merge: SQL dialect+chunking review findings resolved (Driver.Sql-002, Driver.Sql.Dialect-001/-002/-003)

This commit is contained in:
Joseph Doherty
2026-08-10 08:06:13 -04:00
16 changed files with 648 additions and 37 deletions
@@ -65,6 +65,9 @@ public sealed class ColonMarkerDialect : ISqlDialect
/// <inheritdoc/>
public DbProviderFactory Factory => Inner.Factory;
/// <inheritdoc/>
public int MaxBindParameters => Inner.MaxBindParameters;
/// <inheritdoc/>
public string LivenessSql => Inner.LivenessSql;
@@ -165,13 +165,45 @@ public class OracleDialectTests
=> Should.Throw<ArgumentException>(() => new OracleDialect().QuoteIdentifier(ident));
[Fact]
public void QuoteIdentifier_acceptsExactly128Chars_andRejects129()
public void QuoteIdentifier_acceptsExactly128Bytes_andRejects129()
{
var d = new OracleDialect();
d.QuoteIdentifier(new string('a', 128)).ShouldBe("\"" + new string('a', 128) + "\"");
Should.Throw<ArgumentException>(() => d.QuoteIdentifier(new string('a', 129)));
}
/// <summary>
/// Oracle 12.2's 128 is a <b>byte</b> ceiling in the database character set (UTF-8 on any modern
/// estate), so a 65-character Cyrillic name is 130 bytes and the server rejects it with
/// <c>ORA-00972</c>. Measuring UTF-16 code units here would pass it through to fail at the server
/// instead — for a reason this dialect could have named.
/// </summary>
[Fact]
public void QuoteIdentifier_measuresTheCeilingInUtf8Bytes_notCharacters()
{
var d = new OracleDialect();
// 64 Cyrillic characters = 128 UTF-8 bytes — exactly at the limit.
d.QuoteIdentifier(new string('б', 64)).ShouldBe("\"" + new string('б', 64) + "\"");
// 65 characters = 130 bytes. A character-counting ceiling waves this through.
Should.Throw<ArgumentException>(() => d.QuoteIdentifier(new string('б', 65)));
}
// ---- bind-parameter ceiling ----
/// <summary>
/// 1000 is the <c>IN</c>-expression-list limit (<c>ORA-01795</c>), NOT Oracle's much larger 64k bind
/// count — the seam has to report the limit the planner's <c>IN (:p_k0, …)</c> list actually hits, or
/// it would chunk to a size the server still refuses.
/// </summary>
[Fact]
public void MaxBindParameters_isTheInListLimit_notTheLargerBindVariableCount()
{
new OracleDialect().MaxBindParameters.ShouldBe(1000);
new OracleDialect().MaxBindParameters.ShouldBeLessThan(new PostgresDialect().MaxBindParameters);
}
// ---- liveness + row limit ----
[Fact]
@@ -69,13 +69,43 @@ public class PostgresDialectTests
// NAMEDATALEN - 1: a longer string cannot name a real Postgres object (the server truncates it), so it
// is a config mistake rather than something to quote and send.
[Fact]
public void QuoteIdentifier_acceptsExactly63Chars_andRejects64()
public void QuoteIdentifier_acceptsExactly63Bytes_andRejects64()
{
var d = new PostgresDialect();
d.QuoteIdentifier(new string('a', 63)).ShouldBe("\"" + new string('a', 63) + "\"");
Should.Throw<ArgumentException>(() => d.QuoteIdentifier(new string('a', 64)));
}
/// <summary>
/// <c>NAMEDATALEN - 1</c> is 63 <b>bytes in the database encoding</b>, not 63 characters — so a
/// 32-character Cyrillic name is 64 UTF-8 bytes and the server truncates it to something that names a
/// different object. A ceiling measured in UTF-16 code units lets that name straight through, which
/// is precisely the silent-truncation failure this rule documents itself as preventing.
