[update] Schema and Hypertable (#2613)

* add a word about timestamptz over timestamp

* incorporated the review comments

Signed-off-by: Rajakavitha Kodhandapani <krajakavitha@gmail.com>

---------

Signed-off-by: Rajakavitha Kodhandapani <krajakavitha@gmail.com>
Co-authored-by: Lana Brindley <github@lanabrindley.com>

use-timescale/hypertables/create.md

@@ -22,7 +22,9 @@ To create a hypertable, you need to create a standard PostgreSQL table, and then
 convert it into a hypertable.
 
 Hypertables are intended for time-series data, so your table needs a column that
-holds time values. This can be a timestamp, date, or integer.
+holds time values. This can be a timestamptz, date, or integer. Ensure that you
+set the datatype for the `time` column as `timestamptz` and not `timestamp`. For
+more information, see [PostgreSQL timestamp][postgresql-timestamp].
 
 <Procedure>
 
@@ -60,3 +62,4 @@ data. For more information about migrating data, see the
 [create-distributed-hypertable]: /self-hosted/:currentVersion:/distributed-hypertables/create-distributed-hypertables/
 [install]: /getting-started/latest/
 [postgres-createtable]: https://www.postgresql.org/docs/current/sql-createtable.html
+[postgresql-timestamp]: https://wiki.postgresql.org/wiki/Don't_Do_This#Don.27t_use_timestamp_.28without_time_zone.29

use-timescale/schema-management/about-indexing.md

@@ -12,6 +12,9 @@ data in your hypertable, you can use an index to speed up read operations. You
 can create an index on any combination of columns, as long as you include the
 `time` column, for time-series data. Which column you choose to create your
 index on depends on what kind of data you have stored.
+When you create a hypertable, set the datatype for the `time` column as
+`timestamptz` and not `timestamp`.
+For more information, see [PostgreSQL timestamp][postgresql-timestamp].
 
 <Highlight type="note">
 While it is possible to add an index that does not include the `time` column,
@@ -120,3 +123,5 @@ SELECT * FROM devices WHERE store_id = M, device_id = M, time > 10
 
 This is an accurate query for this index. It narrows down the list to a very
 specific portion.
+
+[postgresql-timestamp]: https://wiki.postgresql.org/wiki/Don't_Do_This#Don.27t_use_timestamp_.28without_time_zone.29

use-timescale/schema-management/about-schemas.md

@@ -17,9 +17,13 @@ that collect varying measurements, you might need a flexible schema. In this
 case, you can use PostgreSQL JSON and JSONB data types.
 
 Timescale supports all table objects supported within PostgreSQL, including
-data types, indexes, and triggers.
+data types, indexes, and triggers. However, when you create a hypertable, set the
+datatype for the `time` column as `timestamptz` and not `timestamp`. For more
+information, see [PostgreSQL timestamp][postgresql-timestamp].
 
 This section explains how to design your schema, how indexing and tablespaces
 work, and how to use PostgreSQL constraint types. It also includes examples to
 help you create your own schema, and learn how to use JSON and JSONB for
 semi-structured data.
+
+[postgresql-timestamp]: https://wiki.postgresql.org/wiki/Don't_Do_This#Don.27t_use_timestamp_.28without_time_zone.29