Fix optimize read in order from a view.

[vitlibar]

Changelog category:

• Performance Improvement

Changelog entry:

Enable ORDER BY optimization for reading data in corresponding order from a MergeTree table in case that the table is behind a view.

For example, the following SELECT

CREATE TABLE table1 (x UInt64) ENGINE=MergeTree ORDER BY x;
CREATE VIEW view1 AS SELECT x FROM table1;
...
SELECT * FROM (SELECT * FROM view1) ORDER BY x DESC LIMIT 20;

must understand that the table is already ordered and read only a few rows from the table (before this PR this query used to read the full table).

[robot-ch-test-poll]

This is an automated comment for commit b1bddae with description of existing statuses. It's updated for the latest CI running

❌ Click here to open a full report in a separate page

Successful checks

Check name	Description	Status
AST fuzzer	Runs randomly generated queries to catch program errors. The build type is optionally given in parenthesis. If it fails, ask a maintainer for help	✅ success
CI running	A meta-check that indicates the running CI. Normally, it's in success or pending state. The failed status indicates some problems with the PR	✅ success
ClickHouse build check	Builds ClickHouse in various configurations for use in further steps. You have to fix the builds that fail. Build logs often has enough information to fix the error, but you might have to reproduce the failure locally. The cmake options can be found in the build log, grepping for cmake. Use these options and follow the general build process	✅ success
Compatibility check	Checks that clickhouse binary runs on distributions with old libc versions. If it fails, ask a maintainer for help	✅ success
Docker image for servers	The check to build and optionally push the mentioned image to docker hub	✅ success
Fast test	Normally this is the first check that is ran for a PR. It builds ClickHouse and runs most of stateless functional tests, omitting some. If it fails, further checks are not started until it is fixed. Look at the report to see which tests fail, then reproduce the failure locally as described here	✅ success
Flaky tests	Checks if new added or modified tests are flaky by running them repeatedly, in parallel, with more randomization. Functional tests are run 100 times with address sanitizer, and additional randomization of thread scheduling. Integrational tests are run up to 10 times. If at least once a new test has failed, or was too long, this check will be red. We don't allow flaky tests, read the doc	✅ success
Install packages	Checks that the built packages are installable in a clear environment	✅ success
Integration tests	The integration tests report. In parenthesis the package type is given, and in square brackets are the optional part/total tests	✅ success
Mergeable Check	Checks if all other necessary checks are successful	✅ success
Performance Comparison	Measure changes in query performance. The performance test report is described in detail here. In square brackets are the optional part/total tests	✅ success
Push to Dockerhub	The check for building and pushing the CI related docker images to docker hub	✅ success
SQLTest	There's no description for the check yet, please add it to tests/ci/ci_config.py:CHECK_DESCRIPTIONS	✅ success
SQLancer	Fuzzing tests that detect logical bugs with SQLancer tool	✅ success
Sqllogic	Run clickhouse on the sqllogic test set against sqlite and checks that all statements are passed	✅ success
Stateful tests	Runs stateful functional tests for ClickHouse binaries built in various configurations -- release, debug, with sanitizers, etc	✅ success
Stateless tests	Runs stateless functional tests for ClickHouse binaries built in various configurations -- release, debug, with sanitizers, etc	✅ success
Style Check	Runs a set of checks to keep the code style clean. If some of tests failed, see the related log from the report	✅ success
Unit tests	Runs the unit tests for different release types	✅ success
Upgrade check	Runs stress tests on server version from last release and then tries to upgrade it to the version from the PR. It checks if the new server can successfully startup without any errors, crashes or sanitizer asserts	✅ success

Check name	Description	Status
Stress test	Runs stateless functional tests concurrently from several clients to detect concurrency-related errors	❌ failure

[vitlibar]

StorageView implicitly applies the materialize() function to each column of the result of an internal query (see StorageView::read). And then optimize_read_in_order checks the monotonicity of applied functions (see matchTrees()). So if materialize() becomes monotonic then the optimization optimize_read_in_order can work for views.

[vitlibar]

Also EXPLAIN shows the change this PR makes (notice the ReadType):

Before:

> EXPLAIN actions=1 SELECT * FROM (SELECT * FROM view1) ORDER BY x DESC LIMIT 20;

┌─explain─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ Expression (Projection)                                                                                                                                                                                         │
│ Actions: INPUT :: 0 -> x UInt64 : 0                                                                                                                                                                             │
│ Positions: 0                                                                                                                                                                                                    │
│   Limit (preliminary LIMIT (without OFFSET))                                                                                                                                                                    │
│   Limit 20                                                                                                                                                                                                      │
│   Offset 0                                                                                                                                                                                                      │
│     Sorting (Sorting for ORDER BY)                                                                                                                                                                              │
│     Sort description: x DESC                                                                                                                                                                                    │
│     Limit 20                                                                                                                                                                                                    │
│       Expression ((Before ORDER BY + (Projection + (Before ORDER BY + (Convert VIEW subquery result to VIEW table structure + (Materialize constants after VIEW subquery + (Projection + Before ORDER BY))))))) │
│       Actions: INPUT : 0 -> x UInt64 : 0                                                                                                                                                                        │
│                FUNCTION materialize(x :: 0) -> materialize(x) UInt64 : 1                                                                                                                                        │
│                ALIAS materialize(x) :: 1 -> x UInt64 : 0                                                                                                                                                        │
│       Positions: 0                                                                                                                                                                                              │
│         ReadFromMergeTree (default.table1)                                                                                                                                                                      │
│         ReadType: Default                                                                                                                                                                                       │
│         Parts: 1                                                                                                                                                                                                │
│         Granules: 1                                                                                                                                                                                             │
└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘

After:

> EXPLAIN actions=1 SELECT * FROM (SELECT * FROM view1) ORDER BY x DESC LIMIT 20;

┌─explain─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ Expression (Projection)                                                                                                                                                                                         │
│ Actions: INPUT :: 0 -> x UInt64 : 0                                                                                                                                                                             │
│ Positions: 0                                                                                                                                                                                                    │
│   Limit (preliminary LIMIT (without OFFSET))                                                                                                                                                                    │
│   Limit 20                                                                                                                                                                                                      │
│   Offset 0                                                                                                                                                                                                      │
│     Sorting (Sorting for ORDER BY)                                                                                                                                                                              │
│     Prefix sort description: x DESC                                                                                                                                                                             │
│     Result sort description: x DESC                                                                                                                                                                             │
│     Limit 20                                                                                                                                                                                                    │
│       Expression ((Before ORDER BY + (Projection + (Before ORDER BY + (Convert VIEW subquery result to VIEW table structure + (Materialize constants after VIEW subquery + (Projection + Before ORDER BY))))))) │
│       Actions: INPUT : 0 -> x UInt64 : 0                                                                                                                                                                        │
│                FUNCTION materialize(x :: 0) -> materialize(x) UInt64 : 1                                                                                                                                        │
│                ALIAS materialize(x) :: 1 -> x UInt64 : 0                                                                                                                                                        │
│       Positions: 0                                                                                                                                                                                              │
│         ReadFromMergeTree (default.table1)                                                                                                                                                                      │
│         ReadType: InReverseOrder                                                                                                                                                                                │
│         Parts: 1                                                                                                                                                                                                │
│         Granules: 1                                                                                                                                                                                             │
└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘

[SaltTan]

related #34720
maybe also #18561?

[nickitat]

imo it is better to check the query plan

[vitlibar]

Ok, I've rewritten the test.

[vitlibar]

related #34720 maybe also #18561?

#34720 - yes
#18561 - no