Online DDL: removal of gh-ost and pt-osc strategies (#17626)

Signed-off-by: Shlomi Noach <[email protected]>

changelog/22.0/22.0.0/summary.md

@@ -5,6 +5,7 @@
 - **[Major Changes](#major-changes)**
   - **[Deprecations and Deletions](#deprecations-and-deletions)**
     - [Deprecated VTTablet Flags](#vttablet-flags)
+    - [Removing gh-ost and pt-osc Online DDL strategies](#ghost-ptosc)
   - **[RPC Changes](#rpc-changes)**
   - **[Prefer not promoting a replica that is currently taking a backup](#reparents-prefer-not-backing-up)**
   - **[VTOrc Config File Changes](#vtorc-config-file-changes)**
@@ -38,6 +39,21 @@ These are the RPC changes made in this release -
 
 - `twopc_enable` flag is deprecated. Usage of TwoPC commit will be determined by the `transaction_mode` set on VTGate via flag or session variable.
 
+#### <a id="ghost-ptosc"/>Removing gh-ost and pt-osc Online DDL strategies</a>
+
+Vitess no longer recognizes the `gh-ost` and `pt-osc` (`pt-online-schema-change`) Online DDL strategies. The `vitess` strategy is the recommended way to make schema changes at scale. `mysql` and `direct` strategies continue to be supported.
+
+These `vttablet` flags have been removed:
+
+- `--gh-ost-path`
+- `--pt-osc-path`
+
+The use of `gh-ost` and `pt-osc` as strategies as follows, yields an error:
+```sh
+$ vtctldclient ApplySchema --ddl-strategy="gh-ost" ...
+$ vtctldclient ApplySchema --ddl-strategy="pt-osc" ...
+```
+
 ### <a id="reparents-prefer-not-backing-up"/>Prefer not promoting a replica that is currently taking a backup
 
 Emergency reparents now prefer not promoting replicas that are currently taking backups with a backup engine other than

go/cmd/vtctldclient/command/schema.go

@@ -45,7 +45,7 @@ var (
 		Long: `Applies the schema change to the specified keyspace on every primary, running in parallel on all shards. The changes are then propagated to replicas via replication.
 
 If --allow-long-unavailability is set, schema changes affecting a large number of rows (and possibly incurring a longer period of unavailability) will not be rejected.
---ddl-strategy is used to instruct migrations via vreplication, gh-ost or pt-osc with optional parameters.
+--ddl-strategy is used to instruct migrations via vreplication, mysql or direct with optional parameters.
 --migration-context allows the user to specify a custom migration context for online DDL migrations.
 If --skip-preflight, SQL goes directly to shards without going through sanity checks.
 
@@ -430,7 +430,7 @@ func commandValidateSchemaShard(cmd *cobra.Command, args []string) error {
 }
 
 func init() {
-	ApplySchema.Flags().StringVar(&applySchemaOptions.DDLStrategy, "ddl-strategy", string(schema.DDLStrategyDirect), "Online DDL strategy, compatible with @@ddl_strategy session variable (examples: 'gh-ost', 'pt-osc', 'gh-ost --max-load=Threads_running=100'.")
+	ApplySchema.Flags().StringVar(&applySchemaOptions.DDLStrategy, "ddl-strategy", string(schema.DDLStrategyDirect), "Online DDL strategy, compatible with @@ddl_strategy session variable (examples: 'direct', 'mysql', 'vitess --postpone-completion'.")
 	ApplySchema.Flags().StringSliceVar(&applySchemaOptions.UUIDList, "uuid", nil, "Optional, comma-delimited, repeatable, explicit UUIDs for migration. If given, must match number of DDL changes.")
 	ApplySchema.Flags().StringVar(&applySchemaOptions.MigrationContext, "migration-context", "", "For Online DDL, optionally supply a custom unique string used as context for the migration(s) in this command. By default a unique context is auto-generated by Vitess.")
 	ApplySchema.Flags().DurationVar(&applySchemaOptions.WaitReplicasTimeout, "wait-replicas-timeout", grpcvtctldserver.DefaultWaitReplicasTimeout, "Amount of time to wait for replicas to receive the schema change via replication.")

go/flags/endtoend/vtcombo.txt

@@ -136,7 +136,6 @@ Flags:
       --gate_query_cache_memory int                                      gate server query cache size in bytes, maximum amount of memory to be cached. vtgate analyzes every incoming query and generate a query plan, these plans are being cached in a lru cache. This config controls the capacity of the lru cache. (default 33554432)
       --gc_check_interval duration                                       Interval between garbage collection checks (default 1h0m0s)
       --gc_purge_check_interval duration                                 Interval between purge discovery checks (default 1m0s)
-      --gh-ost-path string                                               override default gh-ost binary full path (default "gh-ost")
       --grpc-send-session-in-streaming                                   If set, will send the session as last packet in streaming api to support transactions in streaming
       --grpc-use-effective-groups                                        If set, and SSL is not used, will set the immediate caller's security groups from the effective caller id's groups.
       --grpc-use-static-authentication-callerid                          If set, will set the immediate caller id to the username authenticated by the static auth plugin.
@@ -265,7 +264,6 @@ Flags:
       --proto_topo vttest.TopoData                                       vttest proto definition of the topology, encoded in compact text format. See vttest.proto for more information.
       --proxy_protocol                                                   Enable HAProxy PROXY protocol on MySQL listener socket
       --proxy_tablets                                                    Setting this true will make vtctld proxy the tablet status instead of redirecting to them
-      --pt-osc-path string                                               override default pt-online-schema-change binary full path (default "/usr/bin/pt-online-schema-change")
       --publish_retry_interval duration                                  how long vttablet waits to retry publishing the tablet record (default 30s)
       --purge_logs_interval duration                                     how often try to remove old logs (default 1h0m0s)
       --query-log-stream-handler string                                  URL handler for streaming queries log (default "/debug/querylog")

go/flags/endtoend/vttablet.txt

@@ -162,7 +162,6 @@ Flags:
       --gc_purge_check_interval duration                                 Interval between purge discovery checks (default 1m0s)
       --gcs_backup_storage_bucket string                                 Google Cloud Storage bucket to use for backups.
       --gcs_backup_storage_root string                                   Root prefix for all backup-related object names.
-      --gh-ost-path string                                               override default gh-ost binary full path (default "gh-ost")
       --grpc-dial-concurrency-limit int                                  Maximum concurrency of grpc dial operations. This should be less than the golang max thread limit of 10000. (default 1024)
       --grpc_auth_mode string                                            Which auth plugin implementation to use (eg: static)
       --grpc_auth_mtls_allowed_substrings string                         List of substrings of at least one of the client certificate names (separated by colon).
@@ -259,7 +258,6 @@ Flags:
       --port int                                                         port for the server
       --pprof strings                                                    enable profiling
       --pprof-http                                                       enable pprof http endpoints
-      --pt-osc-path string                                               override default pt-online-schema-change binary full path (default "/usr/bin/pt-online-schema-change")
       --publish_retry_interval duration                                  how long vttablet waits to retry publishing the tablet record (default 30s)
       --purge_logs_interval duration                                     how often try to remove old logs (default 1h0m0s)
       --query-log-stream-handler string                                  URL handler for streaming queries log (default "/debug/querylog")