Transaction Deadlocks on SQL Server Insert with EF Core

Question

I'm trying to do a large number of individual inserts containing a large amount of data quickly using Entity Framework Core. I'm inserting data into several related tables and occasionally get a SqlException with the following message;

Transaction (Process ID 120) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.

The only reads I am doing is as part of the insert to retrieve the ID's for the newly created records. You can see the Entity Framework Core logs from the inserts taking place. If it makes a difference, I added a single non-clustered index to the UniqueId column.

How can I avoid deadlocks and get better performance as a result?

2018-06-13 17:11:59 DBG Executing DbCommand [Parameters=["@p0='40515' (Nullable = true), @p1='22a98afd-57c9-4821-8027-db9a7d1098d0' (Nullable = true), @p2='2017-12-13T17:11:41.8202539+01:00' (Nullable = true), @p3='2018-06-13T16:11:57.3627370+00:00', @p4='11' (Nullable = true), @p5='0' (Nullable = true), @p6='Teacher Tech' (Nullable = false) (Size = 1000), @p7='3' (Nullable = true), @p8='True' (Nullable = true), @p9='7f72ce12-7c3a-449e-b456-97db816dd7e6' (Nullable = true), @p10='11.0.40515.3' (Size = 50), @p11='False' (Nullable = true), @p12='False' (Nullable = true), @p13='bridge 2015-12-09_15-29 97f149c' (Size = 200), @p14='Global' (Nullable = false) (Size = 100), @p15='False' (Nullable = true), @p16='Development' (Nullable = false) (Size = 50), @p17='2018-06-13T16:11:57.3627551+00:00', @p18='Onyx' (Size = 200), @p19='Bridge_C67HD_AUDIO' (Size = 200), @p20='195.110.84.182' (Size = 50), @p21='72Mbps' (Size = 100), @p22='02:00:00:00:00:00' (Size = 50), @p23='bridgewifi' (Size = 100), @p24='Android' (Nullable = false) (Size = 1000), @p25='4.2.2' (Nullable = false) (Size = 200), @p26='10' (Nullable = true), @p27='EATT-2322' (Size = 200), @p28='751619276', @p29='1073741824', @p30='322122548', @p31='East African Standard Time' (Size = 50), @p32='536870912' (Nullable = true), @p33='10800' (Nullable = true), @p34='2' (Nullable = true), @p35='2018-06-13T16:11:41.8347079+01:00', @p36='2018-06-13T16:11:57.3627630+00:00', @p37='2018-06-13T16:11:57.3627630+00:00', @p38='0', @p39='2018-06-13T17:11:41.8356696+01:00', @p40='b2c398ca-43dd-49da-a89c-b5319756271d', @p41='1' (Nullable = true), @p42='[email protected]' (Size = 100), @p43='T00001' (Size = 20), @p44='2018-06-13T16:11:57.3627658+00:00', @p45='' (DbType = Int32), @p46='Teacher 1' (Size = 100)"], CommandType='Text', CommandTimeout='30']"
""SET NOCOUNT ON;
INSERT INTO [log].[App] ([BuildVersion], [DatabaseId], [Installed], [LastUpdated], [MajorVersion], [MinorVersion], [Name], [RevisionVersion], [TrainingMode], [UniqueId], [Version])
VALUES (@p0, @p1, @p2, @p3, @p4, @p5, @p6, @p7, @p8, @p9, @p10);
SELECT [AppId]
FROM [log].[App]
WHERE @@ROWCOUNT = 1 AND [AppId] = scope_identity();

INSERT INTO [log].[Device] ([AutoTime], [AutoTimeZone], [BuildNumber], [Country], [DeveloperMode], [Environment], [LastUpdated], [Manufacturer], [Model], [NetworkIpAddress], [NetworkLinkSpeed], [NetworkMacAddress], [NetworkSSID], [Platform], [PlatformVersion], [ScreenTimeout], [Serial], [StorageFree], [StorageTotal], [StorageUsed], [TimeZone], [TotalMemory], [UtcOffsetSeconds], [WifiSleepPolicy])
VALUES (@p11, @p12, @p13, @p14, @p15, @p16, @p17, @p18, @p19, @p20, @p21, @p22, @p23, @p24, @p25, @p26, @p27, @p28, @p29, @p30, @p31, @p32, @p33, @p34);
SELECT [DeviceId]
FROM [log].[Device]
WHERE @@ROWCOUNT = 1 AND [DeviceId] = scope_identity();

INSERT INTO [log].[Message] ([CreatedTimestamp], [LastUpdated], [ReceivedTimestamp], [Retries], [SentTimestamp], [UniqueId])
VALUES (@p35, @p36, @p37, @p38, @p39, @p40);
SELECT [MessageId]
FROM [log].[Message]
WHERE @@ROWCOUNT = 1 AND [MessageId] = scope_identity();

INSERT INTO [log].[User] ([BridgeUserId], [Email], [EmployeeId], [LastUpdated], [LogId], [Name])
VALUES (@p41, @p42, @p43, @p44, @p45, @p46);
SELECT [UserId]
FROM [log].[User]
WHERE @@ROWCOUNT = 1 AND [UserId] = scope_identity();"

