vitessio · frouioui · Jul 27, 2023 · Jul 26, 2023 · Jul 27, 2023 · Jul 27, 2023
@@ -6,6 +6,7 @@
 - **[Known Issues](#known-issues)**
   - [MySQL & Xtrabackup known issue](#mysql-xtrabackup-ddl)
   - [VTTablet Restore Metrics](#vttablet-restore-metrics)
+  - [Schema-initialization stuck on semi-sync ACKs while upgrading to v16.0.0](#schema-init-upgrade)
 - **[Major Changes](#major-changes)**
   - **[Breaking Changes](#breaking-changes)**
     - [VTGate Advertised MySQL Version](#advertised-mysql-version)
@@ -101,11 +102,21 @@ or
 > ALTER TABLE your_table ENGINE=InnoDB;
 ```
 
-#### <a id="vttablet-restore-metrics">VTTablet Restore Metrics
+### <a id="vttablet-restore-metrics">VTTablet Restore Metrics
 
 As part of the VTTablet Sidecar Schema Maintenance Refactor in v16.0.0, we dropped the `local_metadata` table from the sidecar database schema. This table was storing a couple of metrics related to restores from backup, which have now been lost.
 They have been re-introduced in v17.0.0 as metrics that can be accessed from `/debug/vars`.
 
+### <a id="schema-init-upgrade"/>Schema-initialization stuck on semi-sync ACKs while upgrading to `v16.0.0`
+
+During upgrades from `v15.x.x` to `v16.0.0`, as part of `PromoteReplica` call, the schema-init realizes that there are schema diffs to apply and ends up writing to the database.
+The issue is that if semi-sync is enabled, all of these writes get blocked indefinitely.
+Eventually, `PromoteReplica` fails, and this fails the entire PRS call.
+
+A fix for this issue was merged on `release-16.0` in [PR#13441](https://github.com/vitessio/vitess/pull/13441), read the [corresponding bug report to learn more](https://github.com/vitessio/vitess/issues/13426).
+
+This issue will be addressed in the `v16.0.3` patch release.
+
 ## <a id="major-changes"/>Major Changes
 
 ### <a id="breaking-changes"/>Breaking Changes

@@ -3,7 +3,9 @@
 ### Table of Contents
 
 - **[Known Issues](#known-issues)**
-  - [MySQL & Xtrabackup known issue](#mysql-xtrabackup-ddl) 
+  - [MySQL & Xtrabackup known issue](#mysql-xtrabackup-ddl)
+  - [VTTablet Restore Metrics](#vttablet-restore-metrics)
+  - [Schema-initialization stuck on semi-sync ACKs while upgrading to v16.0.0](#schema-init-upgrade)
 - **[Major Changes](#major-changes)**
   - **[Breaking Changes](#breaking-changes)**
     - [VTGate Advertised MySQL Version](#advertised-mysql-version)
@@ -99,6 +101,21 @@ or
 > ALTER TABLE your_table ENGINE=InnoDB;
 ```
 
+### <a id="vttablet-restore-metrics">VTTablet Restore Metrics
+
+As part of the VTTablet Sidecar Schema Maintenance Refactor in v16.0.0, we dropped the `local_metadata` table from the sidecar database schema. This table was storing a couple of metrics related to restores from backup, which have now been lost.
+They have been re-introduced in v17.0.0 as metrics that can be accessed from `/debug/vars`.
+
+### <a id="schema-init-upgrade"/>Schema-initialization stuck on semi-sync ACKs while upgrading to `v16.0.0`
+
+During upgrades from `v15.x.x` to `v16.0.0`, as part of `PromoteReplica` call, the schema-init realizes that there are schema diffs to apply and ends up writing to the database.
+The issue is that if semi-sync is enabled, all of these writes get blocked indefinitely.
+Eventually, `PromoteReplica` fails, and this fails the entire PRS call.
+
+A fix for this issue was merged on `release-16.0` in [PR#13441](https://github.com/vitessio/vitess/pull/13441), read the [corresponding bug report to learn more](https://github.com/vitessio/vitess/issues/13426).
+
+This issue will be addressed in the `v16.0.3` patch release.
+
 ## <a id="major-changes"/>Major Changes
 
