updated documentation with latest update on default collations

Signed-off-by: Florent Poinsard <florent.poinsard@outlook.fr>
vitessio · Nov 17, 2021 · 897da3f · 897da3f
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diff --git a/content/en/docs/reference/programs/vtgate.md b/content/en/docs/reference/programs/vtgate.md
@@ -44,7 +44,6 @@ The following global options apply to `vtgate`:
 | -buffer_window | duration | Duration for how long a request should be buffered at most. (default 10s) |
 | -cell | string | cell to use (default "test_nj") |
 | -cells_to_watch | string | comma-separated list of cells for watching tablets |
-| -collation | string | Collation to use between VTGate and VTTablet. If this flag is not defined, the default collation of utf8mb4 for your backend database will be used. |
 | -consul_auth_static_file | string | JSON File to read the topos/tokens from. |
 | -cpu_profile | string | write cpu profile to file |
 | -datadog-agent-host | string | host to send spans to. if empty, no tracing will be done |

diff --git a/content/en/docs/user-guides/vschema-guide/collations.md b/content/en/docs/user-guides/vschema-guide/collations.md
@@ -12,18 +12,17 @@ Vitess uses collations to compare strings the same way that MySQL uses `@collati
 
 #### VTGate
 
-At the VTGate level we use the `-collation` flag to specify which collation we want to use.
-Leaving this flag empty will result in VTGate picking the default collation of the `utf8mb4` charset.
-
-The default collation of charsets varies depending on the backend database and its version.
-For instance, the default collation for `utf8mb4` is `utf8mb4_general_ci` on MySQL57 and `utf8mb4_0900_ai_ci` on MySQL80.
-For this reason, VTTablet is responsible for notifying VTGate which backend version of MySQL/MariaDB we are using.
-This is done through health-check at start time.
+The default collation of VTGate depends on VTTablet.
+Through health-checks, VTGate receives the collation it needs to use.
 
 #### VTTablet
 
 VTTablet's collation and charset can respectively be set with `-db_collation` and `-db_charset`.
-In a similar fashion as what we do in VTGate, using the backend database version, the charset defaults to `utf8mb4`, while the collation can be left empty, in which case the default collation of the charset will be picked.
+If the `-db_collation` flag is empty, we choose the collation using the charset based on the backend database version (MySQL80, MySQL57, ...), the charset defaults to `utf8mb4`.
+
+> The default collation of charsets varies depending on the backend database and its version.
+> 
+> For instance, the default collation for `utf8mb4` is `utf8mb4_general_ci` on MySQL57 and `utf8mb4_0900_ai_ci` on MySQL80.
 
 ### Internals