sql: DELETE always reports actual row count: 1 in EXPLAIN ANALYZE

[yuzefovich]

I think regardless of how many rows are deleted by the DELETE stmt, we seem to always say actual row count: 1 in EXPLAIN ANALYZE. A couple of examples:

-- empty table
CREATE TABLE t (k INT PRIMARY KEY);
EXPLAIN ANALYZE DELETE FROM t WHERE k = 1 OR k = 2;
EXPLAIN ANALYZE DELETE FROM t WHERE k > 100;

-- empty table
CREATE TABLE t (k INT PRIMARY KEY, v INT);
EXPLAIN ANALYZE DELETE FROM t WHERE v % 2 = 0;

-- some rows are deleted
CREATE TABLE t (k INT PRIMARY KEY);
INSERT INTO t SELECT generate_series(1, 1000);
EXPLAIN ANALYZE DELETE FROM t WHERE k = 1 OR k = 2;
EXPLAIN ANALYZE DELETE FROM t WHERE k > 100;

CREATE TABLE t (k INT PRIMARY KEY, v INT);
INSERT INTO t SELECT i, i FROM generate_series(1, 1000) AS g(i);
EXPLAIN ANALYZE DELETE FROM t WHERE v % 2 = 0;

Jira issue: CRDB-46443

[blathers-crl]

Based on the specified backports for linked PR #139278, I applied the following new label(s) to this issue: branch-release-25.1. Please adjust the labels as needed to match the branches actually affected by this issue, including adding any known older branches.

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