MDEV-249 QUERY CACHE INFORMATION

2 files changed, 217 insertions, 0 deletions

diff --git a/plugin/qc_info/CMakeLists.txt b/plugin/qc_info/CMakeLists.txt
new file mode 100644
index 00000000000..f9c58f77466
--- /dev/null
+++ b/plugin/qc_info/CMakeLists.txt
@@ -0,0 +1,4 @@
+INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/sql ${CMAKE_SOURCE_DIR}/regex
+                    ${CMAKE_SOURCE_DIR}/extra/yassl/include)
+
+MYSQL_ADD_PLUGIN(QUERY_CACHE_INFO qc_info.cc)
diff --git a/plugin/qc_info/qc_info.cc b/plugin/qc_info/qc_info.cc
new file mode 100644
index 00000000000..e20b4dac5ea
--- /dev/null
+++ b/plugin/qc_info/qc_info.cc
@@ -0,0 +1,213 @@
+/*
+  Copyright (c) 2008, Roland Bouman
+  http://rpbouman.blogspot.com/
+  roland.bouman@gmail.com
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+      * Redistributions of source code must retain the above copyright
+        notice, this list of conditions and the following disclaimer.
+      * Redistributions in binary form must reproduce the above copyright
+        notice, this list of conditions and the following disclaimer in the
+        documentation and/or other materials provided with the distribution.
+      * Neither the name of the Roland Bouman nor the
+        names of the contributors may be used to endorse or promote products
+        derived from this software without specific prior written permission.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+
+/*
+ * TODO: report query cache flags
+ */
+#ifndef MYSQL_SERVER
+#define MYSQL_SERVER
+#endif
+
+#include <sql_cache.h>
+#include <sql_parse.h>          // check_global_access
+#include <sql_acl.h>            // PROCESS_ACL
+#include <sql_class.h>          // THD
+#include <table.h>              // ST_SCHEMA_TABLE
+#include <mysql/plugin.h>
+
+class Accessible_Query_Cache : public Query_cache {
+public:
+  HASH *get_queries()
+  {
+    return &this->queries;
+  }
+} *qc;
+
+bool schema_table_store_record(THD *thd, TABLE *table);
+
+#define MAX_STATEMENT_TEXT_LENGTH 32767
+#define COLUMN_STATEMENT_SCHEMA 0
+#define COLUMN_STATEMENT_TEXT 1
+#define COLUMN_RESULT_BLOCKS_COUNT 2
+#define COLUMN_RESULT_BLOCKS_SIZE 3
+#define COLUMN_RESULT_BLOCKS_SIZE_USED 4
+
+/* ST_FIELD_INFO is defined in table.h */
+static ST_FIELD_INFO qc_info_fields[]=
+{
+  {"STATEMENT_SCHEMA", NAME_LEN, MYSQL_TYPE_STRING, 0, 0, 0},
+  {"STATEMENT_TEXT", MAX_STATEMENT_TEXT_LENGTH, MYSQL_TYPE_STRING, 0, 0, 0},
+  {"RESULT_BLOCKS_COUNT", MY_INT32_NUM_DECIMAL_DIGITS, MYSQL_TYPE_LONG, 0, 0, 0},
+  {"RESULT_BLOCKS_SIZE", MY_INT32_NUM_DECIMAL_DIGITS, MYSQL_TYPE_LONGLONG, 0, 0, 0},
+  {"RESULT_BLOCKS_SIZE_USED", MY_INT32_NUM_DECIMAL_DIGITS, MYSQL_TYPE_LONGLONG, 0, 0, 0},
+  {0, 0, MYSQL_TYPE_STRING, 0, 0, 0}
+};
+
+static int qc_info_fill_table(THD *thd, TABLE_LIST *tables,
+                                              COND *cond)
+{
+  int status= 1;
+  CHARSET_INFO *scs= system_charset_info;
+  TABLE *table= tables->table;
+  HASH *queries = qc->get_queries();
+
+  /* one must have PROCESS privilege to see others' queries */
+  if (check_global_access(thd, PROCESS_ACL, true))
+    return 0;
+
+  if (qc->try_lock(thd))
+    return status;
+
+  /* loop through all queries in the query cache */
+  for (uint i= 0; i < queries->records; i++)
+  {
+    const uchar *query_cache_block_raw;
+    Query_cache_block* query_cache_block;
+    Query_cache_query* query_cache_query;
+    uint result_blocks_count;
+    ulonglong result_blocks_size;
+    ulonglong result_blocks_size_used;
+    Query_cache_block *first_result_block;
+    Query_cache_block *result_block;
+    const char *statement_text;
+    size_t statement_text_length;
+    const char *key, *db;
+    size_t key_length, db_length;
+
