Some more insights about this issue... It happens every time (on different users) on quota lookup for all users:

$ doveadm quota get -A > /dev/null; echo $? doveadm(demo@example.com): Error: auth-master: userdb list: User listing returned failure doveadm: Error: cmd quota get: Failed to iterate through some users 75

Full debug output see [1].

In mail.log, I then find this line:

dovecot: auth: Error: auth-worker: Aborted LIST request for *: Shutting down

The weird thing is that this problem happens always one one server (2200 users), while never happening on another (1200 users). Both running 100% same configuration / same versions (Dovecot 2.4.2 / Debian Bookworm, Percona for MySQL 8.4.7), and both now with disabled IMAPSieve Plugin (imap-sieve) which is broken in 2.4.2. Above problem occurs both with or without doveadm_worker_count = 4, so that's not the culprit. The whole doveadm quota get -A always runs in less than 3s, so I cannot imagine any MySQL connection issues with the iterate_query.

I did not override anything in service auth or service auth-worker sections.

Any recommendations?

Thanks, Philip

[1] $ doveadm -Dv quota get -A 2>&1 | tee /tmp/debug.log (...) Feb 26 13:06:17 doveadm(demo@example.com)<358389><>: Debug: auth-master: userdb lookup(demo@example.com): Started userdb lookup Feb 26 13:06:17 doveadm(demo@example.com)<358389><>: Debug: auth-master: request [4211869176]: Created Feb 26 13:06:17 doveadm(demo@example.com)<358389><>: Debug: auth-master: userdb lookup(demo@example.com): request [4211869176]: Waiting for request to complete Feb 26 13:06:17 doveadm(demo@example.com)<358389><>: Debug: auth-master: conn unix:/run/dovecot/auth-userdb (pid=353974,uid=0): Sending requests Feb 26 13:06:17 doveadm(demo@example.com)<358389><>: Debug: auth-master: userdb lookup(demo@example.com): request [4211869176]: Sent Feb 26 13:06:17 doveadm(demo@example.com)<358389><>: Debug: auth-master: conn unix:/run/dovecot/auth-userdb (pid=353974,uid=0): auth input: USER 4211869176 demo@example.com home=/var/vmail/example.com/demo uid=998 gid=998 quota_storage_size=300M Feb 26 13:06:17 doveadm(demo@example.com)<358389><>: Debug: auth-master: userdb lookup(demo@example.com): request [4211869176]: Got reply: USER demo@example.com home=/var/vmail/example.com/demo uid=998 gid=998 quota_storage_size=300M Feb 26 13:06:17 doveadm(demo@example.com)<358389><>: Debug: auth-master: userdb lookup(demo@example.com): auth USER input: demo@example.com home=/var/vmail/example.com/demo uid=998 gid=998 quota_storage_size=300M Feb 26 13:06:17 doveadm(demo@example.com)<358389><>: Debug: auth-master: userdb lookup(demo@example.com): Finished userdb lookup (username=demo@example.com home=/var/vmail/example.com/demo uid=998 gid=998 quota_storage_size=300M) Feb 26 13:06:17 doveadm(demo@example.com)<358389><>: Debug: auth-master: userdb lookup(demo@example.com): request [4211869176]: Remove Feb 26 13:06:17 doveadm(demo@example.com)<358389><>: Debug: auth-master: userdb lookup(demo@example.com): request [4211869176]: Finished waiting for request Feb 26 13:06:17 doveadm(demo@example.com)<358389><>: Debug: auth-master: userdb lookup(demo@example.com): request [4211869176]: Destroy Feb 26 13:06:17 doveadm(demo@example.com)<358389><>: Debug: Added setting via userdb: quota_storage_size=300M Feb 26 13:06:17 doveadm(demo@example.com): Debug: Effective uid=998, gid=998, home=/var/vmail/example.com/demo Feb 26 13:06:17 doveadm(demo@example.com): Debug: acl: Shared mailbox listing disabled: dict { .. } named list filter is missing Feb 26 13:06:17 doveadm(demo@example.com): Debug: Namespace inbox: type=private, prefix=INBOX/, sep=/, inbox=yes, hidden=no, list=yes, subscriptions=yes Feb 26 13:06:17 doveadm(demo@example.com): Debug: fs: root=/var/vmail/example.com/demo/sdbox, index=, indexpvt=, control=, inbox=, alt= Feb 26 13:06:17 doveadm(demo@example.com): Debug: acl: initializing backend vfile Feb 26 13:06:17 doveadm(demo@example.com): Debug: acl: acl username = demo@example.com Feb 26 13:06:17 doveadm(demo@example.com): Debug: acl: owner = yes Feb 26 13:06:17 doveadm(demo@example.com): Debug: acl: ignore = no Feb 26 13:06:17 doveadm(demo@example.com): Debug: acl: vfile: Deprecated Global ACL file: /etc/dovecot/dovecot-acl Feb 26 13:06:17 doveadm(demo@example.com): Debug: Namespace : type=private, prefix=, sep=, inbox=no, hidden=yes, list=no, subscriptions=no Feb 26 13:06:17 doveadm(demo@example.com): Debug: none: root=/var/vmail/example.com/demo/sdbox, index=, indexpvt=, control=, inbox=, alt= Feb 26 13:06:17 doveadm(demo@example.com): Debug: quota-count: quota_over_status check: quota_over_mask unset - skipping Feb 26 13:06:17 doveadm(demo@example.com): Debug: Mailbox INBOX: Mailbox opened Feb 26 13:06:17 doveadm(demo@example.com): Debug: User session is finished Feb 26 13:06:17 doveadm(demo@example.com): Debug: auth-master: conn unix:/run/dovecot/auth-userdb (pid=353974,uid=0): auth input: DONE 2802712577 fail Feb 26 13:06:17 doveadm(demo@example.com): Debug: auth-master: userdb list: request [2802712577]: Got reply: DONE fail Feb 26 13:06:17 doveadm(demo@example.com): Error: auth-master: userdb list: User listing returned failure Feb 26 13:06:17 doveadm(demo@example.com): Debug: auth-master: userdb list: request [2802712577]: Remove Feb 26 13:06:17 doveadm(demo@example.com): Debug: auth-master: userdb list: request [2802712577]: Destroy Feb 26 13:06:17 doveadm(demo@example.com): Debug: auth-master: userdb list: Listing users failed Feb 26 13:06:17 doveadm(demo@example.com): Debug: auth-master: conn unix:/run/dovecot/auth-userdb (pid=353974,uid=0): Disconnected: Connection closed (fd=9) Feb 26 13:06:17 doveadm(demo@example.com): Debug: auth-master: conn unix:/run/dovecot/auth-userdb (pid=353974,uid=0): Disconnected from auth service Feb 26 13:06:17 doveadm: Error: cmd quota get: Failed to iterate through some users Feb 26 13:06:17 doveadm: Debug: auth-master: conn unix:/run/dovecot/auth-userdb (pid=353974,uid=0): Disconnected: Connection closed (fd=10) Feb 26 13:06:17 doveadm: Debug: auth-master: conn unix:/run/dovecot/auth-userdb (pid=353974,uid=0): Disconnected from auth service

