[TD-2081]<hotfix>: fix alter blocks problem

taosAcquireRef return a pointer, not an integer

Feature/wal

[TD-2078]<fix> read double data error

[TD-1986]<fix>: default days to 10 instead of 2

TD-1982

Merge pull request #4212 from taosdata/dependabot/maven/tests/examples/JDBC/connectionPools/com.mchange-c3p0-0.9.5.4

Bump c3p0 from 0.9.5.2 to 0.9.5.4 in /tests/examples/JDBC/connectionPools

[update]

Bumps [c3p0](https://github.com/swaldman/c3p0) from 0.9.5.2 to 0.9.5.4.
- [Release notes](https://github.com/swaldman/c3p0/releases)
- [Commits](https://github.com/swaldman/c3p0/compare/c3p0-0.9.5.2...c3p0-0.9.5.4)
Signed-off-by: Ndependabot[bot] <support@github.com>

[TD-2084]<hotfix>: invalid read when close TSDB

Feature/td 2052

Update TAOS SQL-ch.md