2018-06-13 17:12:00 DBG Executing DbCommand [Parameters=["@p47='2' (Nullable = true), @p48='3454', @p49='3454', @p50='T90282' (Size = 20), @p51='3454', @p52='900' (Nullable = true), @p53='232' (Nullable = true), @p54='8', @p55='3454' (Nullable = true), @p56='2' (Nullable = true), @p57='3454', @p58='3454', @p59='T90282' (Size = 20), @p60='3454', @p61='900' (Nullable = true), @p62='232' (Nullable = true), @p63='8', @p64='3454' (Nullable = true), @p65='2' (Nullable = true), @p66='3454', @p67='3454', @p68='T90282' (Size = 20), @p69='3454', @p70='900' (Nullable = true), @p71='232' (Nullable = true), @p72='8', @p73='3454' (Nullable = true), @p74='2' (Nullable = true), @p75='3454', @p76='3454', @p77='T90282' (Size = 20), @p78='3454', @p79='900' (Nullable = true), @p80='232' (Nullable = true), @p81='8', @p82='3454' (Nullable = true), @p83='2' (Nullable = true), @p84='3454', @p85='3454', @p86='T90282' (Size = 20), @p87='3454', @p88='900' (Nullable = true), @p89='232' (Nullable = true), @p90='8', @p91='3454' (Nullable = true), @p92='2' (Nullable = true), @p93='3454', @p94='3454', @p95='T90282' (Size = 20), @p96='3454', @p97='900' (Nullable = true), @p98='232' (Nullable = true), @p99='8', @p100='3454' (Nullable = true), @p101='2' (Nullable = true), @p102='3454', @p103='3454', @p104='T90282' (Size = 20), @p105='3454', @p106='900' (Nullable = true), @p107='232' (Nullable = true), @p108='8', @p109='3454' (Nullable = true), @p110='2' (Nullable = true), @p111='3454', @p112='3454', @p113='T90282' (Size = 20), @p114='3454', @p115='900' (Nullable = true), @p116='232' (Nullable = true), @p117='8', @p118='3454' (Nullable = true), @p119='2' (Nullable = true), @p120='3454', @p121='3454', @p122='T90282' (Size = 20), @p123='3454', @p124='900' (Nullable = true), @p125='232' (Nullable = true), @p126='8', @p127='3454' (Nullable = true), @p128='2' (Nullable = true), @p129='3454', @p130='3454', @p131='T90282' (Size = 20), @p132='3454', @p133='900' (Nullable = true), @p134='232' (Nullable = true), @p135='8', @p136='3454' (Nullable = true), @p137='2' (Nullable = true), @p138='3454', @p139='3454', @p140='T90282' (Size = 20), @p141='3454', @p142='900' (Nullable = true), @p143='232' (Nullable = true), @p144='8', @p145='3454' (Nullable = true), @p146='2' (Nullable = true), @p147='3454', @p148='3454', @p149='T90282' (Size = 20), @p150='3454', @p151='900' (Nullable = true), @p152='232' (Nullable = true), @p153='8', @p154='3454' (Nullable = true), @p155='2' (Nullable = true), @p156='3454', @p157='3454', @p158='T90282' (Size = 20), @p159='3454', @p160='900' (Nullable = true), @p161='232' (Nullable = true), @p162='8', @p163='3454' (Nullable = true), @p164='2' (Nullable = true), @p165='3454', @p166='3454', @p167='T90282' (Size = 20), @p168='3454', @p169='900' (Nullable = true), @p170='232' (Nullable = true), @p171='8', @p172='3454' (Nullable = true), @p173='2' (Nullable = true), @p174='3454', @p175='3454', @p176='T90282' (Size = 20), @p177='3454', @p178='900' (Nullable = true), @p179='232' (Nullable = true), @p180='8', @p181='3454' (Nullable = true), @p182='2' (Nullable = true), @p183='3454', @p184='3454', @p185='T90282' (Size = 20), @p186='3454', @p187='900' (Nullable = true), @p188='232' (Nullable = true), @p189='8', @p190='3454' (Nullable = true), @p191='2' (Nullable = true), @p192='3454', @p193='3454', @p194='T90282' (Size = 20), @p195='3454', @p196='900' (Nullable = true), @p197='232' (Nullable = true), @p198='8', @p199='3454' (Nullable = true), @p200='2' (Nullable = true), @p201='3454', @p202='3454', @p203='T90282' (Size = 20), @p204='3454', @p205='900' (Nullable = true), @p206='232' (Nullable = true), @p207='8', @p208='3454' (Nullable = true), @p209='2' (Nullable = true), @p210='3454', @p211='3454', @p212='T90282' (Size = 20), @p213='3454', @p214='900' (Nullable = true), @p215='232' (Nullable = true), @p216='8', @p217='3454' (Nullable = true), @p218='2' (Nullable = true), @p219='3454', @p220='3454', @p221='T90282' (Size = 20), @p222='3454', @p223='900' (Nullable = true), @p224='232' (Nullable = true), @p225='8', @p226='3454' (Nullable = true), @p227='2' (Nullable = true), @p228='3454', @p229='3454', @p230='T90282' (Size = 20), @p231='3454', @p232='900' (Nullable = true), @p233='232' (Nullable = true), @p234='8', @p235='3454' (Nullable = true), @p236='2' (Nullable = true), @p237='3454', @p238='3454', @p239='T90282' (Size = 20), @p240='3454', @p241='900' (Nullable = true), @p242='232' (Nullable = true), @p243='8', @p244='3454' (Nullable = true), @p245='2' (Nullable = true), @p246='3454', @p247='3454', @p248='T90282' (Size = 20), @p249='3454', @p250='900' (Nullable = true), @p251='232' (Nullable = true), @p252='8', @p253='3454' (Nullable = true), @p254='2' (Nullable = true), @p255='3454', @p256='3454', @p257='T90282' (Size = 20), @p258='3454', @p259='900' (Nullable = true), @p260='232' (Nullable = true), @p261='8', @p262='3454' (Nullable = true), @p263='2' (Nullable = true), @p264='3454', @p265='3454', @p266='T90282' (Size = 20), @p267='3454', @p268='900' (Nullable = true), @p269='232' (Nullable = true), @p270='8', @p271='3454' (Nullable = true), @p272='2' (Nullable = true), @p273='3454', @p274='3454', @p275='T90282' (Size = 20), @p276='3454', @p277='900' (Nullable = true), @p278='232' (Nullable = true), @p279='8', @p280='3454' (Nullable = true)"], CommandType='Text', CommandTimeout='30']"
""SET NOCOUNT ON;
DECLARE @inserted0 TABLE ([LogId] int, [_Position] [int]);
MERGE [log].[Log] USING (
VALUES (@p47, @p48, @p49, @p50, @p51, @p52, @p53, @p54, @p55, 0),
(@p56, @p57, @p58, @p59, @p60, @p61, @p62, @p63, @p64, 1),
(@p65, @p66, @p67, @p68, @p69, @p70, @p71, @p72, @p73, 2),
(@p74, @p75, @p76, @p77, @p78, @p79, @p80, @p81, @p82, 3),
(@p83, @p84, @p85, @p86, @p87, @p88, @p89, @p90, @p91, 4),
(@p92, @p93, @p94, @p95, @p96, @p97, @p98, @p99, @p100, 5),
(@p101, @p102, @p103, @p104, @p105, @p106, @p107, @p108, @p109, 6),
(@p110, @p111, @p112, @p113, @p114, @p115, @p116, @p117, @p118, 7),
(@p119, @p120, @p121, @p122, @p123, @p124, @p125, @p126, @p127, 8),
(@p128, @p129, @p130, @p131, @p132, @p133, @p134, @p135, @p136, 9),
(@p137, @p138, @p139, @p140, @p141, @p142, @p143, @p144, @p145, 10),
(@p146, @p147, @p148, @p149, @p150, @p151, @p152, @p153, @p154, 11),
(@p155, @p156, @p157, @p158, @p159, @p160, @p161, @p162, @p163, 12),
(@p164, @p165, @p166, @p167, @p168, @p169, @p170, @p171, @p172, 13),
(@p173, @p174, @p175, @p176, @p177, @p178, @p179, @p180, @p181, 14),
(@p182, @p183, @p184, @p185, @p186, @p187, @p188, @p189, @p190, 15),
(@p191, @p192, @p193, @p194, @p195, @p196, @p197, @p198, @p199, 16),
(@p200, @p201, @p202, @p203, @p204, @p205, @p206, @p207, @p208, 17),
(@p209, @p210, @p211, @p212, @p213, @p214, @p215, @p216, @p217, 18),
(@p218, @p219, @p220, @p221, @p222, @p223, @p224, @p225, @p226, 19),
(@p227, @p228, @p229, @p230, @p231, @p232, @p233, @p234, @p235, 20),
(@p236, @p237, @p238, @p239, @p240, @p241, @p242, @p243, @p244, 21),
(@p245, @p246, @p247, @p248, @p249, @p250, @p251, @p252, @p253, 22),
(@p254, @p255, @p256, @p257, @p258, @p259, @p260, @p261, @p262, 23),
(@p263, @p264, @p265, @p266, @p267, @p268, @p269, @p270, @p271, 24),
(@p272, @p273, @p274, @p275, @p276, @p277, @p278, @p279, @p280, 25)) AS i ([AcademyId], [AppId], [DeviceId], [EmployeeId], [MessageId], [OriginalId], [SequentialId], [TenantId], [UserId], _Position) ON 1=0
WHEN NOT MATCHED THEN
INSERT ([AcademyId], [AppId], [DeviceId], [EmployeeId], [MessageId], [OriginalId], [SequentialId], [TenantId], [UserId])
VALUES (i.[AcademyId], i.[AppId], i.[DeviceId], i.[EmployeeId], i.[MessageId], i.[OriginalId], i.[SequentialId], i.[TenantId], i.[UserId])
OUTPUT INSERTED.[LogId], i._Position
INTO @inserted0;