On 25 Feb 2026, at 15:48, Philip Iezzi via dovecot <dovecot@dovecot.org> wrote:

Hi there

On a Dovecot 2.4.2 (Debian Bookworm) server with over 1300 users, I am using the following config to retrieve quota usage information with doveadm:

---

quota "User quota" { }

mail_plugins = quota acl mail_log notify

userdb sql { iterate_query = SELECT username AS user, CONCAT(quota, 'M') AS quota_storage_size FROM mailaccounts WHERE active = 1

query =
SELECT '/var/vmail/%{user | domain}/%{user | username}' AS home, 'vmail' AS uid, 'vmail' AS gid, CONCAT(quota, 'M') AS quota_storage_size
FROM mailaccounts
WHERE username = '%{user}' AND (active = 1 OR transport_suspended = 0) }

---

Initially, I had to run doveadm quota recalc -A to recalc quotas and populate the count quota driver which is enabled by default for "User quota". But still, it took roughly 20ms per single user or 15-20s for all users:

$ time doveadm -f tab quota get -u demo@example.com real 0m0.020s $ time doveadm -f tab quota get -A real 0m16.800s

Now, to greatly speed this up, I have introduced parallel processing:

doveadm_worker_count = 4

Like this, doveadm -f tab quota get -A runs approx 10x faster, done in 1.5 - 2.5s But there is one major drawback which I assume to be a bug:

sane output without doveadm_worker_count = 4 => always 6 fields

demo@example.com User quota STORAGE 29 204800 0 demo@example.com User quota MESSAGE 1 - 0

broken output with doveadm_worker_count = 4 => sometimes 7 fields

demo@example.com User quota STORAGE 29 2048 00 0 demo@example.com User quota MESSAGE 1 - 0

Somehow, the tab formatter does not play nicely together with parallel processing. On some output, the value gets split apart by an extra tab, e.g. '2024<TAB>00' in above example. Can you explain this corrupted data? Some kind of "output interleaving" seems to happen when running parallel workers. If I switch to json output (doveadm -f json quota get -A), this does not seem to happen and I always get valid JSON output, even with doveadm_worker_count = 4.

Cheers, Philip

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