sync documentation, add remark about to_timestamp and redshift (#9841)

docs/sources/features/datasources/postgres.md

@@ -45,10 +45,10 @@ Macro example | Description
 ------------ | -------------
 *$__time(dateColumn)* | Will be replaced by an expression to rename the column to `time`. For example, *dateColumn as time*
 *$__timeSec(dateColumn)* | Will be replaced by an expression to rename the column to `time` and converting the value to unix timestamp. For example, *extract(epoch from dateColumn) as time*
-*$__timeFilter(dateColumn)* | Will be replaced by a time range filter using the specified column name. For example, *dateColumn > to_timestamp(1494410783) AND dateColumn < to_timestamp(1494497183)*
+*$__timeFilter(dateColumn)* | Will be replaced by a time range filter using the specified column name. For example, *extract(epoch from dateColumn) BETWEEN 1494410783 AND 1494497183*
 *$__timeFrom()* | Will be replaced by the start of the currently active time selection. For example, *to_timestamp(1494410783)*
 *$__timeTo()* | Will be replaced by the end of the currently active time selection. For example, *to_timestamp(1494497183)*
-*$__timeGroup(dateColumn,'5m')* | Will be replaced by an expression usable in GROUP BY clause. For example, *(extract(epoch from "dateColumn")/extract(epoch from '5m'::interval))::int*extract(epoch from '5m'::interval)*
+*$__timeGroup(dateColumn,'5m')* | Will be replaced by an expression usable in GROUP BY clause. For example, *(extract(epoch from "dateColumn")/300)::bigint*300*
 *$__unixEpochFilter(dateColumn)* | Will be replaced by a time range filter using the specified column name with times represented as unix timestamp. For example, *dateColumn > 1494410783 AND dateColumn < 1494497183*
 *$__unixEpochFrom()* | Will be replaced by the start of the currently active time selection as unix timestamp. For example, *1494410783*
 *$__unixEpochTo()* | Will be replaced by the end of the currently active time selection as unix timestamp. For example, *1494497183*

pkg/tsdb/postgres/macros.go

@@ -72,6 +72,7 @@ func (m *PostgresMacroEngine) evaluateMacro(name string, args []string) (string,
 		}
 		return fmt.Sprintf("extract(epoch from %s) as \"time\"", args[0]), nil
 	case "__timeFilter":
+		// dont use to_timestamp in this macro for redshift compatibility #9566
 		if len(args) == 0 {
 			return "", fmt.Errorf("missing time column argument for macro %v", name)
 		}

public/app/plugins/datasource/postgres/partials/query.editor.html

@@ -48,9 +48,9 @@ Table:
 Macros:
 - $__time(column) -> column as "time"
 - $__timeEpoch -> extract(epoch from column) as "time"
-- $__timeFilter(column) ->  column ≥ to_timestamp(1492750877) AND column ≤ to_timestamp(1492750877)
+- $__timeFilter(column) ->  extract(epoch from column) BETWEEN 1492750877 AND 1492750877
 - $__unixEpochFilter(column) ->  column > 1492750877 AND column < 1492750877
-- $__timeGroup(column,'5m') -> (extract(epoch from "dateColumn")/extract(epoch from '5m'::interval))::int
+- $__timeGroup(column,'5m') -> (extract(epoch from "dateColumn")/300)::bigint*300
 
 Example of group by and order by with $__timeGroup:
 SELECT