Feature/249 evaluate expected resultset datatype (#250)

* #249 implemented remaining questions: see ticket #249 Co-authored-by: Christoph Pirkl <[email protected]>
exasol · Sep 9, 2022 · 332f400 · 332f400
1 parent db92c56
commit 332f400
Show file tree

Hide file tree

Showing 26 changed files with 870 additions and 160 deletions.
diff --git a/.gitattributes b/.gitattributes
@@ -0,0 +1,11 @@
+dependencies.md                                                  linguist-generated=true
+doc/changes/changelog.md                                         linguist-generated=true
+pk_generated_parent.pom                                          linguist-generated=true
+.github/workflows/broken_links_checker.yml                       linguist-generated=true
+.github/workflows/ci-build-next-java.yml			 linguist-generated=true
+.github/workflows/ci-build.yml					 linguist-generated=true
+.github/workflows/dependencies_check.yml			 linguist-generated=true
+.github/workflows/release_droid_prepare_original_checksum.yml	 linguist-generated=true
+.github/workflows/release_droid_print_quick_checksum.yml	 linguist-generated=true
+.github/workflows/release_droid_release_on_maven_central.yml	 linguist-generated=true
+.github/workflows/release_droid_upload_github_release_assets.yml linguist-generated=true
diff --git a/.github/workflows/release_droid_upload_github_release_assets.yml b/.github/workflows/release_droid_upload_github_release_assets.yml
diff --git a/.gitignore b/.gitignore
@@ -30,4 +30,6 @@ venv/
 *.orig
 *.old
 *.md.html
-*.flattened-pom.xml
+*.flattened-pom.xml
+/.apt_generated/
+/.apt_generated_tests/
diff --git a/README.md b/README.md
@@ -19,8 +19,6 @@ This is one of the modules of Virtual Schemas Adapters. The libraries provided b
 
 A Virtual Schema adapter is basically a [UDF](https://docs.exasol.com/database_concepts/udf_scripts.htm). The Exasol core database communicates with this UDF using JSON strings. There are different types of messages, that define the API for a virtual Schema adapter ([protocol reference](doc/development/api/virtual_schema_api.md)). This repository wraps this JSON API with a Java API to facilitate the implementation of Virtual Schema adapters in Java.
 
-Please note that the artifact name changed from "virtualschema-common" to "virtual-schema-common-java". First to unify the naming schemes, second to make sure the new adapters do not accidentally use the old line of libraries.
-
 ## Information for Users
 
 * [Changelog](doc/changes/changelog.md)

diff --git a/dependencies.md b/dependencies.md
diff --git a/doc/changes/changelog.md b/doc/changes/changelog.md
diff --git a/doc/changes/changes_16.0.0.md b/doc/changes/changes_16.0.0.md
@@ -0,0 +1,25 @@
+# Common module of Exasol Virtual Schemas Adapters 16.0.0, released 2022-??-??
+
+Code name: Evaluate expected resultset datatypes
+
+## Summary
+
+Starting with major version 8 Exasol database uses the capabilities reported by each virtual schema to provide select list data types for each push down request. Based on this information the JDBC virtual schemas no longer need to infer the data types of the result set by inspecting its values. Instead the JDBC virtual schemas can now use the information provided by the database.
+
+This create a list of benefits
+* Improved performance of queries to virtual schema by avoiding one query for each push down
+* Enhanced accuracy of data type mapping
+* Simplified data type mapping which is easier to extend
+* Support for additional use cases
+
+## Features
+
+* #249: Evaluate expected resultset datatypes
+
+## Dependency Updates
+
+### Plugin Dependency Updates
+
+* Updated `com.exasol:error-code-crawler-maven-plugin:1.1.1` to `1.1.2`
+* Updated `com.exasol:project-keeper-maven-plugin:2.5.0` to `2.7.0`
+* Updated `org.apache.maven.plugins:maven-enforcer-plugin:3.0.0` to `3.1.0`
diff --git a/error_code_config.yml b/error_code_config.yml
@@ -2,4 +2,4 @@ error-tags:
   VSCOMJAVA:
     packages:
       - com.exasol
-    highest-index: 35
+    highest-index: 40
diff --git a/pk_generated_parent.pom b/pk_generated_parent.pom
diff --git a/pom.xml b/pom.xml
@@ -1,9 +1,8 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
-    <groupId>com.exasol</groupId>
     <artifactId>virtual-schema-common-java</artifactId>
-    <version>15.3.3</version>
+    <version>16.0.0</version>
     <name>Common module of Exasol Virtual Schemas Adapters</name>
     <description>This is one of the modules of Virtual Schemas Adapters. The libraries provided by this project are the
         foundation of the adapter development, i.e. adapters must be implemented on top of them.</description>
@@ -89,7 +88,7 @@
             <plugin>
                 <groupId>com.exasol</groupId>
                 <artifactId>project-keeper-maven-plugin</artifactId>
-                <version>2.5.0</version>
+                <version>2.7.0</version>
                 <executions>
                     <execution>
                         <goals>
@@ -103,7 +102,7 @@
     <parent>
         <artifactId>virtual-schema-common-java-generated-parent</artifactId>
         <groupId>com.exasol</groupId>
-        <version>15.3.3</version>
+        <version>16.0.0</version>
         <relativePath>pk_generated_parent.pom</relativePath>
     </parent>
 </project>
diff --git a/src/main/java/com/exasol/adapter/request/PushDownRequest.java b/src/main/java/com/exasol/adapter/request/PushDownRequest.java
@@ -5,34 +5,36 @@
 import com.exasol.ExaMetadata;
 import com.exasol.adapter.AdapterCallExecutor;
 import com.exasol.adapter.AdapterException;
-import com.exasol.adapter.metadata.SchemaMetadataInfo;
-import com.exasol.adapter.metadata.TableMetadata;
+import com.exasol.adapter.metadata.*;
 import com.exasol.adapter.sql.SqlStatement;
 
