SUMMARY

Because the autocomplete of email addresses from my address book stopped working in kmail, I removed and re-added the corresponding carddav resource. That fixed the autocompletion issue. However, in the logs I saw an error that may be of interest, as it may indicate wrong assumptions implicit in the code that may make using the SQLite backend (as I do) less robust.


OBSERVED RESULT

jan 07 09:41:07 sysoppad akonadiserver[27986]: org.kde.pim.akonadiserver: Error while handling command FetchItems on connection akonadi_davgroupware_resource_25 (0x556ecda28f30)
jan 07 09:41:12 sysoppad akonadiserver[27986]: org.kde.pim.akonadiserver: DATABASE ERROR while PREPARING QUERY:
jan 07 09:41:12 sysoppad akonadiserver[27986]: org.kde.pim.akonadiserver:   Error code: "1"
jan 07 09:41:12 sysoppad akonadiserver[27986]: org.kde.pim.akonadiserver:   DB error:  "too many SQL variables"
jan 07 09:41:12 sysoppad akonadiserver[27986]: org.kde.pim.akonadiserver:   Error text: "too many SQL variables Unable to execute statement"
jan 07 09:41:12 sysoppad akonadiserver[27986]: org.kde.pim.akonadiserver:   Query: "SELECT PimItemTable.id, PimItemTable.rev, PimItemTable.remoteId, PimItemTable.remoteRevision, PimItemTable.gid, PimItemTable.collectionId, PimItemTable.mimeTypeId, PimItemTable.datetime, PimItemTable.atime, PimItemTable.dirty, PimItemTable.size FROM PimItemTable INNER JOIN CollectionTable ON ( PimItemTable.collectionId = CollectionTable.id ) WHERE ( PimItemTable.remoteId IN ( :0, :1, :2, :3, :4, :5, :6, :7, :8, :9, :10, :11, :12, :13, :14, :15, :16, :17, :18, :19, :20, :21, :22, :23, :24, :25, :26, :27, :28, :29, :30, :31, :32, :33, :34, :35, :36, :37, :38, :39, :40, :41, :42, :43, :44, :45, :46, :47, :48, :49, :50, :51, :52, :53, :54, :55, :56, :57, :58, :59, :60, :61, :62, :63, :64, :65, :66, :67, :68, :69, :70, :71, :72, :73, :74, :75, :76, :77, :78, :79, :80, :81, :82, :83, :84, :85, :86, :87, :88, :89, :90, :91, :92, :93, :94, :95, :96, :97, :98, :99, :100, :101, :102, :103, :104, :105, :106, :107, :108, :109, :110, :111, :112, :113, :114, :115, :116, :117, :118, :119, :120, :121, :122, :123, :124, :125, :126, :127, :128, :129, :130, :131, :132, :133, :134, :135, :136, :137, :138, :139, :140, :141, :142, :143, :144, :145, :146, :147, :148, :149, :150, :151, :152, :153, :154, :155, :156, :157, :158, :159, :160, :161, :162, :163, :164, :165, :166, :167, :168, :169, :170, :171, :172, :173, :174, :175, :176, :177, :178, :179, :180, :181, :182, :183, :184, :185, :186, :187, :188, :189, :190, :191, :192, :193, :194, :195, :196, :197, :198, :199, :200, :201, :202, :203, :204, :205, :206, :207, :208, :209, :210, :211, :212, :213, :214, :215, :216, :217, :218, :219, :220, :221, :222, :223, :224, :225, :226, :227, :228, :229, :230, :231, :232, :233, :234, :235, :236, :237, :238, :239, :240, :241, :242, :243, :244, :245, :246, :247, :248, :249, :250, :251, :252, :253, :254, :255, :256, :257, :258, :259, :260, :261, :262, :263, :264, :265, :266, :267, :268, :269, :270, :271, :272, :273, 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CollectionTable.resourceId = :1230 )"
jan 07 09:41:12 sysoppad akonadi_birthdays_resource[27996]: org.kde.pim.akonadicore: Deleting items from the akonadi database failed: "Unable to execute query"


EXPECTED RESULT

No error


SOFTWARE/OS VERSIONS
KDE Apps: 19.08.4
KDE Plasma Version: 5.17.4
KDE Frameworks Version: 5.64.0
Qt Version: 5.13.2