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6e83457b1b
" This series introduces PER PARTITION LIMIT to CQL. Protocol and storage is already capable of applying per-partition limits, so for nonpaged queries the changes are superficial - a variable is parsed and passed down. For paged queries and filtering the situation is a little bit more complicated due to corner cases: results for one partition can be split over 2 or more pages, filtering may drop rows, etc. To solve these, another variable is added to paging state - the number of rows already returned from last served partition. Note that "last" partition may be stretched over any number of pages, not just the last one, which is a case especially when considering filtering. As a result, per-partition-limiting queries are not eligible for page generator optimization, because they may need to have their results locally filtered for extraneous rows (e.g. when the next page asks for per-partition limit 5, but we already received 4 rows from the last partition, so need just 1 more from last partition key, but 5 from all next ones). Tests: unit (dev) Fixes #2202 " * 'add_per_partition_limit_3' of https://github.com/psarna/scylla: tests: remove superficial ignore_order from filtering tests tests: add filtering with per partition key limit test tests: publish extract_paging_state and count_rows_fetched tests: fix order of parameters in with_rows_ignore_order cql3,grammar: add PER PARTITION LIMIT idl,service: add persistent last partition row count cql3: prevent page generator usage for per-partition limit cql3: add checking for previous partition count to filtering pager: add adjusting per-partition row limit cql3: obey per partition limit for filtering cql3: clean up unneeded limit variables cql3: obey per partition limit for select statement cql3: add get_per_partition_limit cql3: add per_partition_limit to CQL statement