* fix FOR UPDATE is not allowed with window functions @ `AuthorRevi…

…sionSaver.SaveAuthorRevisions()`

* fix `IEnumerable<>.Conatins(IEnumerable<>, IEqualityComparer<>)` cannot be translated @ `ReplySaver.SaveReplySignatures()`

* fix quoting string literal & identifiers for Postgres flavor
* replace MySQL specified `IFNULL()` with standard `COALESCE()`
- setting timeout variables for MySQL
@ `PushAllPostContentsIntoSonicWorker.DoWork()`
@ crawler

* suppress Roslyn analyzer rule `AV1568` in `ExifGpsTagValuesParser.ParseGpsCoordinateOrNull()` & `ExifDateTimeTagValuesParser.ParseExifDateTimeOrNull()` @ MetadataConsumer.cs
@ imagePipeline

+ virtual methods `OnBuildingNpgsqlDataSource()`, `GetNpgsqlDataSource()` & method `GetNpgsqlDataSourceFactory()` for mapping enum types in Postgres
* rename virtual method `OnConfiguringMysql()` to `OnConfiguringNpgsql()`
* rename static field `SelectForUpdateCommandInterceptorInstace` to `SelectForUpdateCommandInterceptorSingleton`
@ TbmDbContext.cs

+ class `NpgsqlCamelCaseNameTranslator` for converting enum value names
@ shared
@ c#

c#/crawler/src/Db/CrawlerDbContext.cs

@@ -1,4 +1,5 @@
 using Microsoft.EntityFrameworkCore.Infrastructure;
+using Npgsql;
 using static tbm.Crawler.Db.Revision.ReplyRevision;
 using static tbm.Crawler.Db.Revision.SubReplyRevision;
 using static tbm.Crawler.Db.Revision.ThreadRevision;
@@ -8,6 +9,8 @@ namespace tbm.Crawler.Db;
 
 public class CrawlerDbContext(Fid fid) : TbmDbContext<CrawlerDbContext.ModelCacheKeyFactory>
 {
+    private static Lazy<NpgsqlDataSource>? _dataSourceSingleton;
+
     public CrawlerDbContext() : this(fid: 0) { }
     public delegate CrawlerDbContext NewDefault();
     public delegate CrawlerDbContext New(Fid fid);
@@ -102,6 +105,13 @@ protected override void OnModelCreating(ModelBuilder b)
         b.Entity<Forum>().ToTable("tbm_forum");
     }
 
+    protected override void OnBuildingNpgsqlDataSource(NpgsqlDataSourceBuilder builder) =>
+        builder.MapEnum<PostType>("tbmcr_triggeredBy", new NpgsqlCamelCaseNameTranslator());
+
+    [SuppressMessage("Critical Code Smell", "S2696:Instance members should not write to \"static\" fields")]
+    protected override Lazy<NpgsqlDataSource> GetNpgsqlDataSource(string? connectionString) =>
+        _dataSourceSingleton ??= GetNpgsqlDataSourceFactory(connectionString);
+
     public class ModelCacheKeyFactory : IModelCacheKeyFactory
     { // https://stackoverflow.com/questions/51864015/entity-framework-map-model-class-to-table-at-run-time/51899590#51899590
         // https://docs.microsoft.com/en-us/ef/core/modeling/dynamic-model

c#/crawler/src/Tieba/Crawl/Saver/AuthorRevisionSaver.cs

@@ -1,4 +1,4 @@
-using LinqToDB.DataProvider.MySql;
+using LinqToDB.DataProvider.PostgreSQL;
 
 namespace tbm.Crawler.Tieba.Crawl.Saver;
 
@@ -51,10 +51,12 @@ private void SaveAuthorRevisions<TPost, TRevision, TValue>(
     {
         Helper.GetNowTimestamp(out var now);
         var existingRevisionOfExistingUsers = dbSet.AsNoTracking()
-            .Where(e => e.Fid == db.Fid && posts.Select(p => p.AuthorUid).Distinct().Contains(e.Uid))
+            .Where(e => e.Fid == db.Fid
+                        && posts.Select(p => p.AuthorUid).Distinct().Contains(e.Uid))
             .Select(latestRevisionProjectionFactory)
+            .AsCte() // https://stackoverflow.com/questions/49854322/usage-of-for-update-in-window-function-postgres#comment86726589_49854322
             .Where(e => e.Rank == 1)
-            .AsMySql().ForUpdateHint()
+            .AsPostgreSQL().ForUpdateHint()
             .ToLinqToDB().AsEnumerable()
             .Join(posts, e => e.Uid, p => p.AuthorUid, (e, p) =>
             (

