/***************************************************************************** Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved. Copyright (c) 2017, MariaDB Corporation. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA *****************************************************************************/ /**************************************************//** @file buf/buf0lru.cc The database buffer replacement algorithm Created 11/5/1995 Heikki Tuuri *******************************************************/ #include "buf0lru.h" #include "ut0byte.h" #include "ut0rnd.h" #include "sync0rw.h" #include "hash0hash.h" #include "os0event.h" #include "fil0fil.h" #include "btr0btr.h" #include "buf0buddy.h" #include "buf0buf.h" #include "buf0dblwr.h" #include "buf0flu.h" #include "buf0rea.h" #include "btr0sea.h" #include "ibuf0ibuf.h" #include "os0file.h" #include "page0zip.h" #include "log0recv.h" #include "srv0srv.h" #include "srv0mon.h" #include "lock0lock.h" /** The number of blocks from the LRU_old pointer onward, including the block pointed to, must be buf_pool->LRU_old_ratio/BUF_LRU_OLD_RATIO_DIV of the whole LRU list length, except that the tolerance defined below is allowed. Note that the tolerance must be small enough such that for even the BUF_LRU_OLD_MIN_LEN long LRU list, the LRU_old pointer is not allowed to point to either end of the LRU list. */ static const ulint BUF_LRU_OLD_TOLERANCE = 20; /** The minimum amount of non-old blocks when the LRU_old list exists (that is, when there are more than BUF_LRU_OLD_MIN_LEN blocks). @see buf_LRU_old_adjust_len */ #define BUF_LRU_NON_OLD_MIN_LEN 5 #if BUF_LRU_NON_OLD_MIN_LEN >= BUF_LRU_OLD_MIN_LEN # error "BUF_LRU_NON_OLD_MIN_LEN >= BUF_LRU_OLD_MIN_LEN" #endif /** When dropping the search hash index entries before deleting an ibd file, we build a local array of pages belonging to that tablespace in the buffer pool. Following is the size of that array. We also release buf_pool->mutex after scanning this many pages of the flush_list when dropping a table. This is to ensure that other threads are not blocked for extended period of time when using very large buffer pools. */ static const ulint BUF_LRU_DROP_SEARCH_SIZE = 1024; /** We scan these many blocks when looking for a clean page to evict during LRU eviction. */ static const ulint BUF_LRU_SEARCH_SCAN_THRESHOLD = 100; /** If we switch on the InnoDB monitor because there are too few available frames in the buffer pool, we set this to TRUE */ static bool buf_lru_switched_on_innodb_mon = false; /******************************************************************//** These statistics are not 'of' LRU but 'for' LRU. We keep count of I/O and page_zip_decompress() operations. Based on the statistics, buf_LRU_evict_from_unzip_LRU() decides if we want to evict from unzip_LRU or the regular LRU. From unzip_LRU, we will only evict the uncompressed frame (meaning we can evict dirty blocks as well). From the regular LRU, we will evict the entire block (i.e.: both the uncompressed and compressed data), which must be clean. */ /* @{ */ /** Number of intervals for which we keep the history of these stats. Each interval is 1 second, defined by the rate at which srv_error_monitor_thread() calls buf_LRU_stat_update(). */ static const ulint BUF_LRU_STAT_N_INTERVAL = 50; /** Co-efficient with which we multiply I/O operations to equate them with page_zip_decompress() operations. */ static const ulint BUF_LRU_IO_TO_UNZIP_FACTOR = 50; /** Sampled values buf_LRU_stat_cur. Not protected by any mutex. Updated by buf_LRU_stat_update(). */ static buf_LRU_stat_t buf_LRU_stat_arr[BUF_LRU_STAT_N_INTERVAL]; /** Cursor to buf_LRU_stat_arr[] that is updated in a round-robin fashion. */ static ulint buf_LRU_stat_arr_ind; /** Current operation counters. Not protected by any mutex. Cleared by buf_LRU_stat_update(). */ buf_LRU_stat_t buf_LRU_stat_cur; /** Running sum of past values of buf_LRU_stat_cur. Updated by buf_LRU_stat_update(). Not Protected by any mutex. */ buf_LRU_stat_t buf_LRU_stat_sum; /* @} */ /** @name Heuristics for detecting index scan @{ */ /** Move blocks to "new" LRU list only if the first access was at least this many milliseconds ago. Not protected by any mutex or latch. */ uint buf_LRU_old_threshold_ms; /* @} */ /******************************************************************//** Takes a block out of the LRU list and page hash table. If the block is compressed-only (BUF_BLOCK_ZIP_PAGE), the object will be freed. The caller must hold buf_pool->mutex, the buf_page_get_mutex() mutex and the appropriate hash_lock. This function will release the buf_page_get_mutex() and the hash_lock. If a compressed page is freed other compressed pages may be relocated. @retval true if BUF_BLOCK_FILE_PAGE was removed from page_hash. The caller needs to free the page to the free list @retval false if BUF_BLOCK_ZIP_PAGE was removed from page_hash. In this case the block is already returned to the buddy allocator. */ static MY_ATTRIBUTE((warn_unused_result)) bool buf_LRU_block_remove_hashed( /*========================*/ buf_page_t* bpage, /*!< in: block, must contain a file page and be in a state where it can be freed; there may or may not be a hash index to the page */ bool zip); /*!< in: true if should remove also the compressed page of an uncompressed page */ /******************************************************************//** Puts a file page whose has no hash index to the free list. */ static void buf_LRU_block_free_hashed_page( /*===========================*/ buf_block_t* block); /*!< in: block, must contain a file page and be in a state where it can be freed */ /******************************************************************//** Increases LRU size in bytes with page size inline function */ static inline void incr_LRU_size_in_bytes( /*===================*/ buf_page_t* bpage, /*!< in: control block */ buf_pool_t* buf_pool) /*!< in: buffer pool instance */ { ut_ad(buf_pool_mutex_own(buf_pool)); buf_pool->stat.LRU_bytes += bpage->size.physical(); ut_ad(buf_pool->stat.LRU_bytes <= buf_pool->curr_pool_size); } /******************************************************************//** Determines if the unzip_LRU list should be used for evicting a victim instead of the general LRU list. @return TRUE if should use unzip_LRU */ ibool buf_LRU_evict_from_unzip_LRU( /*=========================*/ buf_pool_t* buf_pool) { ut_ad(buf_pool_mutex_own(buf_pool)); /* If the unzip_LRU list is empty, we can only use the LRU. */ if (UT_LIST_GET_LEN(buf_pool->unzip_LRU) == 0) { return(FALSE); } /* If unzip_LRU is at most 10% of the size of the LRU list, then use the LRU. This slack allows us to keep hot decompressed pages in the buffer pool. */ if (UT_LIST_GET_LEN(buf_pool->unzip_LRU) <= UT_LIST_GET_LEN(buf_pool->LRU) / 10) { return(FALSE); } /* If eviction hasn't started yet, we assume by default that a workload is disk bound. */ if (buf_pool->freed_page_clock == 0) { return(TRUE); } /* Calculate the average over past intervals, and add the values of the current interval. */ ulint io_avg = buf_LRU_stat_sum.io / BUF_LRU_STAT_N_INTERVAL + buf_LRU_stat_cur.io; ulint unzip_avg = buf_LRU_stat_sum.unzip / BUF_LRU_STAT_N_INTERVAL + buf_LRU_stat_cur.unzip; /* Decide based on our formula. If the load is I/O bound (unzip_avg is smaller than the weighted io_avg), evict an uncompressed frame from unzip_LRU. Otherwise we assume that the load is CPU bound and evict from the regular LRU. */ return(unzip_avg <= io_avg * BUF_LRU_IO_TO_UNZIP_FACTOR); } #ifdef BTR_CUR_HASH_ADAPT /** Attempts to drop page hash index on a batch of pages belonging to a particular space id. @param[in] space_id space id @param[in] page_size page size @param[in] arr array of page_no @param[in] count number of entries in array */ static void buf_LRU_drop_page_hash_batch( ulint space_id, const page_size_t& page_size, const ulint* arr, ulint count) { ut_ad(count <= BUF_LRU_DROP_SEARCH_SIZE); for (ulint i = 0; i < count; ++i, ++arr) { /* While our only caller buf_LRU_drop_page_hash_for_tablespace() is being executed for DROP TABLE or similar, the table cannot be evicted from the buffer pool. Note: this should not be executed for DROP TABLESPACE, because DROP TABLESPACE would be refused if tables existed in the tablespace, and a previous DROP TABLE would have already removed the AHI entries. */ btr_search_drop_page_hash_when_freed( page_id_t(space_id, *arr), page_size); } } /******************************************************************//** When doing a DROP TABLE/DISCARD TABLESPACE we have to drop all page hash index entries belonging to that table. This function tries to do that in batch. Note that this is a 'best effort' attempt and does not guarantee that ALL hash entries will be removed. */ static void buf_LRU_drop_page_hash_for_tablespace( /*==================================*/ buf_pool_t* buf_pool, /*!