| Bug #76060 | open and close of Instrinsic table causes negative MONITOR_TABLE_REFERENCE count | ||
|---|---|---|---|
| Submitted: | 26 Feb 2015 11:30 | Modified: | 4 Mar 2015 17:35 |
| Reporter: | Naga Satyanarayana Bodapati | Email Updates: | |
| Status: | Closed | Impact on me: | |
| Category: | MySQL Server: InnoDB storage engine | Severity: | S3 (Non-critical) |
| Version: | OS: | Any | |
| Assigned to: | CPU Architecture: | Any | |
[4 Mar 2015 17:35]
Daniel Price
Posted by developer: Fixed as of the upcoming 5.7.6, 5.8.0 releases, and here's the changelog entry: Opening and closing of intrinsic temporary tables resulted in a negative table reference count in "InnoDB" Monitor output. Thank you for the bug report.
Description: When instrinsic tables are opened & closed, they cause negative table ref count in monitor output How to repeat: I've verified from gdb. 1) intrinsic table open doesn't go via normal dictionary cache. So, no dict_open_on_id()/name() 2) So the table ref count is not incremented 3) But the table close operation goes via dict_table_close() which decrements MONITOR_TABLE_REFERENCE Suggested fix: Krunal suggested the fix on IM: infact we need to skip the dec action (04:36:44 PM) krunal.bauskar: --table->n_ref_count; /* Force persistent stats re-read upon next open of the table so that FLUSH TABLE can be used to forcibly fetch stats from disk if they have been manually modified. We reset table->stat_initialized only if table reference count is 0 because we do not want too frequent stats re-reads (e.g. in other cases than FLUSH TABLE). */ if (strchr(table->name.m_name, '/') != NULL && table->n_ref_count == 0 && dict_stats_is_persistent_enabled(table)) { dict_stats_deinit(table); } MONITOR_DEC(MONITOR_TABLE_REFERENCE); /* Intrinsic table is not added to dictionary table list so skip the next section that try to do that. */ if (dict_table_is_intrinsic(table)) { return; }