feat(qwp): schema aware clients

README.md

@@ -555,7 +555,9 @@ Applied by the query pool to select and fail over between the nodes in the `addr
 | `client_id` |         | Opaque client identifier surfaced server-side for observability                          |
 
 The ingest side also accepts store-and-forward and reconnection tuning keys (`auto_flush_*`, `initial_connect_retry`,
-`reconnect_*`, `request_durable_ack`, `sf_*`, `max_frame_rejections`, `poison_min_escalation_window_millis`, …).
+`reconnect_*`, `request_durable_ack`, `sf_*`, `max_frame_rejections`, `poison_min_escalation_window_millis`, …) and
+the schema-aware keys `schema_mode` (`auto`, `strict`, `off`) and `schema_wait_millis`; see
+[docs/schema-aware-ingestion.md](docs/schema-aware-ingestion.md).
 `sf_durability=periodic` checkpoints mmap-published data in the background; `sf_sync_interval_millis` defaults to `5000`
 in that mode. The interval is a target cadence: JVM scheduling and storage-sync latency add to the actual loss window.
 Use `request_durable_ack=on` when end-to-end server durability is also required. See the

core/pom.xml

@@ -194,7 +194,7 @@
                     </excludes>
                 </configuration>
             </plugin>
-            <!-- Packaging integration tests (JarPackagingIT): the sun.misc.FDBigInteger /
+            <!-- Packaging integration tests (JarPackagingIT): the versioned-shim /
                  module-name regressions in 1.3.5-1.3.7 were invisible to unit tests because
                  they run against target/classes, where Multi-Release selection never
                  happens. These ITs inspect and execute the packaged jar itself. -->
@@ -220,7 +220,7 @@
                 </configuration>
             </plugin>
             <!-- Adds the JDK-version-specific source root (src/main/java11 or src/main/java8)
-                 so the FDBigInteger bridge / module-access shim compiles on each JDK. -->
+                 so the Compat shim compiles on each JDK. -->
             <plugin>
                 <groupId>org.codehaus.mojo</groupId>
                 <artifactId>build-helper-maven-plugin</artifactId>
@@ -440,8 +440,8 @@
             <build>
                 <plugins>
                     <!-- The shipped artifact must be the JDK 8 build: a JDK 11+ build puts the
-                         jdk.internal.math FdBig bridge and module-info.class into the jar ROOT,
-                         which breaks Java 8 consumers. Refuse to publish from any other JDK. -->
+                         Java 9+ Compat shim and module-info.class into the jar ROOT, which
+                         breaks Java 8 consumers. Refuse to publish from any other JDK. -->
                     <plugin>
                         <groupId>org.apache.maven.plugins</groupId>
                         <artifactId>maven-enforcer-plugin</artifactId>
@@ -561,13 +561,13 @@
             </activation>
             <build>
                 <plugins>
-                    <!-- JDK 8 javac can only compile the src/main/java8 FdBig bridge
-                         (sun.misc.FDBigInteger), which does not exist on Java 9+. Package the
-                         src/main/java11 bridge (jdk.internal.math.FDBigInteger) into
-                         META-INF/versions/11 so the Multi-Release jar works on every JDK.
-                         Shipping a JDK 8-built jar without this breaks double formatting on
-                         Java 9+ with NoClassDefFoundError (the 1.3.5-1.3.7 regression), hence
-                         a missing JDK 11 fails the build instead of skipping. -->
+                    <!-- JDK 8 javac can only compile the src/main/java8 Compat shim, whose
+                         multiplyHigh/onSpinWait fallbacks exist only for Java 8. Package the
+                         src/main/java11 shim, which uses the Math.multiplyHigh and
+                         Thread.onSpinWait intrinsics, into META-INF/versions/11 so the
+                         Multi-Release jar picks the right variant on every JDK. The Ryu double
+                         formatter calls multiplyHigh on every value, so a missing JDK 11 fails
+                         the build instead of skipping. -->
                     <plugin>
                         <groupId>org.apache.maven.plugins</groupId>
                         <artifactId>maven-antrun-plugin</artifactId>

core/src/main/java/io/questdb/client/LineSenderSchemaException.java

@@ -0,0 +1,47 @@
+/*+*****************************************************************************
+ *     ___                  _   ____  ____
+ *    / _ \ _   _  ___  ___| |_|  _ \| __ )
+ *   | | | | | | |/ _ \/ __| __| | | |  _ \
+ *   | |_| | |_| |  __/\__ \ |_| |_| | |_) |
+ *    \__\_\\__,_|\___||___/\__|____/|____/
+ *
+ * Copyright (c) 2014-2019 Appsicle
+ * Copyright (c) 2019-2026 QuestDB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ ******************************************************************************/
+
+package io.questdb.client;
+
+import io.questdb.client.cutlass.line.LineSenderException;
+
+/** A schema-bound row construction failure with a stable reason. */
+public class LineSenderSchemaException extends LineSenderException {
+    public enum Reason {
+        INVALID_VALUE,
+        SCHEMA_UNAVAILABLE,
+        ACCESS_DENIED,
+        UNSUPPORTED_FEATURE
+    }
+
+    private final Reason reason;
+
+    public LineSenderSchemaException(Reason reason, CharSequence message) {
+        super(message, false);
+        this.reason = reason;
+    }
+
+    public Reason getReason() {
+        return reason;
+    }
+}