### Description

Only "search hits" based queries (no aggregations) provide a consistent view on the data when paginating through the result set. With point-in-time, it is possible to support transactional semantics for aggregation queries as well.

This issue is somewhat blocked by https://github.com/elastic/elasticsearch/issues/75528 because a PIT can not immediately be closed if the aggregation result set contains less than `fetch_size` records. This could cause some increased resource utilization due to open PITs. Especially if the client does not close the SQL cursor.
x-pack/plugin/sql/qa/server/src/main/java/org/elasticsearch/xpack/sql/qa/rest/RestSqlTestCase.java
String mode = randomFrom("jdbc", "plain");
        expectBadRequest(() -> runSql(mode, "SELECT * FROM missing"), containsString("1:15: Unknown index [missing]"));
    }
    @Override
    public void testSelectColumnFromMissingIndex() throws Exception {
        String mode = randomFrom("jdbc", "plain");
        expectBadRequest(() -> runSql(mode, "SELECT abc FROM missing"), containsString("1:17: Unknown index [missing]"));
    }
    @Override
    public void testSelectColumnFromEmptyIndex() throws Exception {
        Request request = new Request("PUT", "/test");
        request.setJsonEntity("{}");
        provisioningClient().performRequest(request);
        String mode = randomFrom("jdbc", "plain");
        expectBadRequest(() -> runSql(mode, "SELECT abc FROM " + indexPattern("test")), containsString("1:8: Unknown column [abc]"));
    }
    @Override
    public void testSelectMissingField() throws IOException {
        index("{\"test\":\"test\"}");
        String mode = randomFrom("jdbc", "plain");
        expectBadRequest(() -> runSql(mode, "SELECT foo FROM " + indexPattern("test")), containsString("1:8: Unknown column [foo]"));
    }
    @Override
    public void testSelectMissingFunction() throws Exception {
        index("{\"foo\":1}");
        expectBadRequest(
            () -> runSql(randomMode(), "SELECT missing(foo) FROM " + indexPattern("test")),
            containsString("1:8: Unknown function [missing]")
        );
    }