sync_diff_inspector: AnalyzeValuesFromBuckets did not consider stats_buckets statistics contains null values

[haiying-gao]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

The case where the upper bound of the stats_buckets statistics contains null values ​​has not been considered.

which cause sync_diff_inspector report error

[2026/01/29 00:30:35.728 +08:00] [ERROR] [common.go:607] ["analyze values from buckets"] [column=InfoPublDate] [value=NULL] [error="strconv.ParseUint: parsing \"NULL\": invalid syntax"]        [stack="github.com/pingcap/tidb-tools/pkg/dbutil.AnalyzeValuesFromBuckets\n\t/workspace/source/tidb-tools/pkg/dbutil/common.go:607\ngithub.com/pingcap/tidb-tools/sync_diff_inspector/sp       litter.(*BucketIterator).produceChunks\n\t/workspace/source/tidb-tools/sync_diff_inspector/splitter/bucket.go:304"]

2. What did you expect to see?

sync_diff_inspector running whitout error.

3. What did you see instead?

[2026/01/29 00:30:35.728 +08:00] [ERROR] [common.go:607] ["analyze values from buckets"] [column=InfoPublDate] [value=NULL] [error="strconv.ParseUint: parsing \"NULL\": invalid syntax"]        [stack="github.com/pingcap/tidb-tools/pkg/dbutil.AnalyzeValuesFromBuckets\n\t/workspace/source/tidb-tools/pkg/dbutil/common.go:607\ngithub.com/pingcap/tidb-tools/sync_diff_inspector/sp       litter.(*BucketIterator).produceChunks\n\t/workspace/source/tidb-tools/sync_diff_inspector/splitter/bucket.go:304"]

4. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?

tidb: v7.5.7

5. which tool are you using?

synddiff: v8.5.2-2-g1cf55fb

6. what versionof tool are you using (pump -V or tidb-lightning -V or syncer -V)?

synddiff: v8.5.2-2-g1cf55fb

[ti-chi-bot]

Welcome @haiying-gao! It looks like this is your first issue to pingcap/tidb-tools 🎉