/// </summary>
[Fact]
public void QuoteIdentifier_measuresTheCeilingInUtf8Bytes_notCharacters()
{
var d = new PostgresDialect();
// 31 Cyrillic characters = 62 UTF-8 bytes — inside the limit, and well inside a character count.
d.QuoteIdentifier(new string('б', 31)).ShouldBe("\"" + new string('б', 31) + "\"");
// 32 characters = 64 bytes. Under a character-counting ceiling this passes; the server truncates it.
Should.Throw<ArgumentException>(() => d.QuoteIdentifier(new string('б', 32)));
}
/// <summary>A non-BMP character is 4 UTF-8 bytes (and 2 UTF-16 code units) — 16 of them fill the limit.</summary>
[Fact]
public void QuoteIdentifier_countsASupplementaryCharacterAsItsFourUtf8Bytes()
{
var d = new PostgresDialect();
// U+1D400 MATHEMATICAL BOLD CAPITAL A, as a surrogate pair.
const string a = "\U0001D400";
d.QuoteIdentifier(string.Concat(Enumerable.Repeat(a, 15))).ShouldNotBeNullOrEmpty(); // 60 bytes
Should.Throw<ArgumentException>(
() => d.QuoteIdentifier(string.Concat(Enumerable.Repeat(a, 16)))); // 64 bytes
}
[Fact]
public void QuoteIdentifier_neutralisesAClassicInjectionPayload()
{
@@ -189,6 +219,15 @@ public class PostgresDialectTests
.ShouldBe("SELECT \"a\" LIMIT 1");
}
/// <summary>
/// 65535 — the <c>Bind</c> message's 16-bit parameter count, a protocol ceiling rather than a server
/// setting. Pinned so the planner's chunking has a real number here instead of a special case for
/// "this dialect has no meaningful limit".
/// </summary>
[Fact]
public void MaxBindParameters_isTheWireProtocolsSixteenBitCount()
=> new PostgresDialect().MaxBindParameters.ShouldBe(65535);
[Fact]
public void Dialect_identifiesItselfAsPostgres_andExposesTheAbstractFactory()
{
@@ -105,6 +105,8 @@ public sealed class SqlCatalogDefaultSchemaTests
public DbProviderFactory Factory => Inner.Factory;
public int MaxBindParameters => Inner.MaxBindParameters;
public string LivenessSql => Inner.LivenessSql;
public string SingleRowLimitPrefix => Inner.SingleRowLimitPrefix;
@@ -337,6 +337,8 @@ public sealed class SqlCatalogGateDriverTests
public System.Data.Common.DbProviderFactory Factory => Inner.Factory;
public int MaxBindParameters => Inner.MaxBindParameters;
public string LivenessSql => Inner.LivenessSql;
public string SingleRowLimitPrefix => Inner.SingleRowLimitPrefix;
@@ -0,0 +1,318 @@
using System.Data.Common;
using System.Globalization;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using ZB.MOM.WW.OtOpcUa.Driver.Sql.Contracts;
namespace ZB.MOM.WW.OtOpcUa.Driver.Sql.Tests;
/// <summary>
/// Pins the bind-parameter ceiling (Driver.Sql-002 / Driver.Sql.Dialect-002): a key-value group holding
/// more distinct <c>keyValue</c>s than the dialect's <see cref="ISqlDialect.MaxBindParameters"/> is split
/// into several plans over the <b>same</b> group key, rather than emitting one statement the provider
/// rejects.