SELECT [t].[LogId] FROM [log].[Log] t
INNER JOIN @inserted0 i ON ([t].[LogId] = [i].[LogId])
ORDER BY [i].[_Position];"

2018-06-13 17:12:01 DBG Executing DbCommand [Parameters=["@p281='418532', @p282='2018-06-13T16:11:57.3074235+00:00', @p283='0.4', @p284='Good' (Size = 50), @p285='20.3' (Nullable = true), @p286='2018-06-13T16:56:41.8231036+01:00', @p287='418555', @p288='2018-06-13T16:11:57.3405259+00:00', @p289='0.5', @p290='Good' (Size = 50), @p291='22.4' (Nullable = true), @p292='2018-06-13T16:51:41.8233120+01:00', @p293='418554', @p294='2018-06-13T16:11:57.3406167+00:00', @p295='0.6', @p296='Overheat' (Size = 50), @p297='32.4' (Nullable = true), @p298='2018-06-13T16:41:41.8233144+01:00', @p299='418553', @p300='2018-06-13T16:11:57.3422995+00:00', @p301='1', @p302='Good' (Size = 50), @p303='20.3' (Nullable = true), @p304='2018-06-13T05:11:41.8238020+01:00', @p305='418552', @p306='2018-06-13T16:11:57.3423548+00:00', @p307='0.75', @p308='Overheat' (Size = 50), @p309='30.4' (Nullable = true), @p310='2018-06-13T11:11:41.8240006+01:00', @p311='418551', @p312='2018-06-13T16:11:57.3424910+00:00', @p313='0.5', @p314='Over Voltage' (Size = 50), @p315='40.5' (Nullable = true), @p316='2018-06-13T16:11:41.8240025+01:00', @p317='418550', @p318='1' (Nullable = true), @p319='2018-06-13T16:11:41.8242812+01:00', @p320='2018-06-13T15:11:41.8243830+01:00', @p321='1' (Nullable = true), @p322='' (DbType = Int32), @p323='2018-06-13T15:41:41.8244762+01:00', @p324='2018-06-13T14:41:41.8245662+01:00', @p325='10' (Nullable = true), @p326='ss' (Size = 100), @p327='2018-06-13T16:11:57.3489556+00:00', @p328='\\Bridge\\Scripts\\sds' (Nullable = false) (Size = 1000), @p329='0', @p330='False' (Nullable = true), @p331='10' (Nullable = true), @p332='0', @p333='418549', @p334='1' (Nullable = true), @p335='2018-06-13T16:11:41.8253668+01:00', @p336='2018-06-13T15:11:41.8253691+01:00', @p337='2' (Nullable = true), @p338='5' (Nullable = true), @p339='2018-06-13T15:41:41.8253695+01:00', @p340='2018-06-13T14:41:41.8253703+01:00', @p341='10' (Nullable = true), @p342='sfjdsofjdsf[dsfdsfodhsfdsfoidsjfdssfds' (Size = 100), @p343='2018-06-13T16:11:57.3523276+00:00', @p344='\\Bridge\\Scripts\\Path\\To\\Guide1.zip' (Nullable = false) (Size = 1000), @p345='1', @p346='False' (Nullable = true), @p347='5' (Nullable = true), @p348='0', @p349='418545', @p350='2018-06-13T16:11:57.3689908+00:00', @p351='Device On' (Nullable = false) (Size = 200), @p352='2018-06-13T14:11:41.8307572+01:00', @p353='418546', @p354='2018-06-13T16:11:57.3689833+00:00', @p355='User Depart' (Nullable = false) (Size = 200), @p356='2018-06-13T16:11:41.8307560+01:00', @p357='418544', @p358='2018-06-13T16:11:57.3689951+00:00', @p359='Device Off' (Nullable = false) (Size = 200), @p360='2018-06-13T16:11:41.8307584+01:00', @p361='418548', @p362='2018-06-13T16:11:57.3642126+00:00', @p363='User Arrive' (Nullable = false) (Size = 200), @p364='2018-06-13T13:11:41.8301114+01:00', @p365='418547', @p366='2018-06-13T16:11:57.3653672+00:00', @p367='User Login' (Nullable = false) (Size = 200), @p368='2018-06-13T14:11:41.8307524+01:00', @p369='418543', @p370='1' (Nullable = true), @p371='123', @p372='23b70c30d1194fbdb23be4dfcd3eb256' (Size = 100), @p373='2018-06-13T16:11:57.3710762+00:00', @p374='\\Bridge\\Scripts\\Path\\To\\Guide1.zip' (Nullable = false) (Size = 1000), @p375='0', @p376='2018-06-13T13:11:41.8329773+01:00', @p377='418542', @p378='2' (Nullable = true), @p379='456', @p380='fbc76c18df2f421681359d844ac330bc' (Size = 100), @p381='2018-06-13T16:11:57.3721495+00:00', @p382='\\Bridge\\Scripts\\Path\\To\\Guide2.zip' (Nullable = false) (Size = 1000), @p383='1', @p384='2018-06-13T13:11:41.8329809+01:00', @p385='418541', @p386='1' (Nullable = true), @p387='123', @p388='23b70c30d1194fbdb23be4dfcd3eb256' (Size = 100), @p389='2018-06-13T16:11:57.3721795+00:00', @p390='\\Bridge\\Scripts\\Path\\To\\Guide1.zip' (Nullable = false) (Size = 