Dear Hou, While playing with the 0003 patch (the patch may not be ready), I found that when the insert_exists event occurred, both apply_error_count and insert_exists_count was counted.
``` -- insert a tuple on the subscriber subscriber =# INSERT INTO tab VALUES (1); -- insert the same tuple on the publisher, which causes insert_exists conflict publisher =# INSERT INTO tab VALUES (1); -- after some time... subscriber =# SELECT * FROM pg_stat_subscription_stats; -[ RECORD 1 ]--------+------ subid | 16389 subname | sub apply_error_count | 16 sync_error_count | 0 insert_exists_count | 16 update_differ_count | 0 update_exists_count | 0 update_missing_count | 0 delete_differ_count | 0 delete_missing_count | 0 stats_reset | ``` Not tested, but I think this could also happen for the update_exists_count case, or sync_error_count may be counted when the tablesync worker detects the conflict. IIUC, the reason is that pgstat_report_subscription_error() is called in the PG_CATCH part in start_apply() even after ReportApplyConflict(ERROR) is called. What do you think of the current behavior? I wouldn't say I like that the same phenomenon is counted as several events. E.g., in the case of vacuum, the entry seemed to be separated based on the process by backends or autovacuum. I feel the spec is unfamiliar in that only insert_exists and update_exists are counted duplicated with the apply_error_count. An easy fix is to introduce a global variable which is turned on when the conflict is found. Thought? Best regards, Hayato Kuroda FUJITSU LIMITED
