Hello Serg!
TLDR the commit is verbalized, junks are removed, `using` is preferred
except for tiny getters.
On Fri, 12 Nov 2021 at 19:20, Sergei Golubchik <s...@mariadb.org> wrote:
> Hi, Nikita!
>
> On Nov 12, Nikita Malyavin wrote:
> > revision-id: 4af7a583802 (mariadb-10.5.2-474-g4af7a583802)
> > parent(s): 2da3dc5d422
> > author: Nikita Malyavin
> > committer: Nikita Malyavin
> > timestamp: 2021-01-08 20:59:09 +1000
> > message:
> >
> > Refactor MYSQL_BIN_LOG: extract Event_log ancestor
>
> Would be good to have some explanation here. I understand that you'll
> use this refactoring in following commits, but conceptually, what
> Event_log is?
>
> I mean, like
>
> Event_log is a log where Log_event_xxx events are written, but not
> _something else that MYSQL_BIN_LOG is and Event_log isn't_
>
> or
>
> Event_log is a log where Log_event_xxx events are written. While
> MYSQL_BIN_LOG is Event_log that also does ....
>
Right. Adding as follows:
Event_log is supposed to be a basic logging class that can write events in
a single file.
MYSQL_BIN_LOG in comparison will have:
* rotation support
* index files
* purging
* gtid, xid and other transactional information handling.
* is dedicated for a general-purpose binlog
>
> > diff --git a/sql/log.cc b/sql/log.cc
> > index 827a34c2883..6f4e3191588 100644
> > --- a/sql/log.cc
> > +++ b/sql/log.cc
> > @@ -3701,64 +3765,25 @@ bool MYSQL_BIN_LOG::open(const char *log_name,
> > write_file_name_to_index_file= 1;
> > }
>
> a bit strange that MYSQL_BIN_LOG::open doesn't use Event_log::open
>
Yes, I think MYSQL_BIN_LOG is left too specialized for some particular
needs. I did not want to touch all that tech debt and left as is.
Besides, there's nothing weird in not calling the superclass's method.
I mean, in future commits [spoiler alert!] it will be used anyway:)
>
> > diff --git a/sql/log.h b/sql/log.h
> > index 73cd66d5a4a..74c409e1ac7 100644
> > --- a/sql/log.h
> > +++ b/sql/log.h
> > @@ -327,6 +327,7 @@ class MYSQL_LOG
> > bool strip_ext, char *buff);
> > virtual int generate_new_name(char *new_name, const char *log_name,
> > ulong next_log_number);
> > + inline mysql_mutex_t* get_log_lock() { return &LOCK_log; }
> > protected:
> > /* LOCK_log is inited by init_pthread_objects() */
> > mysql_mutex_t LOCK_log;
> > @@ -376,6 +377,64 @@ struct Rows_event_factory
> > }
> > };
> >
> > +class Event_log: public MYSQL_LOG
> > +{
> > +public:
> > +#if !defined(MYSQL_CLIENT)
> > + Rows_log_event*
> > + prepare_pending_rows_event(THD *thd, TABLE* table,
> > + binlog_cache_data *cache_data,
> > + uint32 serv_id, size_t needed,
> > + bool is_transactional,
> > + Rows_event_factory event_factory);
>
> forgot to delete the same from MYSQL_BIN_LOG
>
> > +#endif
> > +
> > + bool flush_and_sync(bool *synced);
>
> same
wow, i wonder how did you notice.
>
> > + void cleanup()
> > + {
> > + if (inited)
> > + mysql_mutex_destroy(&LOCK_binlog_end_pos);
> > +
> > + MYSQL_LOG::cleanup();
> > + }
> > + void init_pthread_objects()
> > + {
> > + MYSQL_LOG::init_pthread_objects();
> > +
> > + mysql_mutex_init(m_key_LOCK_binlog_end_pos, &LOCK_binlog_end_pos,
> > + MY_MUTEX_INIT_SLOW);
> > + }
> > +
> > + bool open(
> > + const char *log_name,
> > + enum_log_type log_type,
> > + const char *new_name, ulong next_file_number,
> > + enum cache_type io_cache_type_arg);
> > + IO_CACHE *get_log_file() { return &log_file; }
> > +
> > + int write_description_event(enum_binlog_checksum_alg checksum_alg,
> > + bool encrypt, bool dont_set_created);
> > +
> > + bool write_event(Log_event *ev, binlog_cache_data *data, IO_CACHE
> *file);
> > +};
> > +
> > /* Tell the io thread if we can delay the master info sync. */
> > #define SEMI_SYNC_SLAVE_DELAY_SYNC 1
> > /* Tell the io thread if the current event needs a ack. */
> > @@ -451,7 +510,7 @@ class binlog_cache_data;
> > struct rpl_gtid;
> > struct wait_for_commit;
> >
> > -class MYSQL_BIN_LOG: public TC_LOG, private MYSQL_LOG
> > +class MYSQL_BIN_LOG: public TC_LOG, private Event_log
> > {
> > /** The instrumentation key to use for @ LOCK_index. */
> > PSI_mutex_key m_key_LOCK_index;
> > @@ -849,15 +901,13 @@ class MYSQL_BIN_LOG: public TC_LOG, private
> MYSQL_LOG
> >
> > - bool write_event(Log_event *ev, binlog_cache_data *data, IO_CACHE
> *file);
> > + bool write_event(Log_event *ev, binlog_cache_data *data, IO_CACHE
> *file)
> > + { return Event_log::write_event(ev, data, file); }
>
> Perhaps
>
> using Event_log::write_event(Log_event *ev, binlog_cache_data *data,
> IO_CACHE *file);
>
> ?
>
Indeed:)
>
> > bool write_event(Log_event *ev) { return write_event(ev, 0,
> &log_file); }
> >
> > bool write_event_buffer(uchar* buf,uint len);
> > @@ -918,7 +968,6 @@ class MYSQL_BIN_LOG: public TC_LOG, private MYSQL_LOG
> > uint next_file_id();
> > inline char* get_index_fname() { return index_file_name;}
> > inline char* get_log_fname() { return log_file_name; }
> > - inline char* get_name() { return name; }
> > inline mysql_mutex_t* get_log_lock() { return &LOCK_log; }
>
> should remove that too, I reckon
>
Well, these are so tiny getters so I'm not sure, whether is it more
comfortable to jump back and forth to check what's there in Event_log, or
just admit the cost of duplication for a better read comfort. I'd leave it
as it is now.
>
> > inline mysql_cond_t* get_bin_log_cond() { return
> &COND_bin_log_updated; }
> > inline IO_CACHE* get_log_file() { return &log_file; }
--
Yours truly,
Nikita Malyavin
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