MDEV-23855: Remove fil_system.LRU and reduce fil_system.mutex contention

Also fixes MDEV-23929: innodb_flush_neighbors is not being ignored
for system tablespace on SSD

When the maximum configured number of file is exceeded, InnoDB will
close data files. We used to maintain a fil_system.LRU list and
a counter fil_node_t::n_pending to achieve this, at the huge cost
of multiple fil_system.mutex operations per I/O operation.

fil_node_open_file_low(): Implement a FIFO replacement policy:
The last opened file will be moved to the end of fil_system.space_list,
and files will be closed from the start of the list. However, we will
not move tablespaces in fil_system.space_list while
i_s_tablespaces_encryption_fill_table() is executing
(producing output for INFORMATION_SCHEMA.INNODB_TABLESPACES_ENCRYPTION)
because it may cause information of some tablespaces to go missing.
We also avoid this in mariabackup --backup because datafiles_iter_next()
assumes that the ordering is not changed.

IORequest: Fold more parameters to IORequest::type.

fil_space_t::io(): Replaces fil_io().

fil_space_t::flush(): Replaces fil_flush().

OS_AIO_IBUF: Remove. We will always issue synchronous reads of the
change buffer pages in buf_read_page_low().

We will always ignore some errors for background reads.

This should reduce fil_system.mutex contention a little.

fil_node_t::complete_write(): Replaces fil_node_t::complete_io().
On both read and write completion, fil_space_t::release_for_io()
will have to be called.

fil_space_t::io(): Do not acquire fil_system.mutex in the normal
code path.

xb_delta_open_matching_space(): Do not try to open the system tablespace
which was already opened. This fixes a file sharing violation in
mariabackup --prepare --incremental.

Reviewed by: Vladislav Vaintroub

1 files changed, 1 insertions, 1 deletions

diff --git a/storage/innobase/dict/dict0crea.cc b/storage/innobase/dict/dict0crea.cc
index 7a27160ccd5..fb3247ecdcf 100644
--- a/storage/innobase/dict/dict0crea.cc
+++ b/storage/innobase/dict/dict0crea.cc
@@ -951,7 +951,7 @@ void dict_drop_index_tree(btr_pcur_t* pcur, trx_t* trx, mtr_t* mtr)
 	if (fil_space_t* s = fil_space_acquire_silent(space_id)) {
 		/* Ensure that the tablespace file exists
 		in order to avoid a crash in buf_page_get_gen(). */
-		if (s->size || fil_space_get_size(space_id)) {
+		if (root_page_no < s->get_size()) {
 			btr_free_if_exists(page_id_t(space_id, root_page_no),
 					   s->zip_size(),
 					   mach_read_from_8(ptr), mtr);