From 6f5709ee08118deabd9ea14cbb8dc429ae4b9abb 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 1cc22a11cfda7..9de494baa3fda 100644 --- a/glossary.md +++ b/glossary.md @@ -20,18 +20,38 @@ 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 23db9868fe67544905aae85bcea3b02d03f0acf3 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 9de494baa3fda..f6c22fb225102 100644 --- a/glossary.md +++ b/glossary.md @@ -22,6 +22,10 @@ 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). @@ -93,6 +97,12 @@ 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 a78f38b3fef8e9cfb6e03d4b69e5d30ba5d8374b 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 5f43c2af87f32..de61096efdf17 100644 --- a/glossary.md +++ b/glossary.md @@ -28,7 +28,7 @@ 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