Merge pull request #30436 from kitaisreal/executable-udf-clickhouse-example

ExecutableUDF example

src/Common/examples/CMakeLists.txt

@@ -77,3 +77,6 @@ target_link_libraries (average PRIVATE clickhouse_common_io)
 
 add_executable (shell_command_inout shell_command_inout.cpp)
 target_link_libraries (shell_command_inout PRIVATE clickhouse_common_io)
+
+add_executable (executable_udf executable_udf.cpp)
+target_link_libraries (executable_udf PRIVATE dbms)

src/Common/examples/executable_udf.cpp

@@ -0,0 +1,44 @@
+#include <vector>
+#include <string>
+#include <iomanip>
+
+#include <Common/SipHash.h>
+
+#include <IO/ReadBufferFromFileDescriptor.h>
+#include <IO/WriteBufferFromFileDescriptor.h>
+#include <IO/ReadHelpers.h>
+#include <IO/WriteHelpers.h>
+#include <Common/Stopwatch.h>
+
+using namespace DB;
+
+int main(int argc, char **argv)
+{
+    (void)(argc);
+    (void)(argv);
+
+    std::string buffer;
+
+    ReadBufferFromFileDescriptor read_buffer(0);
+    WriteBufferFromFileDescriptor write_buffer(1);
+    size_t rows = 0;
+    char dummy;
+
+    while (!read_buffer.eof()) {
+        readIntText(rows, read_buffer);
+        readChar(dummy, read_buffer);
+
+        for (size_t i = 0; i < rows; ++i) {
+            readString(buffer, read_buffer);
+            readChar(dummy, read_buffer);
+
+            writeString("Key ", write_buffer);
+            writeString(buffer, write_buffer);
+            writeChar('\n', write_buffer);
+        }
+
+        write_buffer.next();
+    }
+
+    return 0;
+}