From e17d842a94c651629c67f5cfb2ae7a1fb08e455e Mon Sep 17 00:00:00 2001 From: Ran Date: Tue, 29 Mar 2022 15:56:01 +0800 Subject: [PATCH 1/3] add 6.0 terms in glossary Signed-off-by: Ran --- glossary.md | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/glossary.md b/glossary.md index 72c7cb54f0c8f..2005d60aed69b 100644 --- a/glossary.md +++ b/glossary.md @@ -19,18 +19,38 @@ ACID refers to the four key properties of a transaction: atomicity, consistency, - **Durability** means that once a transaction is committed, it remains committed even in the event of a system failure. TiKV uses persistent storage to ensure durability. +## B + +### Baseline Capturing + +Baseline Capturing captures queries that meet capturing conditions and create bindings for them. It is used for [preventing rollback of execution plans during an upgrade](/sql-plan-management.md#prevent-rollback-of-execution-plans-during-an-upgrade). + ## C +### Cached Table + +With the cached table feature, TiDB loads the data of an entire table into the memory of the TiDB server, and TiDB directly gets the table data from the memory without accessing TiKV, which improves the read performance. + ### Continuous Profiling Introduced in TiDB 5.3.0, Continuous Profiling is a way to observe resource overhead at the system call level. With the support of Continuous Profiling, TiDB provides performance insight as clear as directly looking into the database source code, and helps R&D and operation and maintenance personnel to locate the root cause of performance problems using a flame graph. For details, see [TiDB Dashboard Instance Profiling - Continuous Profiling](/dashboard/continuous-profiling.md). +## D + +### Dynamic Pruning + +Dynamic proning mode is one of the modes that TiDB accesses partitioned tables. In dynamic pruning mode, each operator supports direct access to multiple partitions. Therefore, TiDB no longer uses Union. Omitting the Union operation can improve the execution efficiency and avoid the problem of Union concurrent execution. + ## I ### Index Merge Index Merge is a method introduced in TiDB v4.0 to access tables. Using this method, the TiDB optimizer can use multiple indexes per table and merge the results returned by each index. In some scenarios, this method makes the query more efficient by avoiding full table scans. Since v5.4, Index Merge has become a GA feature. +### In-Memory Pessimistic Lock + +The in-memory pessimistic lock is a new feature introduced in TiDB v6.0.0. When this feature is enabled, pessimistic locks are usually stored in the memory of the Region leader only, and are not persisted to disk or replicated through Raft to other replicas. This feature can greatly reduce the overhead of acquiring pessimistic locks and improve the throughput of pessimistic transactions. + ## L ### leader/follower/learner From 91c28825ae3669bc6c9ebf2afe826124ca92325e Mon Sep 17 00:00:00 2001 From: en-jin19 Date: Sat, 2 Apr 2022 13:55:24 +0800 Subject: [PATCH 2/3] add two parts --- glossary.md | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/glossary.md b/glossary.md index 2005d60aed69b..84418e6ed4c74 100644 --- a/glossary.md +++ b/glossary.md @@ -21,6 +21,10 @@ ACID refers to the four key properties of a transaction: atomicity, consistency, ## B +### Batch Create Table + +Batch Create Table is a feature introduced in TiDB v6.0.0. This feature is enabled default. When restoring data with a large number of tables (nearly 50000) using BR (Backup & Restore), the feature can greatly speed up the restore process by creating tables in batches. For details, see [Batch Create Table](/br/br-batch-create-table.md). + ### Baseline Capturing Baseline Capturing captures queries that meet capturing conditions and create bindings for them. It is used for [preventing rollback of execution plans during an upgrade](/sql-plan-management.md#prevent-rollback-of-execution-plans-during-an-upgrade). @@ -92,6 +96,12 @@ Currently, available steps generated by PD include: In most cases, when executing SQL statements, the optimizer only uses statistics of some columns (such as columns in the `WHERE`, `JOIN`, `ORDER BY`, and `GROUP BY` statements). These used columns are called predicate columns. For details, see [Collect statistics on some columns](/statistics.md#collect-statistics-on-some-columns). +## Q + +### Quota Limiter + +Quota Limiter is an experimental feature introduced in TiDB v6.0.0. If the machine on which TiKV is deployed has limited resources, for example, with only 4v CPU and 16 G memory, and the foreground of TiKV processes too many read and write requests, the CPU resources used by the background are occupied to help process such requests, which affects the performance stability of TiKV. To avoid this situation, the [quota-related configuration items](/tikv-configuration-file.md#quota) can be set to limit the CPU resources to be used by the foreground. + ## R ## Raft Engine From e23fa3a37feb31b1a52f6e63117ff558db935f4e Mon Sep 17 00:00:00 2001 From: Ran Date: Wed, 6 Apr 2022 10:50:04 +0800 Subject: [PATCH 3/3] update anchor Signed-off-by: Ran --- glossary.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/glossary.md b/glossary.md index 84418e6ed4c74..9839d373964d4 100644 --- a/glossary.md +++ b/glossary.md @@ -27,7 +27,7 @@ Batch Create Table is a feature introduced in TiDB v6.0.0. This feature is enabl ### Baseline Capturing -Baseline Capturing captures queries that meet capturing conditions and create bindings for them. It is used for [preventing rollback of execution plans during an upgrade](/sql-plan-management.md#prevent-rollback-of-execution-plans-during-an-upgrade). +Baseline Capturing captures queries that meet capturing conditions and create bindings for them. It is used for [preventing regression of execution plans during an upgrade](/sql-plan-management.md#prevent-regression-of-execution-plans-during-an-upgrade). ## C