1000), @p391='0', @p392='2018-06-13T13:11:41.8318409+01:00', @p393='418540', @p394='1', @p395='2018-06-13T00:00:00' (DbType = Date), @p396='100', @p397='2018-06-13T16:11:57.3738415+00:00', @p398='2018-06-13T17:11:41.8324776+01:00' (Nullable = true), @p399='418539', @p400='127374182', @p401='2018-06-13T16:11:57.3777203+00:00', @p402='2018-06-13T14:11:41.8334423+01:00', @p403='536870912' (Nullable = true), @p404='409496730', @p405='418538', @p406='117374182', @p407='2018-06-13T16:11:57.3787673+00:00', @p408='2018-06-13T15:11:41.8338427+01:00', @p409='536870912' (Nullable = true), @p410='419496730', @p411='418537', @p412='107374182', @p413='2018-06-13T16:11:57.3787925+00:00', @p414='2018-06-13T16:11:41.8338478+01:00', @p415='536870912' (Nullable = true), @p416='429496730', @p417='418556', @p418='0.1' (Nullable = true), @p419='1', @p420='-0.1', @p421='2018-06-13T16:11:57.3910273+00:00', @p422='2018-06-13T17:11:41.8424721+01:00', @p423='418536', @p424='0' (Nullable = true), @p425='0.231242343', @p426='32.34234323', @p427='2018-06-13T16:11:57.3807241+00:00', @p428='2018-06-13T16:11:41.8367110+01:00', @p429='418535', @p430='0' (Nullable = true), @p431='0.231242303', @p432='32.34234023', @p433='2018-06-13T16:11:57.3811927+00:00', @p434='2018-06-13T16:41:41.8368740+01:00', @p435='418534', @p436='0.1' (Nullable = true), @p437='1', @p438='-0.1', @p439='2018-06-13T16:11:57.3903925+00:00', @p440='2018-06-13T17:11:41.8376319+01:00', @p441='418533', @p442='0.1' (Nullable = true), @p443='1', @p444='-0.1', @p445='2018-06-13T16:11:57.3910123+00:00', @p446='2018-06-13T17:11:41.8424571+01:00', @p447='418557', @p448='0.1' (Nullable = true), @p449='1', @p450='-0.1', @p451='2018-06-13T16:11:57.3910332+00:00', @p452='2018-06-13T17:11:41.8424784+01:00'"], CommandType='Text', CommandTimeout='30']"
""SET NOCOUNT ON;
INSERT INTO [log].[BatteryLevel] ([LogId], [LastUpdated], [Level], [Status], [Temperature], [Timestamp])
VALUES (@p281, @p282, @p283, @p284, @p285, @p286),
(@p287, @p288, @p289, @p290, @p291, @p292),
(@p293, @p294, @p295, @p296, @p297, @p298),
(@p299, @p300, @p301, @p302, @p303, @p304),
(@p305, @p306, @p307, @p308, @p309, @p310),
(@p311, @p312, @p313, @p314, @p315, @p316);
INSERT INTO [log].[CompletedGuide] ([LogId], [ActivityId], [ActualEnd], [ActualStart], [ClassroomId], [CompletedPages], [ExpectedEnd], [ExpectedStart], [GuideId], [Hash], [LastUpdated], [Path], [PercentageCompleted], [RenderedSuccessfully], [TotalPages], [Type])
VALUES (@p317, @p318, @p319, @p320, @p321, @p322, @p323, @p324, @p325, @p326, @p327, @p328, @p329, @p330, @p331, @p332),
(@p333, @p334, @p335, @p336, @p337, @p338, @p339, @p340, @p341, @p342, @p343, @p344, @p345, @p346, @p347, @p348);
INSERT INTO [log].[Event] ([LogId], [LastUpdated], [Name], [Timestamp])
VALUES (@p349, @p350, @p351, @p352),
(@p353, @p354, @p355, @p356),
(@p357, @p358, @p359, @p360),
(@p361, @p362, @p363, @p364),
(@p365, @p366, @p367, @p368);
INSERT INTO [log].[Guide] ([LogId], [ActivityId], [GuideId], [Hash], [LastUpdated], [Path], [Status], [Timestamp])
VALUES (@p369, @p370, @p371, @p372, @p373, @p374, @p375, @p376),
(@p377, @p378, @p379, @p380, @p381, @p382, @p383, @p384),
(@p385, @p386, @p387, @p388, @p389, @p390, @p391, @p392);
INSERT INTO [log].[GuideCount] ([LogId], [Actual], [Date], [Expected], [LastUpdated], [Timestamp])
VALUES (@p393, @p394, @p395, @p396, @p397, @p398);
INSERT INTO [log].[MemoryLevel] ([LogId], [Free], [LastUpdated], [Timestamp], [Total], [Used])
VALUES (@p399, @p400, @p401, @p402, @p403, @p404),
(@p405, @p406, @p407, @p408, @p409, @p410),
(@p411, @p412, @p413, @p414, @p415, @p416);
INSERT INTO [log].[Position] ([LogId], [Accuracy], [CoordinatesLatitude], [CoordinatesLongitude], [LastUpdated], [Timestamp])
VALUES (@p417, @p418, @p419, @p420, @p421, @p422),
(@p423, @p424, @p425, @p426, @p427, @p428),
(@p429, @p430, @p431, @p432, @p433, @p434),
(@p435, @p436, @p437, @p438, @p439, @p440),
(@p441, @p442, @p443, @p444, @p445, @p446),
(@p447, @p448, @p449, @p450, @p451, @p452);"

