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This patch handles problems which occured with a large number of pages and also for a large number of records to be checked for broken links. The problems previously resulted in "Prepared statement contains too many placeholders" exceptions and consumption of too much RAM and (possibly) out of memory errors. Technical details about the implementation follows because this is handled slightly differently than in other areas of the core. LinkValidator used named placeholders to build database queries, and the EditableRestriction class also used a number of placeholder. Technically 'doctrine/dbal' explodes named placeholders for array values with quote type 'PARAM_INT_ARRAY' or 'PARAM_STR_ARRAY' to single unnamed placeholders for each value, using one placeholder for each array value. If multiple array value placeholder are used with a large number of values this could quickly emit the "Prepared statement contains too many placeholders" error as the limit is reached. The limit differs beetween the various database systems. One way to work around this issue is to do database operations in chunks, but it could become quite difficult to calculate the chunk size beforehand. Array values are mainly used for 'in()' or 'notIn()' query expressions, which naturally do not not have direct limits for the value count in it through all supported dbms systems. This opens the possibility to use direct value lists for these expressions. There are other dbms limitations depending on the used dbms (for example on mariadb/mysql 'max_allowed_packets', max query size setting for SQLite), which may be adjusted in some cases. However we could not safely expect that these values are monitored and adjusted, so we still need to do database operations in chunks, but make it a little easier for 'chunksize' calculations. During testing on an instance with a large number of pages, it was found that LinkValidator used up a lot of memory, reaching the configured memory limit of 2G on that system, which itself was very high already (and far beyond the recommended 256MB limit). Instead of collecting unlimited results in an array before checking links against this array, doing this for each record directly avoids excessive memory consumption during link checking. It was decided to do this in this patch directly instead of a separate patch, as this patch otherwise would not be testable in real instances. This patch does the following: * introduce two method to implode value arrays in QueryHelper * replace placeholder in EditableRestriction with quoted values * replace placeholder in BrokenLinksRepository with quoted values * introduce chunk database operations in BrokenLinkRepository * introduce chunk database operations in LinkAnalyzer * move $results array and call checkLinks() on it to the inner loop to process this for each record (instead of accumulating the results in a huge array. In the future we need to investigate and find a more generic way to handle such scenarios for larger instances. This may take some time and investigation to do this properly and in a reusable way. To not stall the bugfix further, we are doing the workarounds in this patch to solve these issues in the meantime. Resolves: #92493 Releases: master, 11.5 Change-Id: I9a596df6749d07afee9c5ac37266b876ddc6e297 Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/66896 Tested-by:
core-ci <typo3@b13.com> Tested-by:
Stefan Bürk <stefan@buerk.tech> Tested-by:
Christian Kuhn <lolli@schwarzbu.ch> Reviewed-by:
7fecd98c
