Bug #90518
Updated by Sybille Peters about 4 years ago
*Update*: My initial idea did not work out. I will investigate further ... ---- Recently we are experiencing increasing number of exceptions and "too many connections" on TYPO3 9.5.13 in combination with DELETE queries on cf_cache_rootline and cf_cache_rootline_tags that take excessively long. Obviously, this is causing massive problems. Findings: * Increasing number of exceptions: An exception occurred while executing 'INSERT INTO `cf_cache_rootline ... Lock wait timeout exceeded; try restarting transaction | Doctrine\DBAL\Exception This seems to be correlated with excessively long DELETE queries on cf_cache_rootline and cf_cache_rootline_tags with 2 JOINs. <pre><code class="text"> # Time: 200221 11:44:21 # User@Host: ------ @ [------] # Thread_id: 13694456 Schema: ----- QC_hit: No # Query_time: *2212.109482* Lock_time: 0.000340 Rows_sent: 0 Rows_examined: *1007307838* # Rows_affected: *94732* SET timestamp=1582281861; DELETE tags2, cache1 FROM cf_cache_rootline_tags AS tags1 JOIN cf_cache_rootline_tags AS tags2 ON tags1.identifier = tags2.identifier JOIN cf_cache_rootline AS cache1 ON tags1.identifier = cache1.identifier WHERE tags1.tag IN ('pageId_3'); </code></pre> (I blanked out some IP addresses etc.) in Typo3DatabaseBackend::flushByTags()