p.id;
SELECT id FROM Person WHERE id = 1 FOR UPDATE NOWAIT;
SELECT id FROM Person WHERE id = 1 FOR UPDATE WAIT 5;
----

Without `OF`, rows from all cache-based tables participating in the query are locked.
With `OF`, only rows from the tables that own the listed columns are locked.
`NOWAIT` fails immediately if a required lock cannot be acquired.
`WAIT n` waits up to `n` seconds.
If neither option is specified, Ignite uses the transaction timeout.

`SELECT ... FOR UPDATE` is supported only for plain `SELECT` queries over cache-based tables and joins of such tables.
It is not supported for `DISTINCT`, `GROUP BY`, `HAVING`, aggregate-only result sets, system views, or table functions.
====