tidb removed 代码
文件路径：/sessionctx/variable/removed.go
/ Copyright 2021 PingCAP, Inc.
/
/ Licensed under the Apache License, Version 2.0 (the "License");
/ you may not use this file except in compliance with the License.
/ You may obtain a copy of the License at
/
/ http://www.apache.org/licenses/LICENSE-2.0
/
/ Unless required by applicable law or agreed to in writing, software
/ distributed under the License is distributed on an "AS IS" BASIS,
/ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/ See the License for the specific language governing permissions and
/ limitations under the License.
package variable
/ Removed sysvars is a way of removing sysvars, while allowing limited
/ Parse-but-ignore support in SET context, and a more specific error in
/ SELECT @@varname context.
/
/ This helps ensure some compatibility for applications while being
/ careful not to return dummy data.
const (
tiDBEnableAlterPlacement = "tidb_enable_alter_placement"
tiDBMemQuotaHashJoin = "tidb_mem_quota_hashjoin"
tiDBMemQuotaMergeJoin = "tidb_mem_quota_mergejoin"
tiDBMemQuotaSort = "tidb_mem_quota_sort"
tiDBMemQuotaTopn = "tidb_mem_quota_topn"
tiDBMemQuotaIndexLookupReader = "tidb_mem_quota_indexlookupreader"
tiDBMemQuotaIndexLookupJoin = "tidb_mem_quota_indexlookupjoin"
tiDBEnableGlobalTemporaryTable = "tidb_enable_global_temporary_table"
tiDBSlowLogMasking = "tidb_slow_log_masking"
placementChecks = "placement_checks"
tiDBEnableStreaming = "tidb_enable_streaming"
tiDBOptBCJ = "tidb_opt_broadcast_join"
tidbEnableChangeMultiSchema = "tidb_enable_change_multi_schema"
)
var removedSysVars = map[string]string{
tiDBEnableAlterPlacement: "alter placement is now always enabled",
tiDBEnableGlobalTemporaryTable: "temporary table support is now always enabled",
tiDBSlowLogMasking: "use tidb_redact_log instead",
placementChecks: "placement_checks is removed and use tidb_placement_mode instead",
tiDBMemQuotaHashJoin: "use tidb_mem_quota_query instead",
tiDBMemQuotaMergeJoin: "use tidb_mem_quota_query instead",
tiDBMemQuotaSort: "use tidb_mem_quota_query instead",
tiDBMemQuotaTopn: "use tidb_mem_quota_query instead",
tiDBMemQuotaIndexLookupReader: "use tidb_mem_quota_query instead",
tiDBMemQuotaIndexLookupJoin: "use tidb_mem_quota_query instead",
tiDBEnableStreaming: "streaming is no longer supported",
tiDBOptBCJ: "tidb_opt_broadcast_join is removed and use tidb_allow_mpp instead",
tidbEnableChangeMultiSchema: "alter multiple schema objects in a table is now always enabled",
}
/ IsRemovedSysVar returns true if the sysvar has been removed
func IsRemovedSysVar(varName string) bool {
_, ok := removedSysVars[varName]
return ok
}
/ CheckSysVarIsRemoved returns an error if the sysvar has been removed
func CheckSysVarIsRemoved(varName string) error {
if reason, ok := removedSysVars[varName]; ok {
return ErrVariableNoLongerSupported.GenWithStackByArgs(varName, reason)
}
return nil
}