/// <para><b>Why this is a correctness test and not a tuning one.</b> Over the ceiling the provider refuses
/// the statement <em>after</em> the connection opened, so every tag in the group publishes
/// <c>BadCommunicationError</c> on every poll, permanently — and a key-value (EAV) staging table is
/// precisely the shape that attracts thousands of tags on one table, which the group-key rule folds into
/// one group.</para>
/// <para>A single group emitting several plans needs <b>no reader change</b>: <c>SqlPollReader</c> runs
/// one command per plan and slices each plan's own <c>Members</c> back, so the last test here drives the
/// whole read path over a real database to prove exactly that.</para>
/// </summary>
public sealed class SqlGroupPlannerChunkingTests
{
private static SqlTagDefinition KvTag(string name, string keyValue, string table = "dbo.TagValues")
=> new(name, SqlTagModel.KeyValue, table,
KeyColumn: "tag_name", KeyValue: keyValue, ValueColumn: "num_value");
// ---- the shipped ceilings ----
/// <summary>
/// Oracle's real ceiling, on the real dialect: an <c>IN</c> expression list may hold 1000 entries, so
/// 1001 distinct keys cannot be one statement. This is the shape the finding describes — no test-only
/// dialect involved.
/// </summary>
[Fact]
public void AGroupBeyondTheOracleInListLimit_isSplit_ratherThanEmittedAsOneRejectedStatement()
{
var dialect = new OracleDialect();
var tags = Enumerable.Range(0, 1001)
.Select(i => KvTag("T" + i.ToString(CultureInfo.InvariantCulture),
"Key" + i.ToString(CultureInfo.InvariantCulture)))
.ToArray();
var plans = SqlGroupPlanner.Plan(tags, dialect);
plans.Count.ShouldBe(2);
plans.ShouldAllBe(p => p.Parameters.Count <= 1000);
plans.Sum(p => p.Parameters.Count).ShouldBe(1001);
}
/// <summary>
/// The same for SQL Server, whose 2100-parameter command cap is the other limit the finding names.
/// </summary>
[Fact]
public void AGroupBeyondTheSqlServerParameterCap_isSplit()
{
var dialect = new SqlServerDialect();
var tags = Enumerable.Range(0, dialect.MaxBindParameters + 1)
.Select(i => KvTag("T" + i.ToString(CultureInfo.InvariantCulture),
"Key" + i.ToString(CultureInfo.InvariantCulture)))
.ToArray();
var plans = SqlGroupPlanner.Plan(tags, dialect);
plans.Count.ShouldBe(2);
plans.ShouldAllBe(p => p.Parameters.Count <= dialect.MaxBindParameters);
}
// ---- how a split group is shaped ----
[Fact]
public void EachChunkBindsAtMostTheCeiling_andTheChunksCoverEveryKeyExactlyOnce()
{
var tags = Enumerable.Range(0, 7)
.Select(i => KvTag("T" + i.ToString(CultureInfo.InvariantCulture),
"Key" + i.ToString(CultureInfo.InvariantCulture)))
.ToArray();
var plans = SqlGroupPlanner.Plan(tags, new BindCeilingDialect(3));
plans.Count.ShouldBe(3);
plans.Select(p => p.Parameters.Count).ShouldBe(new[] { 3, 3, 1 });
plans.SelectMany(p => p.Parameters)
.ShouldBe(Enumerable.Range(0, 7).Select(i => (object?)("Key" + i.ToString(CultureInfo.InvariantCulture))));
}
/// <summary>
/// Every member must land in the chunk that binds <em>its own</em> key — a member whose key is bound
/// by a different plan reads a result set that cannot contain its row and publishes
/// <c>BadNoData</c> forever, which is the quiet way to get this wrong.
/// </summary>
[Fact]
public void EveryMemberLandsInTheChunkThatBindsItsOwnKey()
{
var tags = Enumerable.Range(0, 7)
.Select(i => KvTag("T" + i.ToString(CultureInfo.InvariantCulture),
"Key" + i.ToString(CultureInfo.InvariantCulture)))
.ToArray();
var plans = SqlGroupPlanner.Plan(tags, new BindCeilingDialect(3));
foreach (var plan in plans)
foreach (var member in plan.Members)
plan.Parameters.ShouldContain(member.KeyValue);
// …and no member is dropped or duplicated across the split.
plans.SelectMany(p => p.Members).Select(m => m.Name)
.ShouldBe(tags.Select(t => t.Name), ignoreOrder: true);
plans.Sum(p => p.Members.Count).ShouldBe(tags.Length);
}
/// <summary>
/// Two tags on one <c>keyValue</c> bind one parameter and must stay in one chunk — splitting them
/// would bind the same key twice and cost a whole extra round-trip for a row already fetched.
