planner/core: support partition pruning for partition expression floor(unix_timestamp()) (#16402)

[sre-bot]

cherry-pick #16402 to release-3.1

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What problem does this PR solve?

Issue Number: close #16354

Problem Summary:

Support partition pruning for floor(unix_timestamp()

create table t (ts timestamp(3)) partition by range (floor(unix_timestamp(ts))) (
...)

What is changed and how it works?

What's Changed:

Take function floor(unix_timestamp()) as monotoneIncFuncs, special handle for this case.

How it Works:

If the partition function is monotoneous, i.e.

for all x > y => f(x) > f(y)

That partition function can be used by the partition pruning algorithm.

If we view floor(unix_timestamp()) as a single function, it basicly conform to the definition.

for all x > y => f(x) >= f(y)

Related changes

• PR to update pingcap/docs/pingcap/docs-cn:
• PR to update pingcap/tidb-ansible:
• Need to cherry-pick to the release branch

Check List

Tests

• Unit test
• Integration test

Release note

[sre-bot]

/run-all-tests

[sre-bot]

@lysu, @jackysp, @eurekaka, @XuHuaiyu, @imtbkcat, PTAL.

[tiancaiamao]

/run-all-tests

[tiancaiamao]

PTAL @imtbkcat @jackysp

[imtbkcat]

LGTM

[jackysp]

LGTM