Merge remote-tracking branch 'origin/release-v1.21.2' into bbz/info-mainline-1.21.2 github/bbz/info-mainline-1.21.2 bbz/info-mainline-1.21.2

1 files changed, 11 insertions, 0 deletions

diff --git a/docs/postgres.md b/docs/postgres.md

index e71a1975d8..c30cc1fd8c 100644
--- a/docs/postgres.md
+++ b/docs/postgres.md
@@ -106,6 +106,17 @@ Note that the above may fail with an error about duplicate rows if corruption
 has already occurred, and such duplicate rows will need to be manually removed.
 
 
+## Fixing inconsistent sequences error
+
+Synapse uses Postgres sequences to generate IDs for various tables. A sequence
+and associated table can get out of sync if, for example, Synapse has been
+downgraded and then upgraded again.
+
+To fix the issue shut down Synapse (including any and all workers) and run the
+SQL command included in the error message. Once done Synapse should start
+successfully.
+
+
 ## Tuning Postgres
 
 The default settings should be fine for most deployments. For larger