From ced60b03893aee5f0522d074ece16c10bedf050f Mon Sep 17 00:00:00 2001
From: Yang Xiufeng <yangxiufeng.c@gmail.com>
Date: Fri, 14 Nov 2025 23:01:14 +0800
Subject: [PATCH] refactor: improve decode of timestamp

---
 sql/src/value/arrow_decoder.rs | 26 ++++++++++----------------
 sql/src/value/convert.rs       | 24 ++++++++----------------
 sql/src/value/format.rs        |  7 +------
 3 files changed, 19 insertions(+), 38 deletions(-)

diff --git a/sql/src/value/arrow_decoder.rs b/sql/src/value/arrow_decoder.rs
index a39d49cc..503137ea 100644
--- a/sql/src/value/arrow_decoder.rs
+++ b/sql/src/value/arrow_decoder.rs
@@ -22,7 +22,7 @@ use arrow_array::{
     StructArray, TimestampMicrosecondArray, UInt16Array, UInt32Array, UInt64Array, UInt8Array,
 };
 use arrow_schema::{DataType as ArrowDataType, Field as ArrowField, TimeUnit};
-use chrono::{DateTime, FixedOffset};
+use chrono::{FixedOffset, TimeZone};
 use chrono_tz::Tz;
 use databend_client::schema::{
     DecimalSize, ARROW_EXT_TYPE_BITMAP, ARROW_EXT_TYPE_EMPTY_ARRAY, ARROW_EXT_TYPE_EMPTY_MAP,
@@ -92,22 +92,16 @@ impl TryFrom<(&ArrowField, &Arc<dyn ArrowArray>, usize, Tz)> for Value {
                     match array.as_any().downcast_ref::<Decimal128Array>() {
                         Some(array) => {
                             let v = array.value(seq);
-                            let ts = v as u64 as i64;
+                            let unix_ts = v as u64 as i64;
                             let offset = (v >> 64) as i32;
-
-                            let secs = ts / 1_000_000;
-                            let nanos = ((ts % 1_000_000) * 1000) as u32;
-                            let dt = match DateTime::from_timestamp(secs, nanos) {
-                                Some(t) => {
-                                    let off = FixedOffset::east_opt(offset).ok_or_else(|| {
-                                        Error::Parsing("invalid offset".to_string())
-                                    })?;
-                                    t.with_timezone(&off)
-                                }
-                                None => {
-                                    return Err(ConvertError::new("Datetime", format!("{v}")).into())
-                                }
-                            };
+                            let offset = FixedOffset::east_opt(offset)
+                                .ok_or_else(|| Error::Parsing("invalid offset".to_string()))?;
+                            let dt =
+                                offset.timestamp_micros(unix_ts).single().ok_or_else(|| {
+                                    Error::Parsing(format!(
+                                        "Invalid timestamp_micros {unix_ts} for offset {offset}"
+                                    ))
+                                })?;
                             Ok(Value::TimestampTz(dt))
                         }
                         None => Err(ConvertError::new("Interval", format!("{array:?}")).into()),
diff --git a/sql/src/value/convert.rs b/sql/src/value/convert.rs
index 330a5d23..e3074f88 100644
--- a/sql/src/value/convert.rs
+++ b/sql/src/value/convert.rs
@@ -109,14 +109,10 @@ impl TryFrom<Value> for NaiveDateTime {
     type Error = Error;
     fn try_from(val: Value) -> Result<Self> {
         match val {
-            Value::Timestamp(i, _tz) => {
-                let secs = i / 1_000_000;
-                let nanos = ((i % 1_000_000) * 1000) as u32;
-                match DateTime::from_timestamp(secs, nanos) {
-                    Some(t) => Ok(t.naive_utc()),
-                    None => Err(ConvertError::new("NaiveDateTime", format!("{val}")).into()),
-                }
-            }
+            Value::Timestamp(i, _tz) => match DateTime::from_timestamp_micros(i) {
+                Some(t) => Ok(t.naive_utc()),
+                None => Err(ConvertError::new("NaiveDateTime", format!("{val}")).into()),
+            },
             _ => Err(ConvertError::new("NaiveDateTime", format!("{val}")).into()),
         }
     }
@@ -126,14 +122,10 @@ impl TryFrom<Value> for DateTime<Tz> {
     type Error = Error;
     fn try_from(val: Value) -> Result<Self> {
         match val {
-            Value::Timestamp(i, tz) => {
-                let secs = i / 1_000_000;
-                let nanos = ((i % 1_000_000) * 1000) as u32;
-                match DateTime::from_timestamp(secs, nanos) {
-                    Some(t) => Ok(tz.from_utc_datetime(&t.naive_utc())),
-                    None => Err(ConvertError::new("Datetime", format!("{val}")).into()),
-                }
-            }
+            Value::Timestamp(i, tz) => match DateTime::from_timestamp_micros(i) {
+                Some(t) => Ok(tz.from_utc_datetime(&t.naive_utc())),
+                None => Err(ConvertError::new("Datetime", format!("{val}")).into()),
+            },
             _ => Err(ConvertError::new("DateTime", format!("{val}")).into()),
         }
     }
diff --git a/sql/src/value/format.rs b/sql/src/value/format.rs
index 22d0901a..83dfed8b 100644
--- a/sql/src/value/format.rs
+++ b/sql/src/value/format.rs
@@ -74,12 +74,7 @@ fn encode_value(f: &mut std::fmt::Formatter<'_>, val: &Value, raw: bool) -> std:
             }
         }
         Value::Timestamp(micros, _tz) => {
-            let (mut secs, mut nanos) = (*micros / 1_000_000, (*micros % 1_000_000) * 1_000);
-            if nanos < 0 {
-                secs -= 1;
-                nanos += 1_000_000_000;
-            }
-            let t = DateTime::from_timestamp(secs, nanos as _).unwrap_or_default();
+            let t = DateTime::from_timestamp_micros(*micros).unwrap_or_default();
             let t = t.naive_utc();
             if raw {
                 write!(f, "{}", t.format(TIMESTAMP_FORMAT))