This is mostly based on forest's notes and this script.

Purge Remote Media

• get a timestamp in unix seconds: date +%s000 --date "10 days ago"
  • everything before this date will be purged
• curl -k -X POST "http://localhost:8008/_synapse/admin/v1/purge_media_cache?before_ts=$your-timestamp-here&access_token=$your-access-token"

Purge Big Rooms

• use some forest scripts

Purge Rooms from Database

• get a list of the biggest rooms
  • docker compose exec postgresql psql -U synapse -d synapse -c "select room_id, count(*) from state_groups_state group by room_id order by count(*) DESC LIMIT 100"
  • run this inside the synapse directory
  • copy biggest rooms to a text file somewhere
• use this kick-user-purge-room script for each room id (must be wrapped in single quotes)

#!/bin/bash

roomid="$1"
accesstoken="insert-matrix-access-token-here"

[ -z "$roomid" ] && exit 1

echo "getting list of users in $roomid..."                                                                             

curl -sS "localhost:8008/_synapse/admin/v1/rooms/$roomid/members?access_token=$accesstoken" | jq -r '.members[]' | grep 'your-matrix-server-domain.com'


echo "deleting $roomid..."                                                                                             

curl -H "Content-Type: application/json" -X DELETE "localhost:8008/_synapse/admin/v2/rooms/$roomid?access_token=$accesstoken" \
        --data '{ "block": false, "force_purge": true, "purge": true, "message": "This room is being cleaned, stand by..." }'

echo '' 
echo 'GET /_synapse/admin/v2/rooms/$roomid/delete_status : '                                                           

curl -sS "localhost:8008/_synapse/admin/v2/rooms/$roomid/delete_status?access_token=$accesstoken"

– ./kick-user-purge-room '!some-room-id'

Purge State Group IDs

• Get all the state group ids from the deleted rooms
  • docker compose exec postgresql psql -U synapse -d synapse -c " SELECT id from state_groups where room_id = '"'!'"some-room-id' OR room_id = '"'!'"some-room-id'; " > stategroups1.txt
  • docker compose exec postgresql psql -U synapse -d synapse -c " SELECT id from state_groups where room_id = '"'!'"some-room-id' OR room_id = '"'!'"some-room-id'; " > stategroups2.txt
• remove header and footer from the stategroups files with a text editor
• sort the state group ids and convert them to postgres delete statements
  • cat ./stategroups1.txt | sort | sed -E 's/([0-9]+)/DELETE FROM state_groups_state where state_group = \1;/' > stategroups1.sql
  • cat ./stategroups2.txt | sort | sed -E 's/([0-9]+)/DELETE FROM state_groups_state where state_group = \1;/' > stategroups2.sql
• move the files into the docker container sudo cp ./stategroups{1,2}.sql ./postgresdata/
• delete the state group state!
  • docker compose exec postgresql psql -U synapse -d synapse -f /var/lib/postgresql/data/stategroups1.sql
  • docker compose exec postgresql psql -U synapse -d synapse -f /var/lib/postgresql/data/stategroups2.sql

Cleanup

• delete from other state group related tables
  • docker compose exec postgresql psql -U synapse -d synapse -c "DELETE FROM state_group_edges where state_group in (SELECT id from state_groups where room_id = '"'!'"some-room-id'); "
  • docker compose exec postgresql psql -U synapse -d synapse -c "DELETE FROM event_to_state_groups where state_group in (SELECT id from state_groups where room_id = '"'!'"some-room-id'); "
  • docker compose exec postgresql psql -U synapse -d synapse -c "DELETE FROM state_groups where room_id = '"'!'"some-room-id'; "

Remove table and index bloat

• commands from this excellent article on cleaning up synapse bloat
  • I didn't use the rust compressor tool because I used forest's notes to delete the state of the massive rooms instead
• reindex the synapse database
  • docker compose exec postgresql psql -U synapse -d synapse -c "REINDEX (VERBOSE) DATABASE synapse";
• vaccum up the table bloat
  • docker compose exec postgresql psql -U synapse -d synapse -c "VACUUM FULL VERBOSE";

DONE!