refine table source for regexp tree dictionary

src/Dictionaries/ClickHouseDictionarySource.cpp

@@ -71,11 +71,11 @@ ClickHouseDictionarySource::ClickHouseDictionarySource(
     : update_time{std::chrono::system_clock::from_time_t(0)}
     , dict_struct{dict_struct_}
     , configuration{configuration_}
-    , query_builder{dict_struct, configuration.db, "", configuration.table, configuration.query, configuration.where, IdentifierQuotingStyle::Backticks}
+    , query_builder(std::make_shared<ExternalQueryBuilder>(dict_struct, configuration.db, "", configuration.table, configuration.query, configuration.where, IdentifierQuotingStyle::Backticks))
     , sample_block{sample_block_}
     , context(context_)
     , pool{createPool(configuration)}
-    , load_all_query{query_builder.composeLoadAllQuery()}
+    , load_all_query{query_builder->composeLoadAllQuery()}
 {
 }
 
@@ -84,7 +84,7 @@ ClickHouseDictionarySource::ClickHouseDictionarySource(const ClickHouseDictionar
     , dict_struct{other.dict_struct}
     , configuration{other.configuration}
     , invalidate_query_response{other.invalidate_query_response}
-    , query_builder{dict_struct, configuration.db, "", configuration.table, configuration.query, configuration.where, IdentifierQuotingStyle::Backticks}
+    , query_builder(std::make_shared<ExternalQueryBuilder>(dict_struct, configuration.db, "", configuration.table, configuration.query, configuration.where, IdentifierQuotingStyle::Backticks))
     , sample_block{other.sample_block}
     , context(Context::createCopy(other.context))
     , pool{createPool(configuration)}
@@ -99,12 +99,12 @@ std::string ClickHouseDictionarySource::getUpdateFieldAndDate()
         time_t hr_time = std::chrono::system_clock::to_time_t(update_time) - configuration.update_lag;
         std::string str_time = DateLUT::instance().timeToString(hr_time);
         update_time = std::chrono::system_clock::now();
-        return query_builder.composeUpdateQuery(configuration.update_field, str_time);
+        return query_builder->composeUpdateQuery(configuration.update_field, str_time);
     }
     else
     {
         update_time = std::chrono::system_clock::now();
-        return query_builder.composeLoadAllQuery();
+        return query_builder->composeLoadAllQuery();
     }
 }
 
@@ -121,13 +121,13 @@ QueryPipeline ClickHouseDictionarySource::loadUpdatedAll()
 
 QueryPipeline ClickHouseDictionarySource::loadIds(const std::vector<UInt64> & ids)
 {
-    return createStreamForQuery(query_builder.composeLoadIdsQuery(ids));
+    return createStreamForQuery(query_builder->composeLoadIdsQuery(ids));
 }
 
 
 QueryPipeline ClickHouseDictionarySource::loadKeys(const Columns & key_columns, const std::vector<size_t> & requested_rows)
 {
-    String query = query_builder.composeLoadKeysQuery(key_columns, requested_rows, ExternalQueryBuilder::IN_WITH_TUPLES);
+    String query = query_builder->composeLoadKeysQuery(key_columns, requested_rows, ExternalQueryBuilder::IN_WITH_TUPLES);
     return createStreamForQuery(query);
 }
 

src/Dictionaries/ClickHouseDictionarySource.h

@@ -78,11 +78,11 @@ private:
     const DictionaryStructure dict_struct;
     const Configuration configuration;
     mutable std::string invalidate_query_response;
-    ExternalQueryBuilder query_builder;
+    ExternalQueryBuilderPtr query_builder;
     Block sample_block;
     ContextMutablePtr context;
     ConnectionPoolWithFailoverPtr pool;
-    const std::string load_all_query;
+    std::string load_all_query;
     Poco::Logger * log = &Poco::Logger::get("ClickHouseDictionarySource");
 
     /// RegExpTreeDictionary is the only dictionary whose structure of attributions differ from the input block.