+    query_cache_block_raw = my_hash_element(queries, i);
+    query_cache_block = (Query_cache_block*)query_cache_block_raw;
+    if (query_cache_block->type != Query_cache_block::QUERY)
+      continue;
+
+    query_cache_query = query_cache_block->query();
+
+    /* Get the actual SQL statement for this query cache query */
+    statement_text = (const char*)query_cache_query->query();
+    statement_text_length = strlen(statement_text);
+    /* We truncate SQL statements up to MAX_STATEMENT_TEXT_LENGTH in our I_S table */
+    table->field[COLUMN_STATEMENT_TEXT]->store((char*)statement_text,
+           min(statement_text_length, MAX_STATEMENT_TEXT_LENGTH), scs);
+
+    /* get the entire key that identifies this query cache query */
+    key = (const char*)query_cache_query_get_key(query_cache_block_raw,
+                                                 &key_length, 0);
+    /* The database against which the statement is executed is part of the
+       query cache query key
+     */
+    compile_time_assert(QUERY_CACHE_DB_LENGTH_SIZE == 2); 
+    db= key + statement_text_length + 1 + QUERY_CACHE_DB_LENGTH_SIZE;
+    db_length= uint2korr(db - QUERY_CACHE_DB_LENGTH_SIZE);
+
+    table->field[COLUMN_STATEMENT_SCHEMA]->store(db, db_length, scs);
+
+    /* If we have result blocks, process them */
+    first_result_block= query_cache_query->result();
+    if(first_result_block)
+    {
+      /* initialize so we can loop over the result blocks*/
+      result_block= first_result_block;
+      result_blocks_count = 1;
+      result_blocks_size = result_block->length;
+      result_blocks_size_used = result_block->used;
+
+      /* loop over the result blocks*/
+      while((result_block= result_block->next)!=first_result_block)
+      {
+        /* calculate total number of result blocks */
+        result_blocks_count++;
+        /* calculate total size of result blocks */
+        result_blocks_size += result_block->length;
+        /* calculate total of used size of result blocks */
+        result_blocks_size_used += result_block->used;
+      }
+    }
+    else
+    {
+      result_blocks_count = 0;
+      result_blocks_size = 0;
+      result_blocks_size_used = 0;
+    }
+    table->field[COLUMN_RESULT_BLOCKS_COUNT]->store(result_blocks_count, 0);
+    table->field[COLUMN_RESULT_BLOCKS_SIZE]->store(result_blocks_size, 0);
+    table->field[COLUMN_RESULT_BLOCKS_SIZE_USED]->store(result_blocks_size_used, 0);
+
+    if (schema_table_store_record(thd, table))
+      goto cleanup;
+  }
+  status = 0;
+
+cleanup:
+  qc->unlock();
+  return status;
+}
+
+static int qc_info_plugin_init(void *p)
+{
+  ST_SCHEMA_TABLE *schema= (ST_SCHEMA_TABLE *)p;
+
+  schema->fields_info= qc_info_fields;
+  schema->fill_table= qc_info_fill_table;
+
+#ifdef _WIN32
+  qc = (Accessible_Query_Cache *)
+    GetProcAddress(GetModuleHandle(NULL), "?query_cache@@3VQuery_cache@@A");
+#else
+  qc = (Accessible_Query_Cache *)&query_cache;
+#endif
+
+  return qc == 0;
+}
+
+
+static struct st_mysql_information_schema qc_info_plugin=
+{ MYSQL_INFORMATION_SCHEMA_INTERFACE_VERSION };
+
+/*
+  Plugin library descriptor
+*/
+
+maria_declare_plugin(query_cache_info)
+{
+  MYSQL_INFORMATION_SCHEMA_PLUGIN,
+  &qc_info_plugin,
+  "QUERY_CACHE_INFO",
+  "Roland Bouman",
+  "Lists all queries in the query cache.",
+  PLUGIN_LICENSE_BSD,
+  qc_info_plugin_init, /* Plugin Init */
+  0,                          /* Plugin Deinit        */
+  0x0100,                     /* version, hex         */
+  NULL,                       /* status variables     */
+  NULL,                       /* system variables     */
+  "1.0",                      /* version as a string  */
+  MariaDB_PLUGIN_MATURITY_ALPHA
+}
+maria_declare_plugin_end;
+