2018-06-13 17:12:02 DBG Executing DbCommand [Parameters=["@p453='418532', @p454='418532', @p455='2018-06-13T16:11:57.3074235+00:00', @p456='2', @p457='AC' (Size = 100), @p458='418555', @p459='418555', @p460='2018-06-13T16:11:57.3405259+00:00', @p461='3', @p462='AC' (Size = 100), @p463='418554', @p464='418554', @p465='2018-06-13T16:11:57.3406167+00:00', @p466='2', @p467='AC' (Size = 100), @p468='418549', @p469='360', @p470='2018-06-13T16:11:57.3542619+00:00', @p471='1' (Nullable = true), @p472='False' (Nullable = true), @p473='0.2' (Nullable = true), @p474='2018-06-13T15:11:41.8257299+01:00', @p475='418549', @p476='360', @p477='2018-06-13T16:11:57.3555808+00:00', @p478='2' (Nullable = true), @p479='False' (Nullable = true), @p480='0.4' (Nullable = true), @p481='2018-06-13T15:17:41.8258184+01:00', @p482='418549', @p483='360', @p484='2018-06-13T16:11:57.3555831+00:00', @p485='3' (Nullable = true), @p486='False' (Nullable = true), @p487='0.6' (Nullable = true), @p488='2018-06-13T15:23:41.8258203+01:00', @p489='418549', @p490='360', @p491='2018-06-13T16:11:57.3555835+00:00', @p492='4' (Nullable = true), @p493='True' (Nullable = true), @p494='0.8' (Nullable = true), @p495='2018-06-13T15:29:41.8258211+01:00', @p496='418549', @p497='2159', @p498='2018-06-13T16:11:57.3555839+00:00', @p499='5' (Nullable = true), @p500='False' (Nullable = true), @p501='1' (Nullable = true), @p502='2018-06-13T15:35:41.8258219+01:00', @p503='', @p504='' (DbType = DateTimeOffset), @p505='', @p506='418547', @p507='' (DbType = Guid), @p508='123' (Nullable = true), @p509='2018-06-13T16:11:57.3667066+00:00', @p510='UserId' (Nullable = false) (Size = 100), @p511='' (DbType = Int32), @p512='2', @p513='123' (Size = 1000), @p514='', @p515='' (DbType = DateTimeOffset), @p516='', @p517='418547', @p518='' (DbType = Guid), @p519='' (DbType = Int64), @p520='2018-06-13T16:11:57.3687926+00:00', @p521='EmployeeId' (Nullable = false) (Size = 100), @p522='' (DbType = Int32), @p523='0', @p524='T90282' (Size = 1000), @p525='418534', @p526='59' (Nullable = true), @p527='2018-06-13T17:12:41.8371381+01:00' (Nullable = true), @p528='2018-06-13T16:11:57.3894396+00:00', @p529='418534' (Nullable = true), @p530='2018-06-13T17:11:41.8372700+01:00', @p531='0', @p532='418533', @p533='59' (Nullable = true), @p534='2018-06-13T18:12:41.8424476+01:00' (Nullable = true), @p535='2018-06-13T16:11:57.3910111+00:00', @p536='418533' (Nullable = true), @p537='2018-06-13T18:11:41.8424551+01:00', @p538='1', @p539='418556', @p540='59' (Nullable = true), @p541='2018-06-13T19:12:41.8424693+01:00' (Nullable = true), @p542='2018-06-13T16:11:57.3910269+00:00', @p543='418556' (Nullable = true), @p544='2018-06-13T19:11:41.8424709+01:00', @p545='2', @p546='418557', @p547='59' (Nullable = true), @p548='2018-06-13T20:12:41.8424760+01:00' (Nullable = true), @p549='2018-06-13T16:11:57.3910328+00:00', @p550='418557' (Nullable = true), @p551='2018-06-13T20:11:41.8424772+01:00', @p552='0'"], CommandType='Text', CommandTimeout='30']"
""SET NOCOUNT ON;
INSERT INTO [log].[BatteryEvent] ([LogId], [BatteryLevelLogId], [LastUpdated], [Status], [Type])
VALUES (@p453, @p454, @p455, @p456, @p457),
(@p458, @p459, @p460, @p461, @p462),
(@p463, @p464, @p465, @p466, @p467);
DECLARE @inserted3 TABLE ([PageId] int, [_Position] [int]);
MERGE [log].[Page] USING (
VALUES (@p468, @p469, @p470, @p471, @p472, @p473, @p474, 0),
(@p475, @p476, @p477, @p478, @p479, @p480, @p481, 1),
(@p482, @p483, @p484, @p485, @p486, @p487, @p488, 2),
(@p489, @p490, @p491, @p492, @p493, @p494, @p495, 3),
(@p496, @p497, @p498, @p499, @p500, @p501, @p502, 4)) AS i ([CompletedGuideId], [DurationSeconds], [LastUpdated], [PageNumber], [Pause], [PercentageCompleted], [Timestamp], _Position) ON 1=0
WHEN NOT MATCHED THEN
INSERT ([CompletedGuideId], [DurationSeconds], [LastUpdated], [PageNumber], [Pause], [PercentageCompleted], [Timestamp])
VALUES (i.[CompletedGuideId], i.[DurationSeconds], i.[LastUpdated], i.[PageNumber], i.[Pause], i.[PercentageCompleted], i.[Timestamp])
OUTPUT INSERTED.[PageId], i._Position
INTO @inserted3;