src/Dictionaries/ExternalQueryBuilder.h

@@ -36,6 +36,10 @@ struct ExternalQueryBuilder
         const std::string & where_,
         IdentifierQuotingStyle quoting_style_);
 
+    ExternalQueryBuilder(const ExternalQueryBuilder &) = default;
+
+    virtual ~ExternalQueryBuilder() = default;
+
     /** Generate a query to load all data. */
     std::string composeLoadAllQuery() const;
 
@@ -61,10 +65,10 @@ struct ExternalQueryBuilder
     std::string composeLoadKeysQuery(const Columns & key_columns, const std::vector<size_t> & requested_rows, LoadKeysMethod method, size_t partition_key_prefix = 0) const;
 
 
-private:
+protected:
     const FormatSettings format_settings = {};
 
-    void composeLoadAllQuery(WriteBuffer & out) const;
+    virtual void composeLoadAllQuery(WriteBuffer & out) const;
 
     /// In the following methods `beg` and `end` specifies which columns to write in expression
 
@@ -93,4 +97,6 @@ private:
     void writeQuoted(const std::string & s, WriteBuffer & out) const;
 };
 
+using ExternalQueryBuilderPtr = std::shared_ptr<ExternalQueryBuilder>;
+
 }

src/Dictionaries/RegExpTreeDictionary.cpp

@@ -20,6 +20,7 @@
 #include <Functions/Regexps.h>
 #include <Functions/checkHyperscanRegexp.h>
 #include <QueryPipeline/QueryPipeline.h>
+#include <Processors/Sources/BlocksListSource.h>
 
 #include <Dictionaries/ClickHouseDictionarySource.h>
 #include <Dictionaries/DictionaryFactory.h>
@@ -31,7 +32,6 @@
 
 #include <re2_st/stringpiece.h>
 
-#include "Processors/Sources/BlocksListSource.h"
 #include "config.h"
 
 #if USE_VECTORSCAN
@@ -87,6 +87,32 @@ namespace
     }
 }
 
+struct ExternalRegexpQueryBuilder final : public ExternalQueryBuilder
+{
+    explicit ExternalRegexpQueryBuilder(const ExternalQueryBuilder & builder) : ExternalQueryBuilder(builder) {}
+
+    void composeLoadAllQuery(WriteBuffer & out) const override
+    {
+        writeString("SELECT id, parent_id, regexp, keys, values FROM ", out);
+        if (!db.empty())
+        {
+            writeQuoted(db, out);
+            writeChar('.', out);
+        }
+        if (!schema.empty())
+        {
+            writeQuoted(schema, out);
+            writeChar('.', out);
+        }
+        writeQuoted(table, out);
+        if (!where.empty())
+        {
+            writeString(" WHERE ", out);
+            writeString(where, out);
+        }
+    }
+};
+
 struct RegExpTreeDictionary::RegexTreeNode
 {
     std::vector<UInt64> children;
@@ -385,6 +411,8 @@ RegExpTreeDictionary::RegExpTreeDictionary(
         sample_block.insert(ColumnWithTypeAndName(std::make_shared<DataTypeArray>(std::make_shared<DataTypeString>()), kKeys));
         sample_block.insert(ColumnWithTypeAndName(std::make_shared<DataTypeArray>(std::make_shared<DataTypeString>()), kValues));
         ch_source->sample_block = std::move(sample_block);
+        ch_source->query_builder = std::make_shared<ExternalRegexpQueryBuilder>(*ch_source->query_builder);
+        ch_source->load_all_query = ch_source->query_builder->composeLoadAllQuery();
     }
 
     loadData();

tests/queries/0_stateless/02504_regexp_dictionary_table_source.sql

@@ -29,7 +29,7 @@ create dictionary regexp_dict1
     comment String default 'nothing'
 )
 PRIMARY KEY(regexp)
-SOURCE(CLICKHOUSE(QUERY concat('select * from ', currentDatabase() , '.regexp_dictionary_source_table')))
+SOURCE(CLICKHOUSE(TABLE 'regexp_dictionary_source_table'))
 LIFETIME(0)
 LAYOUT(regexp_tree);