< in: buffer pool instance */ ulint id) /*!< in: space id */ { bool found; const page_size_t page_size(fil_space_get_page_size(id, &found)); if (!found) { /* Somehow, the tablespace does not exist. Nothing to drop. */ ut_ad(0); return; } ulint* page_arr = static_cast(ut_malloc_nokey( sizeof(ulint) * BUF_LRU_DROP_SEARCH_SIZE)); ulint num_entries = 0; buf_pool_mutex_enter(buf_pool); scan_again: for (buf_page_t* bpage = UT_LIST_GET_LAST(buf_pool->LRU); bpage != NULL; /* No op */) { buf_page_t* prev_bpage = UT_LIST_GET_PREV(LRU, bpage); ut_a(buf_page_in_file(bpage)); if (buf_page_get_state(bpage) != BUF_BLOCK_FILE_PAGE || bpage->id.space() != id || bpage->io_fix != BUF_IO_NONE) { /* Compressed pages are never hashed. Skip blocks of other tablespaces. Skip I/O-fixed blocks (to be dealt with later). */ next_page: bpage = prev_bpage; continue; } buf_block_t* block = reinterpret_cast(bpage); mutex_enter(&block->mutex); /* This debug check uses a dirty read that could theoretically cause false positives while buf_pool_clear_hash_index() is executing. (Other conflicting access paths to the adaptive hash index should not be possible, because when a tablespace is being discarded or dropped, there must be no concurrect access to the contained tables.) */ assert_block_ahi_valid(block); bool skip = bpage->buf_fix_count > 0 || !block->index; mutex_exit(&block->mutex); if (skip) { /* Skip this block, because there are no adaptive hash index entries pointing to it, or because we cannot drop them due to the buffer-fix. */ goto next_page; } /* Store the page number so that we can drop the hash index in a batch later. */ page_arr[num_entries] = bpage->id.page_no(); ut_a(num_entries < BUF_LRU_DROP_SEARCH_SIZE); ++num_entries; if (num_entries < BUF_LRU_DROP_SEARCH_SIZE) { goto next_page; } /* Array full. We release the buf_pool->mutex to obey the latching order. */ buf_pool_mutex_exit(buf_pool); buf_LRU_drop_page_hash_batch( id, page_size, page_arr, num_entries); num_entries = 0; buf_pool_mutex_enter(buf_pool); /* Note that we released the buf_pool mutex above after reading the prev_bpage during processing of a page_hash_batch (i.e.: when the array was full). Because prev_bpage could belong to a compressed-only block, it may have been relocated, and thus the pointer cannot be trusted. Because bpage is of type buf_block_t, it is safe to dereference. bpage can change in the LRU list. This is OK because this function is a 'best effort' to drop as many search hash entries as possible and it does not guarantee that ALL such entries will be dropped. */ /* If, however, bpage has been removed from LRU list to the free list then we should restart the scan. bpage->state is protected by buf_pool mutex. */ if (bpage != NULL && buf_page_get_state(bpage) != BUF_BLOCK_FILE_PAGE) { goto scan_again; } } buf_pool_mutex_exit(buf_pool); /* Drop any remaining batch of search hashed pages. */ buf_LRU_drop_page_hash_batch(id, page_size, page_arr, num_entries); ut_free(page_arr); } #endif /* BTR_CUR_HASH_ADAPT */ /******************************************************************//** While flushing (or removing dirty) pages from a tablespace we don't want to hog the CPU and resources. Release the buffer pool and block mutex and try to force a context switch. Then reacquire the same mutexes. The current page is "fixed" before the release of the mutexes and then "unfixed" again once we have reacquired the mutexes. */ static void buf_flush_yield( /*============*/ buf_pool_t* buf_pool, /*!< in/out: buffer pool instance */ buf_page_t* bpage) /*!< in/out: current page */ { BPageMutex* block_mutex; ut_ad(buf_pool_mutex_own(buf_pool)); ut_ad(buf_page_in_file(bpage)); block_mutex = buf_page_get_mutex(bpage); mutex_enter(block_mutex); /* "Fix" the block so that the position cannot be changed after we release the buffer pool and block mutexes. */ buf_page_set_sticky(bpage); /* Now it is safe to release the buf_pool->mutex. */ buf_pool_mutex_exit(buf_pool); mutex_exit(block_mutex); /* Try and force a context switch. */ os_thread_yield(); buf_pool_mutex_enter(buf_pool); mutex_enter(block_mutex); /* "Unfix" the block now that we have both the buffer pool and block mutex again. */ buf_page_unset_sticky(bpage); mutex_exit(block_mutex); } /******************************************************************//** If we have hogged the resources for too long then release the buffer pool and flush list mutex and do a thread yield. Set the current page to "sticky" so that it is not relocated during the yield. @return true if yielded */ static MY_ATTRIBUTE((warn_unused_result)) bool buf_flush_try_yield( /*================*/ buf_pool_t* buf_pool, /*!