 ### <a id="breaking-changes"/>Breaking Changes

@@ -1,5 +1,18 @@
 # Release of Vitess v16.0.1
-## Summary
+
+## Known Issues
+
+### Schema-initialization stuck on semi-sync ACKs while upgrading to `v16.0.1`
+
+During upgrades from `v15.x.x` to `v16.0.1`, as part of `PromoteReplica` call, the schema-init realizes that there are schema diffs to apply and ends up writing to the database.
+The issue is that if semi-sync is enabled, all of these writes get blocked indefinitely.
+Eventually, `PromoteReplica` fails, and this fails the entire PRS call.
+
+A fix for this issue was merged on `release-16.0` in [PR#13441](https://github.com/vitessio/vitess/pull/13441), read the [corresponding bug report to learn more](https://github.com/vitessio/vitess/issues/13426).
+
+This issue will be addressed in the `v16.0.3` patch release.
+
+## Major Changes
 
 ### Upgrade to `go1.20.2`
 
@@ -8,6 +21,11 @@ Below is a summary of this Go patch release. You can learn more [here](https://g
 
 > go1.20.2 (released 2023-03-07) includes a security fix to the crypto/elliptic package, as well as bug fixes to the compiler, the covdata command, the linker, the runtime, and the crypto/ecdh, crypto/rsa, crypto/x509, os, and syscall packages.
 
+### Keyspace name validation in TopoServer
+
+Prior to v16.0.1, it was possible to create a keyspace with invalid characters, which would then be inaccessible to various cluster management operations.
+
+Keyspace names may no longer contain the forward slash ("/") character, and TopoServer's `GetKeyspace` and `CreateKeyspace` methods return an error if given such a name.
 
 ------------
 The entire changelog for this release can be found [here](https://github.com/vitessio/vitess/blob/main/changelog/16.0/16.0.1/changelog.md).

@@ -1,4 +1,16 @@
-## Summary
+## Known Issues
+
+### Schema-initialization stuck on semi-sync ACKs while upgrading to `v16.0.1`
+
+During upgrades from `v15.x.x` to `v16.0.1`, as part of `PromoteReplica` call, the schema-init realizes that there are schema diffs to apply and ends up writing to the database.
+The issue is that if semi-sync is enabled, all of these writes get blocked indefinitely.
+Eventually, `PromoteReplica` fails, and this fails the entire PRS call.
+
+A fix for this issue was merged on `release-16.0` in [PR#13441](https://github.com/vitessio/vitess/pull/13441), read the [corresponding bug report to learn more](https://github.com/vitessio/vitess/issues/13426).
+
+This issue will be addressed in the `v16.0.3` patch release.
+
+## Major Changes
 
 ### Upgrade to `go1.20.2`
 
@@ -11,5 +23,5 @@ Below is a summary of this Go patch release. You can learn more [here](https://g
 
 Prior to v16.0.1, it was possible to create a keyspace with invalid characters, which would then be inaccessible to various cluster management operations.
 
- Keyspace names may no longer contain the forward slash ("/") character, and TopoServer's `GetKeyspace` and `CreateKeyspace` methods return an error if given such a name.
+Keyspace names may no longer contain the forward slash ("/") character, and TopoServer's `GetKeyspace` and `CreateKeyspace` methods return an error if given such a name.
 
@@ -1,5 +1,18 @@
 # Release of Vitess v16.0.2
-## Summary
+
+## Known Issues
+
+### Schema-initialization stuck on semi-sync ACKs while upgrading to `v16.0.2`
+
+During upgrades from `v15.x.x` to `v16.0.2`, as part of `PromoteReplica` call, the schema-init realizes that there are schema diffs to apply and ends up writing to the database.
+The issue is that if semi-sync is enabled, all of these writes get blocked indefinitely.
+Eventually, `PromoteReplica` fails, and this fails the entire PRS call.
+
+A fix for this issue was merged on `release-16.0` in [PR#13441](https://github.com/vitessio/vitess/pull/13441), read the [corresponding bug report to learn more](https://github.com/vitessio/vitess/issues/13426).
+
+This issue will be addressed in the `v16.0.3` patch release.
+
+## Major Changes
 
 ### Upgrade to `go1.20.3`
 
@@ -11,7 +24,7 @@ Below is a summary of this Go patch release. You can learn more [here](https://g
 ### EffectiveCallerId in Vtgate gRPC calls
 
 A new flag `grpc-use-static-authentication-callerid` is added to gate the behavior introduced in https://github.com/vitessio/vitess/pull/12050.
-Earlier, we used to automatically set immediateCallerID to user from static authentication context that overrode the EffectiveCallerId. 
+Earlier, we used to automatically set immediateCallerID to user from static authentication context that overrode the EffectiveCallerId.
 