/// </summary>
[Fact]
public void MembersSharingAKeyValue_stayInTheSameChunk()
{
var plans = SqlGroupPlanner.Plan(
[
KvTag("A", "K1"), KvTag("B", "K2"), KvTag("C", "K1"), KvTag("D", "K3"),
], new BindCeilingDialect(2));
plans.Count.ShouldBe(2);
plans[0].Parameters.ShouldBe(new object[] { "K1", "K2" });
plans[0].Members.Select(m => m.Name).ShouldBe(new[] { "A", "B", "C" });
plans[1].Parameters.ShouldBe(new object[] { "K3" });
plans[1].Members.Select(m => m.Name).ShouldBe(new[] { "D" });
}
/// <summary>
/// Each chunk is its own command, so its markers restart at <c>k0</c> — carrying the global index
/// forward would emit <c>IN (@k3, @k4, @k5)</c> against a three-parameter command, which is legal but
/// makes a plan's SQL unreadable next to its own parameter list.
/// </summary>
[Fact]
public void EachChunkNumbersItsMarkersFromZero_andTheSqlMatchesItsOwnParameters()
{
var tags = Enumerable.Range(0, 5)
.Select(i => KvTag("T" + i.ToString(CultureInfo.InvariantCulture),
"Key" + i.ToString(CultureInfo.InvariantCulture)))
.ToArray();
var plans = SqlGroupPlanner.Plan(tags, new BindCeilingDialect(2));
foreach (var plan in plans)
{
plan.ParameterNames.ShouldBe(
Enumerable.Range(0, plan.Parameters.Count)
.Select(i => "@k" + i.ToString(CultureInfo.InvariantCulture)));
plan.SqlText.ShouldEndWith("IN (" + string.Join(", ", plan.ParameterNames) + ")");
}
}
/// <summary>All chunks of one group carry that group's key — the split is an execution detail, not a regrouping.</summary>
[Fact]
public void EveryChunkOfOneGroupCarriesTheSameGroupKey()
{
var tags = Enumerable.Range(0, 5)
.Select(i => KvTag("T" + i.ToString(CultureInfo.InvariantCulture),
"Key" + i.ToString(CultureInfo.InvariantCulture)))
.ToArray();
var plans = SqlGroupPlanner.Plan(tags, new BindCeilingDialect(2));
plans.Count.ShouldBeGreaterThan(1);
plans.Select(p => p.GroupKey).Distinct().Count().ShouldBe(1);
}
/// <summary>
/// The falsifiability control. Chunking must not fragment an ordinary group: a planner that split
/// eagerly (or off a stale count) would pass every test above and quietly turn one round-trip per
/// source into N.
/// </summary>
[Theory]
[InlineData(1)]
[InlineData(2)]
[InlineData(3)]
public void AGroupAtOrUnderTheCeiling_stillEmitsExactlyOnePlan(int distinctKeys)
{
var tags = Enumerable.Range(0, distinctKeys)
.Select(i => KvTag("T" + i.ToString(CultureInfo.InvariantCulture),
"Key" + i.ToString(CultureInfo.InvariantCulture)))
.ToArray();
var plans = SqlGroupPlanner.Plan(tags, new BindCeilingDialect(3));
plans.Count.ShouldBe(1);
plans[0].Members.Count.ShouldBe(distinctKeys);
}
/// <summary>
/// Two groups that each need splitting stay separate, and the chunks of one never mix with the other's
/// — the split happens inside a group, after grouping.
