MDEV-12458: Variable and log records to indicate RocksDB version are missing

Added a system variabe rocsdb_git_hash to MyRocks which tell us the version of RocksDB being used

cmake/make_dist.cmake.in

@@ -52,6 +52,9 @@ IF(GIT_EXECUTABLE)
   ENDIF()
 ENDIF()
 
+CONFIGURE_FILE(${CMAKE_BINARY_DIR}/storage/rocksdb/rdb_source_revision.h
+       ${PACKAGE_DIR}/storage/rocksdb/rdb_source_revision.h COPYONLY)
+
 IF(NOT GIT_EXECUTABLE)
   MESSAGE(STATUS "git not found or source dir is not a repo, use CPack")
   

storage/rocksdb/CMakeLists.txt

@@ -220,3 +220,18 @@ IF(MSVC)
   # Some checks in C++ runtime that make debug build much slower
   ADD_DEFINITIONS(-D_ITERATOR_DEBUG_LEVEL=0)
 ENDIF()
+
+IF(GIT_EXECUTABLE)
+  EXECUTE_PROCESS(
+    COMMAND ${GIT_EXECUTABLE} rev-parse HEAD
+      WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/rocksdb
+       OUTPUT_VARIABLE OUT RESULT_VARIABLE RES)
+  IF(RES EQUAL 0)
+    STRING(REGEX REPLACE "\n$" "" ROCKSDB_GIT_HASH "${OUT}")
+  ENDIF()
+ENDIF()
+IF(ROCKSDB_GIT_HASH OR
+  (NOT EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/rdb_source_revision.h))
+  CONFIGURE_FILE(${CMAKE_CURRENT_SOURCE_DIR}/rdb_source_revision.h.in
+               ${CMAKE_CURRENT_BINARY_DIR}/rdb_source_revision.h )
+ENDIF()

storage/rocksdb/ha_rocksdb.cc

@@ -70,6 +70,7 @@
 #include "rocksdb/utilities/memory_util.h"
 #include "rocksdb/utilities/sim_cache.h"
 #include "util/stop_watch.h"
+#include "./rdb_source_revision.h"
 
 /* MyRocks includes */
 #include "./event_listener.h"
@@ -494,6 +495,7 @@ static uint32_t rocksdb_table_stats_sampling_pct;
 static my_bool rocksdb_enable_bulk_load_api = 1;
 static my_bool rocksdb_print_snapshot_conflict_queries = 0;
 static my_bool rocksdb_large_prefix = 0;
+static char* rocksdb_git_hash;
 
 char *compression_types_val=
   const_cast<char*>(get_rocksdb_supported_compression_types());
@@ -650,6 +652,11 @@ static MYSQL_SYSVAR_BOOL(enable_bulk_load_api, rocksdb_enable_bulk_load_api,
                          "Enables using SstFileWriter for bulk loading",
                          nullptr, nullptr, rocksdb_enable_bulk_load_api);
 
+static MYSQL_SYSVAR_STR(git_hash, rocksdb_git_hash,
+                        PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
+                        "Git revision of the RocksDB library used by MyRocks",
+                        nullptr, nullptr, ROCKSDB_GIT_HASH);
+
 static MYSQL_THDVAR_STR(tmpdir, PLUGIN_VAR_OPCMDARG | PLUGIN_VAR_MEMALLOC,
                         "Directory for temporary files during DDL operations.",
                         nullptr, nullptr, "");
@@ -1633,6 +1640,7 @@ static struct st_mysql_sys_var *rocksdb_system_variables[] = {
     MYSQL_SYSVAR(table_stats_sampling_pct),
 
     MYSQL_SYSVAR(large_prefix),
+    MYSQL_SYSVAR(git_hash),
     nullptr};
 
 static rocksdb::WriteOptions

storage/rocksdb/mysql-test/rocksdb/r/rocksdb.result

@@ -924,6 +924,7 @@ rocksdb_force_compute_memtable_stats_cachetime	0
 rocksdb_force_flush_memtable_and_lzero_now	OFF
 rocksdb_force_flush_memtable_now	OFF
 rocksdb_force_index_records_in_range	0
+rocksdb_git_hash	#
 rocksdb_hash_index_allow_collision	ON
 rocksdb_index_type	kBinarySearch
 rocksdb_info_log_level	error_level

storage/rocksdb/mysql-test/rocksdb/t/rocksdb.test

@@ -786,6 +786,8 @@ drop table t45;
 --echo # Now it fails if there is data overlap with what
 --echo # already exists
 --echo #
+
+--replace_regex /[a-f0-9]{40}/#/
 show variables 
 where 
   variable_name like 'rocksdb%' and 

storage/rocksdb/mysql-test/rocksdb_sys_vars/t/rocksdb_git_hash_basic.test

+--source include/have_rocksdb.inc
+
+--let $sys_var=ROCKSDB_GIT_HASH
+--let $read_only=1
+--let $session=0
+--source include/rocksdb_sys_var.inc

storage/rocksdb/rdb_source_revision.h.in

+#define ROCKSDB_GIT_HASH "@ROCKSDB_GIT_HASH@"