< in/out: buffer pool instance */ buf_page_t* bpage, /*!< in/out: bpage to remove */ ulint processed) /*!< in: number of pages processed */ { /* Every BUF_LRU_DROP_SEARCH_SIZE iterations in the loop we release buf_pool->mutex to let other threads do their job but only if the block is not IO fixed. This ensures that the block stays in its position in the flush_list. */ if (bpage != NULL && processed >= BUF_LRU_DROP_SEARCH_SIZE && buf_page_get_io_fix(bpage) == BUF_IO_NONE) { buf_flush_list_mutex_exit(buf_pool); /* Release the buffer pool and block mutex to give the other threads a go. */ buf_flush_yield(buf_pool, bpage); buf_flush_list_mutex_enter(buf_pool); /* Should not have been removed from the flush list during the yield. However, this check is not sufficient to catch a remove -> add. */ ut_ad(bpage->in_flush_list); return(true); } return(false); } /******************************************************************//** Removes a single page from a given tablespace inside a specific buffer pool instance. @return true if page was removed. */ static MY_ATTRIBUTE((warn_unused_result)) bool buf_flush_or_remove_page( /*=====================*/ buf_pool_t* buf_pool, /*!< in/out: buffer pool instance */ buf_page_t* bpage, /*!< in/out: bpage to remove */ bool flush) /*!< in: flush to disk if true but don't remove else remove without flushing to disk */ { ut_ad(buf_pool_mutex_own(buf_pool)); ut_ad(buf_flush_list_mutex_own(buf_pool)); /* bpage->space and bpage->io_fix are protected by buf_pool->mutex and block_mutex. It is safe to check them while holding buf_pool->mutex only. */ if (buf_page_get_io_fix(bpage) != BUF_IO_NONE) { /* We cannot remove this page during this scan yet; maybe the system is currently reading it in, or flushing the modifications to the file */ return(false); } BPageMutex* block_mutex; bool processed = false; block_mutex = buf_page_get_mutex(bpage); /* We have to release the flush_list_mutex to obey the latching order. We are however guaranteed that the page will stay in the flush_list and won't be relocated because buf_flush_remove() and buf_flush_relocate_on_flush_list() need buf_pool->mutex as well. */ buf_flush_list_mutex_exit(buf_pool); mutex_enter(block_mutex); ut_ad(bpage->oldest_modification != 0); if (!flush) { buf_flush_remove(bpage); mutex_exit(block_mutex); processed = true; } else if (buf_flush_ready_for_flush(bpage, BUF_FLUSH_SINGLE_PAGE)) { /* The following call will release the buffer pool and block mutex. */ processed = buf_flush_page( buf_pool, bpage, BUF_FLUSH_SINGLE_PAGE, false); if (processed) { /* Wake possible simulated aio thread to actually post the writes to the operating system */ os_aio_simulated_wake_handler_threads(); buf_pool_mutex_enter(buf_pool); } else { mutex_exit(block_mutex); } } else { mutex_exit(block_mutex); } buf_flush_list_mutex_enter(buf_pool); ut_ad(!mutex_own(block_mutex)); ut_ad(buf_pool_mutex_own(buf_pool)); return(processed); } /******************************************************************//** Remove all dirty pages belonging to a given tablespace inside a specific buffer pool instance when we are deleting the data file(s) of that tablespace. The pages still remain a part of LRU and are evicted from the list as they age towards the tail of the LRU. @retval DB_SUCCESS if all freed @retval DB_FAIL if not all freed @retval DB_INTERRUPTED if the transaction was interrupted */ static MY_ATTRIBUTE((warn_unused_result)) dberr_t buf_flush_or_remove_pages( /*======================*/ buf_pool_t* buf_pool, /*!< buffer pool instance */ ulint id, /*!< in: target space id for which to remove or flush pages */ FlushObserver* observer, /*!< in: flush observer */ bool flush, /*!< in: flush to disk if true but don't remove else remove without flushing to disk */ const trx_t* trx) /*!