From b2f8253ba856a96e475afa80f2be21fcd9bfd836 Mon Sep 17 00:00:00 2001 From: Venkatraju V Date: Wed, 28 Aug 2024 16:58:49 -0700 Subject: [PATCH] add release notes Signed-off-by: Venkatraju V --- changelog/21.0/21.0.0/summary.md | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/changelog/21.0/21.0.0/summary.md b/changelog/21.0/21.0.0/summary.md index f24b2ee87ab..d5fefd74f0c 100644 --- a/changelog/21.0/21.0.0/summary.md +++ b/changelog/21.0/21.0.0/summary.md @@ -13,6 +13,7 @@ - **[Tablet Throttler: Multi-Metric support](#tablet-throttler)** - **[Allow Cross Cell Promotion in PRS](#allow-cross-cell)** - **[Support for recursive CTEs](#recursive-cte)** + - **[VTGate Tablet Balancer](#tablet-balancer)** ## Major Changes @@ -105,4 +106,11 @@ Up until now if the users wanted to promote a replica in a different cell than t We have now added a new flag `--allow-cross-cell-promotion` that lets `PlannedReparentShard` choose a primary in a different cell even if no new primary is provided explicitly. ### Experimental support for recursive CTEs -We have added experimental support for recursive CTEs in Vitess. We are marking it as experimental because it is not yet fully tested and may have some limitations. We are looking for feedback from the community to improve this feature. \ No newline at end of file +We have added experimental support for recursive CTEs in Vitess. We are marking it as experimental because it is not yet fully tested and may have some limitations. We are looking for feedback from the community to improve this feature. + +### VTGate Tablet Balancer +When a VTGate routes a query and has multiple available tablets for a given shard / tablet type (e.g. REPLICA), the current default behavior routes the query with local cell affinity and round robin policy. The VTGate Tablet Balancer provides an alternate mechanism that routes queries to maintain an even distribution of query load to each tablet, while preferentially routing to tablets in the same cell as the VTGate. + +The tablet balancer is enabled by a new flag `--enable-balancer` and configured by `--balancer-vtgate-cells` and `--balancer-keyspaces`. + +See [RFC for details](https://github.com/vitessio/vitess/issues/12241). \ No newline at end of file