| Bug #91864 | Group_member_info::conflict_detection_enable is always OFF in multi master mode | ||
|---|---|---|---|
| Submitted: | 2 Aug 2018 8:17 | Modified: | 6 Sep 2018 10:04 |
| Reporter: | Zhenghu Wen (OCA) | Email Updates: | |
| Status: | Closed | Impact on me: | |
| Category: | MySQL Server: Group Replication | Severity: | S3 (Non-critical) |
| Version: | 5.7.23 | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
[2 Aug 2018 10:55]
MySQL Verification Team
Hello Zhenghu, Thank you for the report. I have discussed this internally with GR Dev's and concluded that this is an expected behavior, please note that Certifier::enable_conflict_detection() function also sets local_member_info->enable_conflict_detection(); and this was fixed as part of BUG#25256910. Certifier::Certifier() :initialized(false), positive_cert(0), negative_cert(0), parallel_applier_last_committed_global(1), parallel_applier_sequence_number(2), certifying_already_applied_transactions(false), gtid_assignment_block_size(1), gtids_assigned_in_blocks_counter(1), conflict_detection_enable(!local_member_info->in_primary_mode()) certifier.cc ============ conflict_detection_enable(!local_member_info->in_primary_mode()) Also, confirmed that we do set conflict_detection temporarily ON during mode switch, this is for certifying intermediate transactions. regards, Umesh
[6 Aug 2018 1:36]
Zhenghu Wen
Hi, Umesh multi master mode: 1. in configure_group_member_manager(...), local_member_info::conflict_detection_enable is set to false; 2. in configure_and_start_applier_module(), Certifier::conflict_detection_enable is set to true,but local_member_info::conflict_detection_enable remain false; 3. Certifier::enable_conflict_detection() never called, so local_member_info::conflict_detection_enable always be false. is it an expected behavior? (indeed, local_member_info::conflict_detection_enable is useless in multi master mode) ----------------------------------------------------- I have discussed this internally with GR Dev's and concluded that this is an expected behavior, please note that Certifier::enable_conflict_detection() function also sets local_member_info->enable_conflict_detection(); and this was fixed as part of BUG#25256910. --------------- yes, Certifier::enable_conflict_detection() will set local_member_info->enable_conflict_detection(), but in multi master mode Certifier::enable_conflict_detection() had not been called. Certifier::Certifier() :initialized(false), positive_cert(0), negative_cert(0), parallel_applier_last_committed_global(1), parallel_applier_sequence_number(2), certifying_already_applied_transactions(false), gtid_assignment_block_size(1), gtids_assigned_in_blocks_counter(1), conflict_detection_enable(!local_member_info->in_primary_mode()) certifier.cc ============ conflict_detection_enable(!local_member_info->in_primary_mode()) ------------------------- conflict_detection_enable(!local_member_info->in_primary_mode()) will set Certifier::conflict_detection_enable, but not Group_member_info::conflict_detection_enable. so it remain false. regards, Zhenghu
[7 Aug 2018 8:53]
MySQL Verification Team
Thank you, Zhenghu. Verifying based on internal discussion with GR Dev. regards, Umesh
[6 Sep 2018 10:04]
David Moss
Posted by developer: Seems to be related to internal code changes, and customer appears to have been informed. Closing without change log entry.
Description: in Group_member_info constructor conflict_detection_enable is set to off even when single_primary_mode_var is off, and there are no place to update conflict_detection_enable to on; while when single_primary_mode_var is on, Group_member_info::conflict_detection_enable can be updated by Certifier::enable_conflict_detection() or Certifier::disable_conflict_detection() during distributed recovery procedure How to repeat: code review Suggested fix: Group_member_info::conflict_detection_enable should be re-init in Certifier::Certifier() for example, like that: if (conflict_detection_enable) local_member_info->enable_conflict_detection(); else local_member_info->disable_conflict_detection();