mysql_thd_attributes.h

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/* Copyright (c) 2021, 2026, Oracle and/or its affiliates.
 
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#ifndef MYSQL_THD_ATTRIBUTES_H
#define MYSQL_THD_ATTRIBUTES_H
 
#include <mysql/components/service.h>
#include <mysql/components/services/bits/thd.h>
 
/**
  @ingroup group_components_services_inventory
 
  THD Attributes service allows to obtain data associated with the THD
  object, which keeps various attributes of the user session.
 
  Currently, following attributes are supported:
 
  - Query Digest Text
  - Query Text
  - Host or IP
  - Schema
  - Command String ("command" of the return mysql_cstring_with_length type)
  - SQL Command String ("sql_command" of the return mysql_cstring_with_length
  type)
  - Is a Server substatement ("is_substatement" of the returned bool type).
  Stored functions and triggers are substatements; directly invoked stored
  procedures are not.
  - Query Character Set ("query_charset" of the return mysql_cstring_with_length
  type)
 
  @section thd_attributes_init Initialization
 
  The service can be instantiated using the registry service with the
  "mysql_thd_attributes" name.
 
  @code
  SERVICE_TYPE(registry) *registry = mysql_plugin_registry_acquire();
  my_service<SERVICE_TYPE(mysql_thd_attributes)>
                                         svc("mysql_thd_attributes", registry);
  if (svc.is_valid()) {
    // The service is ready to be used
  }
  @endcode
 
  @section thd_attributes_query_digest_text Query Digest Text
 
  Query Digest represents converted SQL statement to normalized form. The code
  below demonstrates how query digest can be obtained from the service.
 
  @code
  my_h_string str;
 
  mysql_thd_attributes->get(m_thd, "query_digest",
                                   reinterpret_cast<void *>(&str));
  @endcode
 
  The buffer can be fetched using the code below:
 
  @code
  char buf[1024]; // buffer must be big enough to store the digest
 
  mysql_string_converter->convert_to_buffer(str, buf, sizeof(buf), "utf8mb3");
  @endcode
 
  After the string content has been copied into another buffer, it must be
  destroyed:
 
  @code
  mysql_string_factory->destroy(str);
  @endcode
 
  @section thd_attributes_query_text Query Text
 
  Query text represents complete SQL text currently being executed within a
  given session. The example code is identical to the one for Query Digest, the
  only difference is that attribute name "sql_text" should be used in this
  case.
 
  @section thd_attributes_host_or_ip Host or IP
 
  Host or IP text contains host or IP (if host unavailable) belonging to a
  client associated with a given session. The example code is identical to the
  one for Query Digest, the only difference is that attribute name "host_or_ip"
  should be used in this case.
 
  @section thd_attributes_schema Schema
 
  Schema text contains a name of database currently in use by a
  client associated with a given session. The example code is identical to the
  one for Query Digest, the only difference is that attribute name "schema"
  should be used in this case.
*/
 
BEGIN_SERVICE_DEFINITION(mysql_thd_attributes)
 
/**
  Get THD attribute.
 
  Currently, following attributes are supported:
 
  - Query Digest Text ("query_digest" of the returned my_h_string type)
  - Query Text ("sql_text" of the returned my_h_string type)
  - Host or IP ("host_or_ip" of the returned my_h_string type)
  - Schema ("schema" of the returned my_h_string type)
  - Is Upgrade Thread ("is_upgrade_thread" of the returned bool type)
  - Is Init File System Thread ("is_init_file_thread" of the returned bool type)
  - Command String ("command" of the return mysql_cstring_with_length type)
  - SQL Command String ("sql_command" of the return mysql_cstring_with_length
  type)
  - Is a Server substatement ("is_substatement" of the returned bool type).
  Stored functions and triggers are substatements; directly invoked stored
  procedures are not.
  - Query Character Set ("query_charset" of the return mysql_cstring_with_length
  type)
  - status variable ("thd_status" of the returned uint16 type). if session is
    OK, session is killed, query is killed or timeout
  - time-zone name variable ("time_zone_name" of the returned
    mysql_cstring_with_length type)
  - Query execution status ("da_status" of the returned uint16 type).
 
  @param      thd           Session THD object.
  @param      name          Name of the attribute to be set.
  @param[out] inout_pvalue  Iterator pointer.
 
  @return
    @retval FALSE Succeeded.
    @retval TRUE  Failed.
*/
DECLARE_BOOL_METHOD(get, (MYSQL_THD thd, const char *name, void *inout_pvalue));
 
/**
  Set THD attribute.
 
  Currently the implementation does not support setting of any attribute.
 
  @param      thd           Session THD object.
  @param      name          Name of the attribute to be set.
  @param[out] inout_pvalue  Iterator pointer.
 
  @return The function always fail and return TRUE value.
*/
DECLARE_BOOL_METHOD(set, (MYSQL_THD thd, const char *name, void *inout_pvalue));
 
END_SERVICE_DEFINITION(mysql_thd_attributes)
 
#endif /* MYSQL_THD_ATTRIBUTES_H */