SELECT [t].[PageId] FROM [log].[Page] t
INNER JOIN @inserted3 i ON ([t].[PageId] = [i].[PageId])
ORDER BY [i].[_Position];

DECLARE @inserted8 TABLE ([PropertyId] int, [_Position] [int]);
MERGE [log].[Property] USING (
VALUES (@p503, @p504, @p505, @p506, @p507, @p508, @p509, @p510, @p511, @p512, @p513, 0),
(@p514, @p515, @p516, @p517, @p518, @p519, @p520, @p521, @p522, @p523, @p524, 1)) AS i ([BoolValue], [DateTimeValue], [DoubleValue], [EventId], [GuidValue], [IntegerValue], [LastUpdated], [Name], [TimeSpanSecondsValue], [Type], [Value], _Position) ON 1=0
WHEN NOT MATCHED THEN
INSERT ([BoolValue], [DateTimeValue], [DoubleValue], [EventId], [GuidValue], [IntegerValue], [LastUpdated], [Name], [TimeSpanSecondsValue], [Type], [Value])
VALUES (i.[BoolValue], i.[DateTimeValue], i.[DoubleValue], i.[EventId], i.[GuidValue], i.[IntegerValue], i.[LastUpdated], i.[Name], i.[TimeSpanSecondsValue], i.[Type], i.[Value])
OUTPUT INSERTED.[PropertyId], i._Position
INTO @inserted8;

SELECT [t].[PropertyId] FROM [log].[Property] t
INNER JOIN @inserted8 i ON ([t].[PropertyId] = [i].[PropertyId])
ORDER BY [i].[_Position];

INSERT INTO [log].[Synchronization] ([LogId], [DurationSeconds], [End], [LastUpdated], [PositionLogId], [Start], [Type])
VALUES (@p525, @p526, @p527, @p528, @p529, @p530, @p531),
(@p532, @p533, @p534, @p535, @p536, @p537, @p538),
(@p539, @p540, @p541, @p542, @p543, @p544, @p545),
(@p546, @p547, @p548, @p549, @p550, @p551, @p552);"

2018-06-13 17:12:02 DBG Executing DbCommand [Parameters=["@p0='1024' (Nullable = true), @p1='899' (Nullable = true), @p2='2018-06-13T17:11:42.7379462+01:00' (Nullable = true), @p3='1.1' (Size = 10), @p4='2018-06-13T16:11:57.3857573+00:00', @p5='10' (Nullable = true), @p6='Guide' (Nullable = false) (Size = 1000), @p7='dce6d641-a766-457a-b3f1-ece8e0d8948f' (Nullable = true), @p8='1' (Nullable = true), @p9='2018-06-13T17:11:41.8386010+01:00', @p10='0', @p11='204' (Nullable = true), @p12='418534', @p13='512' (Nullable = true), @p14='http://example.com' (Size = 4000), @p15='GET' (Size = 7)"], CommandType='Text', CommandTimeout='30']"
""SET NOCOUNT ON;
INSERT INTO [log].[SynchronizationItem] ([DownloadSize], [DurationMilliseconds], [End], [Http], [LastUpdated], [LatencyMilliseconds], [Name], [RequestId], [RetryCount], [Start], [Status], [StatusCode], [SynchronizationId], [UploadSize], [Url], [Verb])
VALUES (@p0, @p1, @p2, @p3, @p4, @p5, @p6, @p7, @p8, @p9, @p10, @p11, @p12, @p13, @p14, @p15);
SELECT [SynchronizationItemId]
FROM [log].[SynchronizationItem]
WHERE @@ROWCOUNT = 1 AND [SynchronizationItemId] = scope_identity();"