 
 ### Shard name validation in TopoServer

@@ -1,4 +1,16 @@
-## Summary
+## Known Issues
+
+### Schema-initialization stuck on semi-sync ACKs while upgrading to `v16.0.2`
+
+During upgrades from `v15.x.x` to `v16.0.2`, as part of `PromoteReplica` call, the schema-init realizes that there are schema diffs to apply and ends up writing to the database.
+The issue is that if semi-sync is enabled, all of these writes get blocked indefinitely.
+Eventually, `PromoteReplica` fails, and this fails the entire PRS call.
+
+A fix for this issue was merged on `release-16.0` in [PR#13441](https://github.com/vitessio/vitess/pull/13441), read the [corresponding bug report to learn more](https://github.com/vitessio/vitess/issues/13426).
+
+This issue will be addressed in the `v16.0.3` patch release.
+
+## Major Changes
 
 ### Upgrade to `go1.20.3`
 

@@ -3,6 +3,8 @@
 
 ### Table of Contents
 
+- **[Known Issues](#known-issues)**
+  - [Schema-initialization stuck on semi-sync ACKs while upgrading to v17.0.0](#schema-init-upgrade)
 - **[Major Changes](#major-changes)**
   - **[Breaking Changes](#breaking-changes)**
     - [Default Local Cell Preference for TabletPicker](#tablet-picker-cell-preference)
@@ -39,6 +41,17 @@
     - [Deprecated `vtgr`](#deprecated-vtgr)
     - [Deprecated `k8stopo`](#deprecated-k8stopo)
 
+## <a id="known-issues"/>Known Issues
+### <a id="schema-init-upgrade"/>Schema-initialization stuck on semi-sync ACKs while upgrading to `v17.0.0`
+
+During upgrades from `v16.x.x` to `v17.0.0`, as part of `PromoteReplica` call, the schema-init realizes that there are schema diffs to apply and ends up writing to the database.
+The issue is that if semi-sync is enabled, all of these writes get blocked indefinitely.
+Eventually, `PromoteReplica` fails, and this fails the entire PRS call.
+
+A fix for this issue was merged on `release-17.0` in [PR#13441](https://github.com/vitessio/vitess/pull/13411), read the [corresponding bug report to learn more](https://github.com/vitessio/vitess/issues/13426).
+
+This issue will be addressed in the `v17.0.1` patch release.
+
 
 ## <a id="major-changes"/>Major Changes
 

@@ -2,6 +2,8 @@
 
 ### Table of Contents
 
+- **[Known Issues](#known-issues)**
+  - [Schema-initialization stuck on semi-sync ACKs while upgrading to v17.0.0](#schema-init-upgrade)
 - **[Major Changes](#major-changes)**
   - **[Breaking Changes](#breaking-changes)**
     - [Default Local Cell Preference for TabletPicker](#tablet-picker-cell-preference)
@@ -38,6 +40,18 @@
     - [Deprecated `k8stopo`](#deprecated-k8stopo)
 
 
+## <a id="known-issues"/>Known Issues
+### <a id="schema-init-upgrade"/>Schema-initialization stuck on semi-sync ACKs while upgrading to `v17.0.0`
+
+During upgrades from `v16.x.x` to `v17.0.0`, as part of `PromoteReplica` call, the schema-init realizes that there are schema diffs to apply and ends up writing to the database.
+The issue is that if semi-sync is enabled, all of these writes get blocked indefinitely.
+Eventually, `PromoteReplica` fails, and this fails the entire PRS call.
+
+A fix for this issue was merged on `release-17.0` in [PR#13441](https://github.com/vitessio/vitess/pull/13411), read the [corresponding bug report to learn more](https://github.com/vitessio/vitess/issues/13426).
+
+This issue will be addressed in the `v17.0.1` patch release.
+
+
 ## <a id="major-changes"/>Major Changes
 
 ### <a id="breaking-changes"/>Breaking Changes