/// </summary>
[Fact]
public void TwoOversizedGroups_areSplitIndependently()
{
var tags = Enumerable.Range(0, 3).Select(i => KvTag("A" + i, "K" + i, "dbo.First"))
.Concat(Enumerable.Range(0, 3).Select(i => KvTag("B" + i, "K" + i, "dbo.Second")))
.ToArray();
var plans = SqlGroupPlanner.Plan(tags, new BindCeilingDialect(2));
plans.Count.ShouldBe(4);
// Group order still follows the input order of each group's first member (dbo.First, then dbo.Second),
// and a group's own chunks stay adjacent and in key order.
plans.Select(p => p.Members[0].Table).ShouldBe(["dbo.First", "dbo.First", "dbo.Second", "dbo.Second"]);
}
/// <summary>A wide-row plan binds at most one value, so a ceiling of 1 must not disturb it.</summary>
[Fact]
public void AWideRowPlan_isUnaffectedByTheCeiling()
{
var tag = new SqlTagDefinition("A", SqlTagModel.WideRow, "dbo.LatestStatus",
ColumnName: "oven_temp", RowSelectorColumn: "station_id", RowSelectorValue: "7");
var plans = SqlGroupPlanner.Plan([tag], new BindCeilingDialect(1));
plans.Count.ShouldBe(1);
plans[0].Parameters.Count.ShouldBe(1);
}
/// <summary>
/// A dialect reporting a ceiling below 1 cannot be chunked to — it must fail loudly rather than loop
/// forever or emit an empty <c>IN ()</c> list, which is a syntax error on every backend.
/// </summary>
[Theory]
[InlineData(0)]
[InlineData(-1)]
public void ADialectReportingANonPositiveCeiling_isRejected(int ceiling)
=> Should.Throw<ArgumentException>(
() => SqlGroupPlanner.Plan([KvTag("A", "K1")], new BindCeilingDialect(ceiling)));
// ---- the whole read path, over a real database ----
/// <summary>
/// Drives <see cref="SqlPollReader"/> over the SQLite fixture with a ceiling of 1, so three keys become
/// three plans, and asserts every tag still reads its own value. This is what proves several plans per
/// group need <b>no reader change</b> — the claim the chunking design rests on.
/// </summary>
[Fact]
public async Task ThePollReader_readsEveryTagCorrectly_whenOneGroupIsSplitAcrossSeveralPlans()
{
using var fixture = new SqlitePollFixture();
SqlTagDefinition[] tags =
[
Fixture("Speed", SqlitePollFixture.PresentKey),
Fixture("Pressure", SqlitePollFixture.SecondPresentKey),
Fixture("Missing", SqlitePollFixture.AbsentKey),
];
var reader = new SqlPollReader(
fixture.Factory, fixture.ConnectionString, new BindCeilingDialect(1),
commandTimeout: TimeSpan.FromSeconds(10), operationTimeout: TimeSpan.FromSeconds(15),
maxConcurrentGroups: 4, nullIsBad: false,
resolve: reference => tags.FirstOrDefault(t => t.Name == reference));
var snapshots = await reader.ReadAsync(["Speed", "Pressure", "Missing"], CancellationToken.None);
snapshots[0].Value.ShouldBe(SqlitePollFixture.PresentValue);
snapshots[0].StatusCode.ShouldBe(SqlStatusCodes.Good);
snapshots[1].Value.ShouldBe(SqlitePollFixture.SecondPresentValue);
snapshots[1].StatusCode.ShouldBe(SqlStatusCodes.Good);
snapshots[2].StatusCode.ShouldBe(SqlStatusCodes.BadNoData);
}
private static SqlTagDefinition Fixture(string name, string keyValue)
=> new(name, SqlTagModel.KeyValue, SqlitePollFixture.KeyValueTable,
KeyColumn: SqlitePollFixture.KeyColumn, KeyValue: keyValue,
ValueColumn: SqlitePollFixture.ValueColumn,
TimestampColumn: SqlitePollFixture.TimestampColumn);
/// <summary>
/// A <b>test-only</b> dialect that reports a caller-chosen <see cref="ISqlDialect.MaxBindParameters"/>
/// and delegates everything else to <see cref="SqliteDialect"/> — so a chunked plan can be asserted on
/// at a readable size <em>and</em> actually executed against the fixture database.