c#/crawler/src/Tieba/Crawl/Saver/Post/ReplySaver.cs

@@ -142,7 +142,9 @@ private Action SaveReplySignatures(CrawlerDbContext db, IEnumerable<ReplyPost> r
         var existingSignatures = (
             from s in db.ReplySignatures.AsTracking().ForUpdate()
             where uniqueSignatures.Select(us => us.Id).Contains(s.SignatureId)
-                  && uniqueSignatures.Select(us => us.XxHash3).Contains(s.XxHash3, new ByteArrayEqualityComparer())
+
+                  // server side eval doesn't need ByteArrayEqualityComparer
+                  && uniqueSignatures.Select(us => us.XxHash3).Contains(s.XxHash3)
             select s
         ).ToList();
         (from existing in existingSignatures

c#/crawler/src/Worker/PushAllPostContentsIntoSonicWorker.cs

@@ -22,9 +22,9 @@ protected override async Task DoWork(CancellationToken stoppingToken)
 #pragma warning restore IDISP004 // Don't ignore created IDisposable
             .Query<(Fid Fid, int ReplyCount, int SubReplyCount)>(
                 string.Join(" UNION ALL ", (from f in db.Forums select f.Fid).AsEnumerable().Select(fid =>
-                    $"SELECT {fid} AS Fid,"
-                    + $"IFNULL((SELECT id FROM tbmc_f{fid}_reply ORDER BY id DESC LIMIT 1), 0) AS ReplyCount,"
-                    + $"IFNULL((SELECT id FROM tbmc_f{fid}_subReply ORDER BY id DESC LIMIT 1), 0) AS SubReplyCount")))
+                    $"SELECT '{fid}',"
+                    + $"COALESCE((SELECT id FROM \"tbmc_f{fid}_reply\" ORDER BY id DESC LIMIT 1), 0),"
+                    + $"COALESCE((SELECT id FROM \"tbmc_f{fid}_subReply\" ORDER BY id DESC LIMIT 1), 0)")))
             .ToList();
         var forumCount = forumPostCountsTuples.Count * 2; // reply and sub reply
         var totalPostCount = forumPostCountsTuples.Sum(t => t.ReplyCount)
@@ -36,11 +36,6 @@ protected override async Task DoWork(CancellationToken stoppingToken)
             await using var dbFactory = dbContextFactory();
             var dbWithFid = dbFactory.Value(fid);
 
-            // enlarge the default mysql connection read/write timeout to prevent it close connection while pushing
-            // since pushing post contents into sonic is slower than fetching records from mysql, aka back-pressure
-            _ = await dbWithFid.Database.ExecuteSqlRawAsync(
-                "SET SESSION net_read_timeout = 3600; SET SESSION net_write_timeout = 3600;", stoppingToken);
-
             _ = await pusher.Ingest.FlushBucketAsync($"{pusher.CollectionPrefix}replies_content", $"f{fid}");
             pushedPostCount += PushPostContentsWithTiming(fid, forumIndex - 1, forumCount, "replies",
                 replyCount, totalPostCount, pushedPostCount, dbWithFid.ReplyContents.AsNoTracking(),

c#/imagePipeline/src/Consumer/MetadataConsumer.cs

@@ -201,7 +201,9 @@ private static class ExifGpsTagValuesParser
         public static Point? ParseGpsCoordinateOrNull(
             IEnumerable<IExifValue> allTagValues,
             IEnumerable<Rational>? latitude,
+#pragma warning disable AV1568 // Parameter value should not be overwritten in method body
             string? latitudeRef,
+#pragma warning restore AV1568 // Parameter value should not be overwritten in method body
             IEnumerable<Rational>? longitude,
             string? longitudeRef)
         {
@@ -253,7 +255,9 @@ private static double ConvertDmsToDd(IReadOnlyList<double> dms)
 
     private static partial class ExifDateTimeTagValuesParser
     {
+#pragma warning disable AV1568 // Parameter value should not be overwritten in method body
         public static DateTimeAndOffset? ParseExifDateTimeOrNull(string? exifDateTime, string? exifFractionalSeconds)
+#pragma warning restore AV1568 // Parameter value should not be overwritten in method body
         { // https://gist.github.com/thanatos/eee17100476a336a711e
             // tested inputs with valid results:
             // "2019:02:07 21:238"         => "2019/2/7 21:23:08"  , ""

c#/imagePipeline/src/Db/ImagePipelineDbContext.cs

@@ -1,4 +1,5 @@
 using Microsoft.EntityFrameworkCore.Infrastructure;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Infrastructure;
 using static tbm.ImagePipeline.Db.ImageMetadata;
 
 namespace tbm.ImagePipeline.Db;
@@ -20,7 +21,7 @@ public ImagePipelineDbContext() : this(fid: 0, script: "") { }
     private Fid Fid { get; } = fid;
     private string Script { get; } = script;
 
