Akonadi keeps downloading the same emails over and over again for all folders, since it does not update the UIDNEXT entries in the collectionattributetable table. STEPS TO REPRODUCE 1. Add an IMAP account, on a server with UIDNEXT support 2. Synchronise 3. Receiver more emails 4. Synchronise 5. Synchronise again OBSERVED RESULT Step 5 downloads the emails that Step 4 had already downloaded. The UIDNEXT entry in the database remains as it was, no update. EXPECTED RESULT Emails that have been downloaded are not downloaded again. SOFTWARE/OS VERSIONS Linux/KDE Plasma: (available in About System) KDE Plasma Version: 5.15.3 KDE Frameworks Version: 5.56.0 Qt Version: 5.12.2 ADDITIONAL INFORMATION From the logs: akonadi_imap_resource[27122]: org.kde.pim.imapresource.trace: starting: RetrieveItemsTask akonadi_imap_resource[27122]: org.kde.pim.imapresource: Starting retrieval for "INBOX" akonadi_imap_resource[27122]: org.kde.pim.imapresource: Starting message retrieval. Elapsed(ms): 235 akonadi_imap_resource[27122]: org.kde.pim.imapresource: UidValidity: 1231428926 Local UidValidity: 1231428926 akonadi_imap_resource[27122]: org.kde.pim.imapresource: MessageCount: 1131 Local message count: 1131 akonadi_imap_resource[27122]: org.kde.pim.imapresource: UidNext: 21432 Local UidNext: 21428 akonadi_imap_resource[27122]: org.kde.pim.imapresource: HighestModSeq: 3639 Local HighestModSeq: 3623 akonadi_imap_resource[27122]: org.kde.pim.imapresource: Fetching new messages: UidNext: 21432 Old UidNext: 21428 akonadi_imap_resource[27122]: org.kde.pim.akonadiagentbase: 1131 akonadi_imap_resource[27122]: org.kde.pim.akonadicore: 1131 akonadi_imap_resource[27122]: org.kde.pim.imapresource: Fetching 2 intervals akonadi_imap_resource[27122]: org.kde.pim.akonadicore: Received: 2 In total: 2 Wanted: 1131 akonadi_imap_resource[27122]: org.kde.pim.akonadicore: Received: 1 In total: 3 Wanted: 1131 akonadi_imap_resource[27122]: org.kde.pim.imapresource: Listing flags 1 21427 akonadi_imap_resource[27122]: org.kde.pim.imapresource: Starting flag retrieval. Elapsed(ms): 670 akonadi_imap_resource[27122]: org.kde.pim.imapresource: Fetching 211 intervals akonadi_imap_resource[27122]: org.kde.pim.akonadicore: Received: 525 In total: 528 Wanted: 1131 akonadi_imap_resource[27122]: org.kde.pim.akonadicore: Received: 475 In total: 1003 Wanted: 1131 akonadi_imap_resource[27122]: org.kde.pim.imapresource: Fetching 24 intervals akonadi_imap_resource[27122]: org.kde.pim.akonadicore: Received: 102 In total: 1105 Wanted: 1131 akonadi_imap_resource[27122]: org.kde.pim.akonadicore: Received: 26 In total: 1131 Wanted: 1131 akonadi_imap_resource[27122]: org.kde.pim.imapresource: Applying collection changes akonadi_imap_resource[27122]: org.kde.pim.imapresource: Retrieval complete. Elapsed(ms): 2562 akonadi_imap_resource[27122]: org.kde.pim.akonadicore: ItemSync of collection 15 finished akonadi_imap_resource[27122]: org.kde.pim.imapresource.trace: RetrieveCollectionMetadataTask akonadi_imap_resource[27122]: org.kde.pim.imapresource.trace: starting: RetrieveCollectionMetadataTask akonadi_imap_resource[27122]: org.kde.pim.imapresource: ".INBOX" akonadi_imap_resource[27122]: org.kde.pim.akonadiagentbase: 15 "Inbox" akonadi_imap_resource[27122]: org.kde.pim.imapresource.trace: RetrieveItemsTask akonadi_imap_resource[27122]: org.kde.pim.imapresource.trace: starting: RetrieveItemsTask akonadi_imap_resource[27122]: org.kde.pim.imapresource: Starting retrieval for "INBOX" akonadi_imap_resource[27122]: org.kde.pim.imapresource: Starting message retrieval. Elapsed(ms): 149 akonadi_imap_resource[27122]: org.kde.pim.imapresource: UidValidity: 1231428926 Local UidValidity: 1231428926 akonadi_imap_resource[27122]: org.kde.pim.imapresource: MessageCount: 1131 Local message count: 1131 akonadi_imap_resource[27122]: org.kde.pim.imapresource: UidNext: 21432 Local UidNext: 21428 akonadi_imap_resource[27122]: org.kde.pim.imapresource: HighestModSeq: 3639 Local HighestModSeq: 3623 akonadi_imap_resource[27122]: org.kde.pim.imapresource: Fetching new messages: UidNext: 21432 Old UidNext: 21428 akonadi_imap_resource[27122]: org.kde.pim.akonadiagentbase: 1131 akonadi_imap_resource[27122]: org.kde.pim.akonadicore: 1131 akonadi_imap_resource[27122]: org.kde.pim.imapresource: Fetching 2 intervals akonadi_imap_resource[27122]: org.kde.pim.akonadicore: Received: 2 In total: 2 Wanted: 1131 akonadi_imap_resource[27122]: org.kde.pim.akonadicore: Received: 1 In total: 3 Wanted: 1131 akonadi_imap_resource[27122]: org.kde.pim.imapresource: Listing flags 1 21427 akonadi_imap_resource[27122]: org.kde.pim.imapresource: Starting flag retrieval. Elapsed(ms): 367 akonadi_imap_resource[27122]: org.kde.pim.imapresource: Fetching 211 intervals akonadi_imap_resource[27122]: org.kde.pim.akonadicore: Received: 525 In total: 528 Wanted: 1131 akonadi_imap_resource[27122]: org.kde.pim.akonadicore: Received: 475 In total: 1003 Wanted: 1131 akonadi_imap_resource[27122]: org.kde.pim.imapresource: Fetching 24 intervals akonadi_imap_resource[27122]: org.kde.pim.akonadicore: Received: 102 In total: 1105 Wanted: 1131 akonadi_imap_resource[27122]: org.kde.pim.akonadicore: Received: 26 In total: 1131 Wanted: 1131 akonadi_imap_resource[27122]: org.kde.pim.imapresource: Applying collection changes akonadi_imap_resource[27122]: org.kde.pim.imapresource: Retrieval complete. Elapsed(ms): 2275 akonadi_imap_resource[27122]: org.kde.pim.akonadicore: ItemSync of collection 15 finished As can be seen, akonadi downloaded the same emails twice. Note how the reported local UidNext in the second run is still the same as it was in the first run. I enabled query logging in MySQL and did not see any UPDATE statements affecting the CollectionAttributeTable. It does show: 363 Execute SELECT CollectionAttributeTable.id, CollectionAttributeTable.collectionId, CollectionAttributeTable.type, CollectionAttributeTable.value FROM CollectionAttributeTable WHERE ( collectionId = 15 AND type = 'uidnext' )
Possibly solved by https://mail.kde.org/pipermail/distributions/2019-April/000314.html. Attempting to test.
Confirmed, those patches fix the issue.