 /**
  * This class represents a request that tells a Virtual Schema Adapter to push a SQL statement down to the external data
- * source
+ * source.
  */
 public class PushDownRequest extends AbstractAdapterRequest {
     private final SqlStatement select;
     private final List<TableMetadata> involvedTablesMetadata;
+    private final List<DataType> selectListDataTypes;
 
     /**
-     * Create a new request of type {@link PushDownRequest}
+     * Create a new request of type {@link PushDownRequest}.
      *
      * @param schemaMetadataInfo     schema metadata
      * @param select                 SQL statement to be pushed down to the external data source
      * @param involvedTablesMetadata tables involved in the push-down request
+     * @param selectListDataType     expected data types for the result set
      */
     public PushDownRequest(final SchemaMetadataInfo schemaMetadataInfo, final SqlStatement select,
-            final List<TableMetadata> involvedTablesMetadata) {
+            final List<TableMetadata> involvedTablesMetadata, final List<DataType> selectListDataType) {
         super(schemaMetadataInfo, AdapterRequestType.PUSHDOWN);
         this.select = select;
         this.involvedTablesMetadata = involvedTablesMetadata;
+        this.selectListDataTypes = selectListDataType;
     }
 
     /**
-     * Get the <code>SELECT</code> statement that should be pushed down to the external data source
+     * Get the <code>SELECT</code> statement that should be pushed down to the external data source.
      *
      * @return <code>SELECT</code> statement
      */
@@ -49,6 +51,15 @@ public List<TableMetadata> getInvolvedTablesMetadata() {
         return this.involvedTablesMetadata;
     }
 
+    /**
+     * Get the expected data types for the result set.
+     *
+     * @return expected data types for the result set
+     */
+    public List<DataType> getSelectListDataTypes() {
+        return this.selectListDataTypes;
+    }
+
     @Override
     public String executeWith(final AdapterCallExecutor adapterCallExecutor, final ExaMetadata metadata)
             throws AdapterException {

diff --git a/src/main/java/com/exasol/adapter/request/parser/AbstractRequestParser.java b/src/main/java/com/exasol/adapter/request/parser/AbstractRequestParser.java
@@ -6,7 +6,6 @@
 import java.nio.charset.StandardCharsets;
 import java.util.*;
 import java.util.Map.Entry;
-import java.util.logging.Logger;
 
 import com.exasol.errorreporting.ExaError;
 
@@ -17,7 +16,6 @@
  * Abstract base class for parsers reading fragments of the Virtual Schema requests.
  */
 class AbstractRequestParser {
-    private static final Logger LOGGER = Logger.getLogger(AbstractRequestParser.class.getName());
 
     /**
      * Create a JSON reader for raw request data.
@@ -36,7 +34,7 @@ protected JsonReader createJsonReader(final String rawRequest) {
 
     /**
      * Read the properties from the schema metadata.
-     * 
+     *
      * @param jsonSchemaMetadataInfo json schema metadata info
      * @return parsed Properties.
      */
@@ -85,7 +83,6 @@ private void addProperty(final Map<String, String> properties, final Entry<Strin
                             + "Supported types are strings, booleans, numbers and NULL.")
                     .parameter("type", type).toString());
         }
-        LOGGER.finer(() -> "Parsed property: \"" + key + "\" = \"" + stringValue + "\"");
         properties.put(key, stringValue);
     }
 }