MySQL Bugs: #109012: it is better to delete the recv_addr_t::space

Bug #109012	it is better to delete the recv_addr_t::space_id to save some memory
Submitted:	5 Nov 2022 14:13	Modified:	7 Nov 2022 13:26
Reporter:	alex xing (OCA)	Email Updates:
Status:	Not a Bug	Impact on me:	None
Category:	MySQL Server: InnoDB storage engine	Severity:	S5 (Performance)
Version:	8.0.31	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
space_id saved in recv_addr_t is redundant, it is just the key of unordered_map(recv_sys_t::Spaces), and we can get space_id from the key.
So it is better to  delete the recv_addr_t::space_id to  save some memory

How to repeat:
just read the code

Suggested fix:
How to get the space_id in two apply scenarios
1) if page in buffer pool:(log0recv.cc:1266) 
change recv_apply_log_rec(pages.second); to recv_apply_log_rec(pages.second, space.first);
2) if apply from disk： (log0recv.cc:2823)
in recv_recover_page_func
change   recv_parse_or_apply_log_rec_body(recv->type, buf, buf_end,
                                                     recv_addr->space, 
                                                     recv_addr->page_no,
                                                     block, &mtr, 
                                                     ULINT_UNDEFINED, LSN_MAX)
to   
         recv_parse_or_apply_log_rec_body(recv->type, buf, buf_end,
                                                     block->page.id.space(), 
                                                     recv_addr->page_no,
                                                     block, &mtr, 
                                                     ULINT_UNDEFINED, LSN_MAX)

Hi Mr. xing,

Thank you for your bug report.

However, this field, as some others, are there for better performance and future enhancements.