update

_docs/en/administration/backup-request.md

@@ -3,7 +3,7 @@ permalink: administration/backup-request
 ---
 
 # Background
-In the current implementation of Pegasus, reading from secondary replicas can cause inconsistencies, so Pegasus currently only supports reading from primary replicas. However, in certain situations (such as load balancing, hotspot writes, etc.), the primary can often become unstable. Therefore, we hope to read from the secondary when the primary is unstable, sacrificing some strong consistency to reduce the tail latency of read requests and improve system availability. Backup request is designed to achieve this functionality.
+In the current implementation of Pegasus, reading from secondary replicas can cause inconsistencies, so Pegasus defaults reading from primary replicas. However, in certain situations (such as load balancing, hotspot writes, etc.), the primary can often become unstable. Therefore, we hope to read from the secondary when the primary is unstable, sacrificing some strong consistency to reduce the tail latency of read requests and improve system availability. Backup request is designed to achieve this functionality.
 
 # Design and Implementation
 
@@ -21,13 +21,13 @@ Compared to the old version of the `openTable` interface, we have added a `backu
 
 In addition, in the old version of the `openTable` interface, the backup request feature is disabled by default.
 
-# Performance Testing
+# Benchmark
 
 The following table shows the performance comparison of whether the backup request is enabled. Here we selected the p999 time of read requests when the backup request is not enabled as the delay time for the backup request (138ms). The data shows that after enabling the backup request, the p999 latency of get requests **remains almost unchanged**, while the p9999 latency is **reduced by several times**.
 
 In addition, since the delay time is set to p999 time, about 1 out of 1000 requests will send a backup request, so the proportion of additional request volume (i.e., the additional overhead of enabling the backup request) is about 0.1%. By analogy, if you want to reduce P999 latency, you can set `backupRequestDelayMs` to P99 latency, which will increase the additional read traffic by 1%.
 
-| test case            | enable backup request | read p9999 |
-|----------------------|-----------------------|------------|
-| 3-clients 15-threads | no                    | 988671     |
-| 3-clients 15-threads | yes                   | 153599     |
+| test case            | enable backup request | read p9999 latency in microsecond |
+|----------------------|-----------------------|-----------------------------------|
+| 3-clients 15-threads | no                    | 988,671                           |
+| 3-clients 15-threads | yes                   | 153,599                           |

_docs/zh/administration/backup-request.md

@@ -3,7 +3,7 @@ permalink: administration/backup-request
 ---
 
 # 背景
-在当前的 Pegasus 实现中，由于向 secondary 读取会导致不一致的情况发生，所以目前 Pegasus 仅支持对 primary 副本的读取。但是在某些情况下（例如：负载均衡、热点写入等）经常会导致 primary 不稳定。因此，我们希望在 primary 不稳定时能够读取 secondary，通过牺牲部分强一致性来降低读请求的长尾并提高系统的可用性。backup request 便是用来实现此功能的。
+在当前的 Pegasus 实现中，由于向 secondary 读取会导致不一致的情况发生，所以 Pegasus 默认只对 primary 副本的读取。但是在某些情况下（例如：负载均衡、热点写入等）经常会导致 primary 不稳定。因此，我们希望在 primary 不稳定时能够读取 secondary，通过牺牲部分强一致性来降低读请求的长尾并提高系统的可用性。backup request 便是用来实现此功能的。
 
 # 设计实现
 
@@ -21,13 +21,13 @@ public PegasusTableInterface openTable(String tableName, int backupRequestDelayM
 
 另外在老版本的 `openTable` 接口中，backup request 功能默认是关闭的。
 
-# 性能测试
+# Benchmark
 
 下面表格里展示了是否打开 backup request 的性能对比，这里我们选取了未打开 backup request 时读请求的 p999 时间作为 backup request 的 delay 时间（138ms）。数据显示，打开 backup request 之后 get 请求的 p999 时延**基本没有变化**，而 p9999 时延却有了**数倍的降低**。
 
 另外，由于 delay 时间设置的是 p999 时间，大约 1000 个请求里只有 1 个请求会发送 backup request，因此额外请求量（也就是开启 backup request 的额外开销）比例在 0.1% 左右。依此类推，若想要降低 P999 时延，则可以将 `backupRequestDelayMs` 设置为 P99 延迟，由此会增加 1% 的额外读流量。
 
-| test case            | enable backup request | read p9999 |
-|----------------------|-----------------------|------------|
-| 3-clients 15-threads | no                    | 988671     |
-| 3-clients 15-threads | yes                   | 153599     |
+| test case            | enable backup request | read p9999 latency in microsecond |
+|----------------------|-----------------------|-----------------------------------|
+| 3-clients 15-threads | no                    | 988,671                           |
+| 3-clients 15-threads | yes                   | 153,599                           |