From 2582f1f2445eea63bdc8208e207489e6548b334a Mon Sep 17 00:00:00 2001 From: Philipp Heckel Date: Tue, 27 Jul 2021 08:47:06 -0400 Subject: [PATCH] Minor docs updates --- docs/configuration-discovery-classifying.md | 14 +++++++------- docs/failure-detection.md | 2 +- 2 files changed, 8 insertions(+), 8 deletions(-) diff --git a/docs/configuration-discovery-classifying.md b/docs/configuration-discovery-classifying.md index 5220683ca..4ce22c439 100644 --- a/docs/configuration-discovery-classifying.md +++ b/docs/configuration-discovery-classifying.md @@ -90,21 +90,21 @@ This behavior can be controlled by the following options: and `MasterWithTooManyReplicas` will enable _and disable_ semi-sync on the replicas to match the desired topology exactly based on the priority order. - `RecoverLockedSemiSyncMaster`: flag that decides whether to recover from a `LockedSemiSyncMaster` scenario. If enabled, the recovery of `LockedSemiSyncMaster` will enable _(but never disable)_ semi-sync on the replicas in the priority order to match the master wait count. This option has no effect if - `EnforceExactSemiSyncReplicas` is set. It is only useful if you'd like to only handle a situation which which there are too few semi-sync replicas, + `EnforceExactSemiSyncReplicas` is set. It is useful if you'd like to only handle a situation in which there are too few semi-sync replicas, but not if there are too many. - `ReasonableLockedSemiSyncMasterSeconds`: number of seconds after which the `LockedSemiSyncMaster` condition is triggered; if not set, falls back to `ReasonableReplicationLagSeconds` The priority order is defined by `DetectSemiSyncEnforcedQuery` (zero means async replica; higher number is higher priority), the promotion rule (`DetectPromotionRuleQuery`) and the hostname (fallback). -**Example 1**: Enforcing a strict semi-sync replica topology with two replicas and `rpl_semi_sync_master_wait_for_slave_count=1`: +**Example 1**: Enforcing a strict semi-sync replica topology, with `rpl_semi_sync_master_wait_for_slave_count=1`: ``` "DetectSemiSyncEnforcedQuery": "select priority from meta.semi_sync where cluster_member = @@hostname", "EnforceExactSemiSyncReplicas": true ``` -Assuming this topology: +Assuming this topology, ``` ,- replica1 (priority = 10, rpl_semi_sync_slave_enabled = 1) @@ -113,9 +113,9 @@ Assuming this topology: ``` `orchestrator` would detect a [`MasterWithTooManySemiSyncReplicas`](failure-detection.md#masterwithtoomanysemisyncreplicas) scenario -and disable semi-sync on replica2. +and disable semi-sync on replica1 (lower priority). -**Example 2**: Enforcing a weak semi-sync replica toplogy with two replicas and `rpl_semi_sync_master_wait_for_slave_count=1`: +**Example 2**: Enforcing a weak semi-sync replica toplogy, with `rpl_semi_sync_master_wait_for_slave_count=1`: ``` "DetectSemiSyncEnforcedQuery": "select 2586", @@ -123,7 +123,7 @@ and disable semi-sync on replica2. "RecoverLockedSemiSyncMaster": true ``` -Assuming this topology: +Assuming this topology, ``` ,- replica1 (priority = 2586, promotion rule = prefer, rpl_semi_sync_slave_enabled = 0) @@ -132,4 +132,4 @@ Assuming this topology: ``` `orchestrator` would detect a [`LockedSemiSyncMaster`](failure-detection.md#lockedsemisyncmaster) scenario -and enable semi-sync on replica1. +and enable semi-sync on replica1 (more preferable promotion rule). diff --git a/docs/failure-detection.md b/docs/failure-detection.md index 19d36f8ca..2cca6cdea 100644 --- a/docs/failure-detection.md +++ b/docs/failure-detection.md @@ -104,7 +104,7 @@ This scenario can happen when the master is overloaded. Clients would see a "Too 3. `rpl_semi_sync_master_timeout` is high enough such that master locks writes and does not fall back to asynchronous replication This condition only triggers after `ReasonableLockedSemiSyncMasterSeconds` has passed. If `ReasonableLockedSemiSyncMasterSeconds` is not set, -it trigger after `ReasonableReplicationLagSeconds`. +it triggers after `ReasonableReplicationLagSeconds`. Remediation of this condition can be to disable semi-sync on the master, or to bring up (or enable) sufficient semi-sync replicas.