database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-29 10:41:53 +03:00
Code Activity

Error out if SKIP LOCKED and WITH TIES are both specified

Browse Source 
Both bugs #16676[1] and #17141[2] illustrate that the combination of
SKIP LOCKED and FETCH FIRST WITH TIES break expectations when it comes
to rows returned to other sessions accessing the same row.  Since this
situation is detectable from the syntax and hard to fix otherwise,
forbid for now, with the potential to fix in the future.

[1] https://postgr.es/m/16676-fd62c3c835880da6@postgresql.org
[2] https://postgr.es/m/17141-913d78b9675aac8e@postgresql.org

Backpatch-through: 13, where WITH TIES was introduced
Author: David Christensen <david.christensen@crunchydata.com>
Discussion: https://postgr.es/m/CAOxo6XLPccCKru3xPMaYDpa+AXyPeWFs+SskrrL+HKwDjJnLhg@mail.gmail.com
This commit is contained in:
Alvaro Herrera
2021-10-01 18:29:18 -03:00
parent 7adbe186f7
commit 170206e458
5 changed files with 29 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
src/backend/parser/gram.y
View File

@ -16163,6 +16163,21 @@ insertSelectOptions(SelectStmt *stmt,
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("WITH TIES cannot be specified without ORDER BY clause")));
if (limitClause->limitOption == LIMIT_OPTION_WITH_TIES && stmt->lockingClause)
{
ListCell *lc;
foreach(lc, stmt->lockingClause)
{
LockingClause *lock = lfirst_node(LockingClause, lc);
if (lock->waitPolicy == LockWaitSkip)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("%s and %s options cannot be used together",
"SKIP LOCKED", "WITH TIES")));
}
}
stmt->limitOption = limitClause->limitOption;
}
if (withClause)