/// <para>A decorator rather than a subclass, for the reason the other fakes here give:
/// <see cref="SqliteDialect"/> is sealed, and <c>new</c>-hiding a member would leave interface dispatch
/// calling the original, so the substitution would silently not happen.</para>
/// </summary>
private sealed class BindCeilingDialect(int maxBindParameters) : ISqlDialect
{
private static readonly SqliteDialect Inner = new();
public int MaxBindParameters { get; } = maxBindParameters;
public SqlProvider Provider => Inner.Provider;
public DbProviderFactory Factory => Inner.Factory;
public string LivenessSql => Inner.LivenessSql;
public string SingleRowLimitPrefix => Inner.SingleRowLimitPrefix;
public string SingleRowLimitSuffix => Inner.SingleRowLimitSuffix;
public string ListSchemasSql => Inner.ListSchemasSql;
public string DefaultSchemaSql => Inner.DefaultSchemaSql;
public string ListTablesSql => Inner.ListTablesSql;
public string ListColumnsSql => Inner.ListColumnsSql;
public string ParameterMarker(string baseName) => Inner.ParameterMarker(baseName);
public string ParameterBindName(string baseName) => Inner.ParameterBindName(baseName);
public void ConfigureCommand(DbCommand command) => Inner.ConfigureCommand(command);
public string QuoteIdentifier(string ident) => Inner.QuoteIdentifier(ident);
public DriverDataType MapColumnType(string sqlDataType) => Inner.MapColumnType(sqlDataType);
}
}
@@ -84,6 +84,18 @@ public class SqlServerDialectTests
.ShouldBe("SELECT TOP 1 [a]");
}
/// <summary>
/// 2098, not 2100: <c>Microsoft.Data.SqlClient</c> routes a parameterized command through
/// <c>sp_executesql</c>, whose statement text and parameter-declaration arguments consume two of the
/// server's 2100. A ceiling of 2100 would be rejected by a caller that filled it exactly.
/// </summary>
[Fact]
public void MaxBindParameters_leavesRoomForSpExecutesqlsOwnTwoParameters()
{
new SqlServerDialect().MaxBindParameters.ShouldBe(2098);
new SqlServerDialect().MaxBindParameters.ShouldBeLessThan(2100);
}
// ---- extra guards on the injection boundary (beyond the plan's golden set) ----
[Fact]
@@ -117,6 +129,19 @@ public class SqlServerDialectTests
Should.Throw<ArgumentException>(() => d.QuoteIdentifier(new string('a', 129)));
}
/// <summary>
/// The falsifiability control for the Postgres/Oracle byte ceilings: T-SQL's <c>sysname</c> is
/// <c>nvarchar(128)</c>, a genuine <b>128-character</b> (UTF-16 code unit) limit, so a 128-character
/// Cyrillic name — 256 UTF-8 bytes — is legal here and must still be accepted. A byte rule applied
/// uniformly across the three dialects would reject it, and only this test would say so.
/// </summary>
[Fact]
public void QuoteIdentifier_countsCharacters_notBytes_becauseSysnameIsNvarchar128()
{
var ident = new string('б', 128); // 128 chars, 256 UTF-8 bytes
new SqlServerDialect().QuoteIdentifier(ident).ShouldBe("[" + ident + "]");
}
[Fact]
public void QuoteIdentifier_neutralisesAClassicInjectionPayload()
{
@@ -64,6 +64,13 @@ public sealed class SqliteDialect : ISqlDialect
// Intentionally empty: see the summary.
}
/// <summary>
/// 999 — <c>SQLITE_MAX_VARIABLE_NUMBER</c>'s historical default, and still the safe floor: SQLite
/// raised it to 32766 in 3.32, but the value is a compile-time setting of whatever native library the
/// bundle happens to carry, so the lower number is the one that always executes.
/// </summary>
public int MaxBindParameters => 999;
/// <inheritdoc/>
public string LivenessSql => "SELECT 1";