*: support specifying range bits for auto_random

[tangenta]

What problem does this PR solve?

Issue Number: close https://github.com/pingcap/tidb/issues/32508

Problem Summary: Previously, auto_random column makes use of the highest several bits for shard. An auto_random ID can be too large to be represented in some special data types. For example, JSON's number can only represent 54-bits integer.

What is changed and how it works?

This PR introduces a new syntax, which allows users to specify the max "range bits" for the BIGINT type:

CREATE TABLE t (a BIGINT AUTO_RANDOM(5,54) PRIMARY KEY, b INT);  -- the generated ID is guaranteed to be smaller than (2^53)-1
CREATE TABLE t (a BIGINT UNSIGNED AUTO_RANDOM(5,32) PRIMARY KEY, b INT);  -- a workaround for "INT UNSIGNED AUTO_RANDOM(5)"

In the above SQLs, 54 and 32 are the "range bits". The new 64-bit shard ID format is as follows:

[sign bit] + [reserved bits] + [shard bits] + [incremental bits]

• The range bits is equal to sign bit + shard bits + incremental bits.
• The reserved bits is equal to 64 - range bits. The content of the reserved bits are always zero.

Check List

Tests

• [ ] Unit test
• [x] Integration test
• [ ] Manual test (add detailed scripts or steps below)
• [ ] No code

Side effects

• [ ] Performance regression: Consumes more CPU
• [ ] Performance regression: Consumes more Memory
• [ ] Breaking backward compatibility

Documentation

• [ ] Affects user behaviors
• [x] Contains syntax changes
• [ ] Contains variable changes
• [ ] Contains experimental features
• [ ] Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• Defined2014
• bb7133

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[sre-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/bf44ec094c930a6d0d1c026e81898751064b98a7

[bb7133]

@tangenta Please resolve the conflicts.

[tangenta]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 5fa589ab225646072774d45d51ea2cd19bed86ef

[sre-bot]

TiDB MergeCI notify

✅ Well Done! New fixed [1] after this pr merged.

CI Name	Result	Duration	Compare with Parent commit
idc-jenkins-ci-tidb/integration-ddl-test	✅ all 6 tests passed	6 min 44 sec	Fixed
idc-jenkins-ci/integration-cdc-test	🟢 all 36 tests passed	34 min	Existing passed
idc-jenkins-ci-tidb/integration-common-test	🟢 all 17 tests passed	13 min	Existing passed
idc-jenkins-ci-tidb/common-test	🟢 all 11 tests passed	12 min	Existing passed
idc-jenkins-ci-tidb/tics-test	🟢 all 1 tests passed	10 min	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-2	🟢 all 28 tests passed	4 min 56 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-1	🟢 all 26 tests passed	4 min 34 sec	Existing passed
idc-jenkins-ci-tidb/mybatis-test	🟢 all 1 tests passed	3 min 14 sec	Existing passed
idc-jenkins-ci-tidb/integration-compatibility-test	🟢 all 1 tests passed	3 min 4 sec	Existing passed
idc-jenkins-ci-tidb/plugin-test	🟢 build success, plugin test success	4min	Existing passed