2018-06-13 17:12:02 DBG Executing DbCommand [Parameters=["@p0='386' (Nullable = true), @p1='699' (Nullable = true), @p2='2018-06-13T17:11:43.4390400+01:00' (Nullable = true), @p3='2.0' (Size = 10), @p4='2018-06-13T16:11:57.3878380+00:00', @p5='20' (Nullable = true), @p6='Guide' (Nullable = false) (Size = 1000), @p7='9fe1356a-23b4-41dc-9ef3-001a60f0bf7a' (Nullable = true), @p8='1' (Nullable = true), @p9='2018-06-13T17:11:42.7390436+01:00', @p10='2', @p11='-1' (Nullable = true), @p12='418534', @p13='256' (Nullable = true), @p14='http://example.com' (Size = 4000), @p15='GET' (Size = 7)"], CommandType='Text', CommandTimeout='30']"
""SET NOCOUNT ON;
INSERT INTO [log].[SynchronizationItem] ([DownloadSize], [DurationMilliseconds], [End], [Http], [LastUpdated], [LatencyMilliseconds], [Name], [RequestId], [RetryCount], [Start], [Status], [StatusCode], [SynchronizationId], [UploadSize], [Url], [Verb])
VALUES (@p0, @p1, @p2, @p3, @p4, @p5, @p6, @p7, @p8, @p9, @p10, @p11, @p12, @p13, @p14, @p15);
SELECT [SynchronizationItemId]
FROM [log].[SynchronizationItem]
WHERE @@ROWCOUNT = 1 AND [SynchronizationItemId] = scope_identity();"

Answer 1

I think you should check the Isolation Level of the transactions executed by your application. Usually the default Isolation Level of MSSQL databases is READ COMMITED and transactions executed through EF would respect that configuration.

If that is so, though you haven't shared your code, it seems that these two transactions are executing at almost the same time and that would cause the error you are getting:

2018-06-13 17:12:02 DBG Executing DbCommand [Parameters=["@p0='1024' (Nullable = 
true), @p1='899' (Nullable = true), @p2='2018-06-13T17:11:42.7379462+01:00' (Nullable = true), @p3='1.1' (Size = 10), @p4='2018-06-13T16:11:57.3857573+00:00', @p5='10' (Nullable = true), @p6='Guide' (Nullable = false) (Size = 1000), @p7='dce6d641-a766-457a-b3f1-ece8e0d8948f' (Nullable = true), @p8='1' (Nullable = true), @p9='2018-06-13T17:11:41.8386010+01:00', @p10='0', @p11='204' (Nullable = true), @p12='418534', @p13='512' (Nullable = true), @p14='http://example.com' (Size = 4000), @p15='GET' (Size = 7)"], CommandType='Text', CommandTimeout='30']"
""SET NOCOUNT ON;
INSERT INTO [log].[SynchronizationItem] ([DownloadSize], [DurationMilliseconds], [End], [Http], [LastUpdated], [LatencyMilliseconds], [Name], [RequestId], [RetryCount], [Start], [Status], [StatusCode], [SynchronizationId], [UploadSize], [Url], [Verb])
VALUES (@p0, @p1, @p2, @p3, @p4, @p5, @p6, @p7, @p8, @p9, @p10, @p11, @p12, @p13, @p14, @p15);
SELECT [SynchronizationItemId]
FROM [log].[SynchronizationItem]
WHERE @@ROWCOUNT = 1 AND [SynchronizationItemId] = scope_identity();"

2018-06-13 17:12:02 DBG Executing DbCommand [Parameters=["@p0='386' (Nullable = true), @p1='699' (Nullable = true), @p2='2018-06-13T17:11:43.4390400+01:00' (Nullable = true), @p3='2.0' (Size = 10), @p4='2018-06-13T16:11:57.3878380+00:00', @p5='20' (Nullable = true), @p6='Guide' (Nullable = false) (Size = 1000), @p7='9fe1356a-23b4-41dc-9ef3-001a60f0bf7a' (Nullable = true), @p8='1' (Nullable = true), @p9='2018-06-13T17:11:42.7390436+01:00', @p10='2', @p11='-1' (Nullable = true), @p12='418534', @p13='256' (Nullable = true), @p14='http://example.com' (Size = 4000), @p15='GET' (Size = 7)"], CommandType='Text', CommandTimeout='30']"
""SET NOCOUNT ON;
INSERT INTO [log].[SynchronizationItem] ([DownloadSize], [DurationMilliseconds], [End], [Http], [LastUpdated], [LatencyMilliseconds], [Name], [RequestId], [RetryCount], [Start], [Status], [StatusCode], [SynchronizationId], [UploadSize], [Url], [Verb])
VALUES (@p0, @p1, @p2, @p3, @p4, @p5, @p6, @p7, @p8, @p9, @p10, @p11, @p12, @p13, @p14, @p15);
SELECT [SynchronizationItemId]
FROM [log].[SynchronizationItem]
WHERE @@ROWCOUNT = 1 AND [SynchronizationItemId] = scope_identity();"

It may be possible that when the read operation (SELECT..) from the second transaction is locked by the write operation (INSERT...) from the first transaction, at the same time, the read operation from the first transaction is locked by the write operation from the second transaction. That would cause the deadlock.