MDEV-26782 InnoDB temporary tablespace: reclaiming of free space does not work
The motivation of this change is to allow undo pages for temporary tables
to be marked free as often as possible, so that we can avoid buf_pool.LRU
eviction of undo pages that contain data that is no longer needed.
For temporary tables, no MVCC or purge of history is needed, and
reusing cached undo log pages might not help that much.
It is possible that this may cause some performance regression due to
more frequent allocation and freeing of undo log pages.
trx_write_serialisation_history(): Never cache temporary undo log pages.
trx_undo_reuse_cached(): Assert that the rollback segment is persistent.
trx_undo_assign_low(): Add template<bool is_temp>. Never invoke
trx_undo_reuse_cached() for temporary tables.
Let us remove explicit updates of MONITOR_NUM_UNDO_SLOT_USED
and MONITOR_NUM_UNDO_SLOT_CACHED, and let us compute the rough values
from trx_sys.rseg_array[] on demand.
MDEV-29593 Purge misses a chance to free not-yet-reused undo pages
trx_purge_truncate_rseg_history(): If all other conditions for
invoking trx_purge_remove_log_hdr() hold, but the state is
TRX_UNDO_CACHED instead of TRX_UNDO_TO_PURGE, detach and free it.
MDEV-26071: rpl.rpl_perfschema_applier_status_by_worker failed in bb …
…with: Test assertion failed
Problem:
=======
Assertion text: 'Value returned by SSS and PS table for Last_Error_Number
should be same.'
Assertion condition: '"1146" = "0"'
Assertion condition, interpolated: '"1146" = "0"'
Assertion result: '0'
Analysis:
========
In parallel replication when slave is started the worker pool gets
activated and it gets cleared when slave stops. Each time the worker pool
gets activated a backup worker pool also gets created to store worker
specific perforance schema information in case of errors. On error, all
relevant information is copied from rpl_parallel_thread to rli and it gets
cleared from thread. Then server waits for all workers to complete their
work, during this stage performance schema table specific worker info is
stored into the backup pool and finally the actual pool gets cleared. If
users query the performance schema table to know the status of workers the
information from backup pool will be used. The test simulates
ER_NO_SUCH_TABLE error and verifies the worker information in pfs table.
Test works fine if execution occurs in following order.
Step 1. Error occurred 'worker information is copied to backup pool'.
Step 2. handle_slave_sql invokes 'rpl_parallel_resize_pool_if_no_slaves' to
deactivate worker pool, it marks the pool->count=0
Step 3. PFS table is queried, since actual pool is deactivated backup pool
information is read.
If the Step 3 happens prior to Step2 the pool is yet to be deactivated and
the actual pool is read, which doesn't have any error details as they were
cleared. Hence test ocasionally fails.
Fix:
===
Upon error mark the back pool as being active so that if PFS table is
quried since the backup pool is flagged as valid its information will be
read, in case it is not flagged regular pool will be read.
This work is one of the last pieces created by the late Sujatha Sivakumar.
MDEV-29545 InnoDB: Can't find record during replace stmt
Problem:
========
- InnoDB replace statement returns can't find record as result during
bulk insert operation. InnoDB returns DB_END_OF_INDEX blindly when
bulk transaction is visible to current transaction even though
the search tuple is inserted as a part of current replace statement.
Solution:
=========
row_search_mvcc(): InnoDB should allow the transaction to read
all the rows when innodb intends to do any locking on the
record even though bulk insert transaction changes are
visible to the current transaction
MDEV-30900 Crash on macOS due to zero-initialized buf_dblwr.write_cond
buf_dblwr_t::init(), buf_dblwr_t::close(): Cover also write_cond,
which was added in commit a55b951e6082a4ce9a1f2ed5ee176ea7dbbaf1f2
without explicit initialization. On GNU/Linux, PTHREAD_COND_INITIALIZER
is a zero-initializer. That is why the default zero initialization
happened to work on that platform.
