feat: support set timezone in db

[Taylor-lagrange]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

support set timezone in db

Please explain IN DETAIL what the changes are in this PR and why they are needed:

• Add default_time_zone as a option in standalone / frontend, enable user config system time zone, default system time zone is UTC
• Attach system time zone in QueryContext, when a new session build, the system time zone will be default user time zone, user can change time zone by SET time_zone = 'UTC';

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.

Refer to a related PR or issue link (optional)

#2907
#2893

[codecov]

Codecov Report

Attention: 11 lines in your changes are missing coverage. Please review.

Comparison is base (06fd7fd) 85.87% compared to head (22d7413) 85.19%.
Report is 7 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2992      +/-   ##
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- Coverage    85.87%   85.19%   -0.68%     
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  Files          780      783       +3     
  Lines       126184   126656     +472     
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- Hits        108356   107909     -447     
- Misses       17828    18747     +919     

[killme2008]

I think timezone is better than time_zone. And it's a standard term. So can we rename all these funcitons, variables from time_zone to timezone?

[waynexia]

LGTM.

Maybe also add some cases use time zone other than GMT and Shanghai?

[Taylor-lagrange]

I think timezone is better than time_zone. And it's a standard term. So can we rename all these funcitons, variables from time_zone to timezone?

time_zone mainly from SQL SET time_zone = xxxx; time_ zone or timezone both seems fine. I'll change it

[killme2008]

I think timezone is better than time_zone. And it's a standard term. So can we rename all these funcitons, variables from time_zone to timezone?

time_zone mainly from SQL SET time_zone = xxxx; time_ zone or timezone both seems fine. I'll change it

In Chrono API, it use timezone https://docs.rs/chrono/latest/chrono/struct.DateTime.html#method.with_timezone

[Taylor-lagrange]

But most of word used in our codebase is time_zone, even the main time zone related struct TimeZone in src/common/time/src/timezone.rs is call TimeZone, we should change it all?

[killme2008]

But most of word used in our codebase is time_zone, even the main time zone related struct TimeZone in src/common/time/src/timezone.rs is call TimeZone, we should change it all?

Yes, let's do a refactor. It looks like not so much!

tests-integration/tests/sql.rs
221:    let _ = conn.execute("SET time_zone = 'UTC'").await.unwrap();
222:    let time_zone = conn.fetch_all("SELECT @@time_zone").await.unwrap();
223:    assert_eq!(time_zone[0].get::<String, usize>(0), "UTC");
242:    let _ = conn.execute("SET time_zone = '+08:00'").await.unwrap();

src/common/time/src/timezone.rs
90:pub fn system_time_zone_name() -> String {

src/common/time/src/timestamp.rs
1057:    fn test_parse_in_time_zone() {

src/servers/src/mysql/writer.rs
197:                        .write_col(v.to_chrono_datetime_with_timezone(query_context.time_zone()))?,
199:                        .write_col(v.to_chrono_datetime_with_timezone(query_context.time_zone()))?,
211:                        .write_col(v.to_timezone_aware_string(query_context.time_zone()))?,

src/servers/src/mysql/federated.rs
24:use common_time::timezone::system_time_zone_name;
59:static SET_TIME_ZONE_PATTERN: Lazy<Regex> =
60:    Lazy::new(|| Regex::new(r"(?i)^SET TIME_ZONE\s*=\s*'(\S+)'").unwrap());
203:            "time_zone" => query_context
204:                .time_zone()
207:            "system_time_zone" => system_time_zone_name(),
271:    if let Some(captures) = SET_TIME_ZONE_PATTERN.captures(query) {
275:            session.set_time_zone(timezone);
396:        let query = "/* mysql-connector-java-8.0.17 (Revision: 16a712ddb3f826a1933ab42b0039f7fb9eebc6ec) */SELECT  @@session.auto_increment_increment AS auto_increment_increment, @@character_set_client AS character_set_client, @@character_set_connection AS character_set_connection, @@character_set_results AS character_set_results, @@character_set_server AS character_set_server, @@collation_server AS collation_server, @@collation_connection AS collation_connection, @@init_connect AS init_connect, @@interactive_timeout AS interactive_timeout, @@license AS license, @@lower_case_table_names AS lower_case_table_names, @@max_allowed_packet AS max_allowed_packet, @@net_write_timeout AS net_write_timeout, @@performance_schema AS performance_schema, @@sql_mode AS sql_mode, @@system_time_zone AS system_time_zone, @@time_zone AS time_zone, @@transaction_isolation AS transaction_isolation, @@wait_timeout AS wait_timeout;";
399:| auto_increment_increment | character_set_client | character_set_connection | character_set_results | character_set_server | collation_server | collation_connection | init_connect | interactive_timeout | license | lower_case_table_names | max_allowed_packet | net_write_timeout | performance_schema | sql_mode | system_time_zone | time_zone | transaction_isolation | wait_timeout; |
440:    fn test_set_time_zone() {
443:            "set time_zone = 'UTC'",
454:        assert_eq!("UTC", query_context.time_zone().unwrap().to_string());
456:        let output = check("select @@time_zone", query_context.clone(), session.clone());
461:| @@time_zone |

src/session/src/context.rs
38:    time_zone: Option<TimeZone>,
60:            time_zone: Default::default(),
118:    pub fn time_zone(&self) -> Option<TimeZone> {
119:        self.time_zone.clone()
145:            time_zone: self.time_zone.unwrap_or(None),

src/session/src/lib.rs
36:    time_zone: ArcSwap<Option<TimeZone>>,
48:            time_zone: ArcSwap::new(Arc::new(None)),
61:            .time_zone((**self.time_zone.load()).clone())
76:    pub fn time_zone(&self) -> Option<TimeZone> {
77:        self.time_zone.load().as_ref().clone()
81:    pub fn set_time_zone(&self, tz: Option<TimeZone>) {
82:        let _ = self.time_zone.swap(Arc::new(tz));

[killme2008]

Do we need to process these convertions?

greptimedb/src/datatypes/src/value.rs

Line 390 in 1641fd5

TimeUnit::Second => ScalarValue::TimestampSecond(val, None),

greptimedb/src/common/query/src/logical_plan/expr.rs

Line 83 in 1641fd5

TimeUnit::Second => ScalarValue::TimestampSecond(Some(timestamp.value()), None),

Attach the timezone to the scalar value of datafusion.

[Taylor-lagrange]

According to my observation, these case are used in calculation(all timestamp are convert to UTC to calculate and store, so no timezone info is fine), or the input is a i64 timestamp without timezone info ( such as prepare stmt's variable). We may need not dispose these situation, just leave it empty.

[killme2008]

LGTM