-    protected override void OnConfiguringMysql(MySqlDbContextOptionsBuilder builder) => builder.UseNetTopologySuite();
+    protected override void OnConfiguringNpgsql(NpgsqlDbContextOptionsBuilder builder) => builder.UseNetTopologySuite();
 
     [SuppressMessage("Style", "IDE0058:Expression value is never used")]
     protected override void OnModelCreating(ModelBuilder b)

c#/shared/src/NpgsqlCamelCaseNameTranslator.cs

@@ -0,0 +1,14 @@
+using System.Globalization;
+using Npgsql;
+
+namespace tbm.Shared;
+
+public class NpgsqlCamelCaseNameTranslator : INpgsqlNameTranslator
+{
+    public string TranslateTypeName(string clrName) => TranslateMemberName(clrName);
+
+    /// <see>https://github.com/efcore/EFCore.NamingConventions/blob/0d19b13a8e62ec20779c3cca03c27f200b5b7458/EFCore.NamingConventions/Internal/CamelCaseNameRewriter.cs#L13</see>
+    /// <see>https://github.com/npgsql/npgsql/pull/1690</see>
+    public string TranslateMemberName(string clrName) =>
+        char.ToLower(clrName[0], CultureInfo.InvariantCulture) + clrName[1..];
+}

c#/shared/src/TbmDbContext.cs

@@ -7,13 +7,15 @@
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.Logging;
 using NLog.Extensions.Logging;
+using Npgsql;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Infrastructure;
 using LogLevel = Microsoft.Extensions.Logging.LogLevel;
 
 namespace tbm.Shared;
 
 public abstract class TbmDbContext : DbContext
 {
-    protected static readonly SelectForUpdateCommandInterceptor SelectForUpdateCommandInterceptorInstance = new();
+    protected static readonly SelectForUpdateCommandInterceptor SelectForUpdateCommandInterceptorSingleton = new();
 
     [SuppressMessage("Style", "CC0072:Remove Async termination when method is not asynchronous.", Justification = "https://github.com/code-cracker/code-cracker/issues/1086")]
     protected sealed class SelectForUpdateCommandInterceptor : DbCommandInterceptor
@@ -72,10 +74,9 @@ public class TbmDbContext<TModelCacheKeyFactory> : TbmDbContext
     [SuppressMessage("Style", "IDE0058:Expression value is never used")]
     protected override void OnConfiguring(DbContextOptionsBuilder options)
     {
-        var connectionString = Config.GetConnectionString("Main");
-        options.UseMySql(connectionString!, ServerVersion.AutoDetect(connectionString), OnConfiguringMysql)
+        options.UseNpgsql(GetNpgsqlDataSource(Config.GetConnectionString("Main")).Value, OnConfiguringNpgsql)
             .ReplaceService<IModelCacheKeyFactory, TModelCacheKeyFactory>()
-            .AddInterceptors(SelectForUpdateCommandInterceptorInstance)
+            .AddInterceptors(SelectForUpdateCommandInterceptorSingleton)
             .UseCamelCaseNamingConvention();
 
         var dbSettings = Config.GetSection("DbSettings");
@@ -102,5 +103,17 @@ protected override void OnModelCreating(ModelBuilder b)
     protected void OnModelCreatingWithFid(ModelBuilder b, uint fid) =>
         b.Entity<ReplyContentImage>().ToTable($"tbmc_f{fid}_reply_content_image");
 
-    protected virtual void OnConfiguringMysql(MySqlDbContextOptionsBuilder builder) { }
+    protected virtual void OnConfiguringNpgsql(NpgsqlDbContextOptionsBuilder builder) { }
+
+    protected virtual void OnBuildingNpgsqlDataSource(NpgsqlDataSourceBuilder builder) { }
+
+    protected virtual Lazy<NpgsqlDataSource> GetNpgsqlDataSource(string? connectionString) =>
+        throw new NotSupportedException();
+
+    protected Lazy<NpgsqlDataSource> GetNpgsqlDataSourceFactory(string? connectionString) => new(() =>
+    {
+        var dataSourceBuilder = new NpgsqlDataSourceBuilder(connectionString);
+        OnBuildingNpgsqlDataSource(dataSourceBuilder);
+        return dataSourceBuilder.Build();
+    });
 }