< to check if the operation must be interrupted, can be 0 */ { buf_page_t* prev; buf_page_t* bpage; ulint processed = 0; buf_flush_list_mutex_enter(buf_pool); rescan: bool all_freed = true; for (bpage = UT_LIST_GET_LAST(buf_pool->flush_list); bpage != NULL; bpage = prev) { ut_a(buf_page_in_file(bpage)); /* Save the previous link because once we free the page we can't rely on the links. */ prev = UT_LIST_GET_PREV(list, bpage); /* If flush observer is NULL, flush page for space id, or flush page for flush observer. */ if ((observer != NULL && observer != bpage->flush_observer) || (observer == NULL && id != bpage->id.space())) { /* Skip this block, as it does not belong to the target space. */ } else if (!buf_flush_or_remove_page(buf_pool, bpage, flush)) { /* Remove was unsuccessful, we have to try again by scanning the entire list from the end. This also means that we never released the buf_pool mutex. Therefore we can trust the prev pointer. buf_flush_or_remove_page() released the flush list mutex but not the buf_pool mutex. Therefore it is possible that a new page was added to the flush list. For example, in case where we are at the head of the flush list and prev == NULL. That is OK because we have the tablespace quiesced and no new pages for this space-id should enter flush_list. This is because the only callers of this function are DROP TABLE and FLUSH TABLE FOR EXPORT. We know that we'll have to do at least one more scan but we don't break out of loop here and try to do as much work as we can in this iteration. */ all_freed = false; } else if (flush) { /* The processing was successful. And during the processing we have released the buf_pool mutex when calling buf_page_flush(). We cannot trust prev pointer. */ goto rescan; } ++processed; /* Yield if we have hogged the CPU and mutexes for too long. */ if (buf_flush_try_yield(buf_pool, prev, processed)) { /* Reset the batch size counter if we had to yield. */ processed = 0; } /* The check for trx is interrupted is expensive, we want to check every N iterations. */ if (!processed && trx && trx_is_interrupted(trx)) { if (trx->flush_observer != NULL) { if (flush) { trx->flush_observer->interrupted(); } else { /* We should remove all pages with the the flush observer. */ continue; } } buf_flush_list_mutex_exit(buf_pool); return(DB_INTERRUPTED); } } buf_flush_list_mutex_exit(buf_pool); return(all_freed ? DB_SUCCESS : DB_FAIL); } /******************************************************************//** Remove or flush all the dirty pages that belong to a given tablespace inside a specific buffer pool instance. The pages will remain in the LRU list and will be evicted from the LRU list as they age and move towards the tail of the LRU list. */ static void buf_flush_dirty_pages( /*==================*/ buf_pool_t* buf_pool, /*!< buffer pool instance */ ulint id, /*!< in: space id */ FlushObserver* observer, /*!< in: flush observer */ bool flush, /*!< in: flush to disk if true otherwise remove the pages without flushing */ const trx_t* trx) /*!< to check if the operation must be interrupted */ { dberr_t err; do { buf_pool_mutex_enter(buf_pool); err = buf_flush_or_remove_pages( buf_pool, id, observer, flush, trx); buf_pool_mutex_exit(buf_pool); ut_ad(buf_flush_validate(buf_pool)); if (err == DB_FAIL) { os_thread_sleep(2000); } if (err == DB_INTERRUPTED && observer != NULL) { ut_a(flush); flush = false; err = DB_FAIL; } /* DB_FAIL is a soft error, it means that the task wasn't completed, needs to be retried. */ ut_ad(buf_flush_validate(buf_pool)); } while (err == DB_FAIL); ut_ad(err == DB_INTERRUPTED || buf_pool_get_dirty_pages_count(buf_pool, id, observer) == 0); } /******************************************************************//** Remove all pages that belong to a given tablespace inside a specific buffer pool instance when we are DISCARDing the tablespace. */ static void buf_LRU_remove_all_pages( /*=====================*/ buf_pool_t* buf_pool, /*!< buffer pool instance */ ulint id) /*!< in: space id */ { buf_page_t* bpage; ibool all_freed; scan_again: buf_pool_mutex_enter(buf_pool); all_freed = TRUE; for (bpage = UT_LIST_GET_LAST(buf_pool->LRU); bpage != NULL; /* No op */) { rw_lock_t* hash_lock; buf_page_t* prev_bpage; BPageMutex* block_mutex; ut_a(buf_page_in_file(bpage)); ut_ad(bpage->in_LRU_list); prev_bpage = UT_LIST_GET_PREV(LRU, bpage); /* bpage->id.space() and bpage->io_fix are protected by buf_pool->mutex and the block_mutex. It is safe to check them while holding buf_pool->mutex only. */ if (bpage->id.space() != id) { /* Skip this block, as it does not belong to the space that is being invalidated. */ goto next_page; } else if (buf_page_get_io_fix(bpage) != BUF_IO_NONE) { /* We cannot remove this page during this scan yet; maybe the system is currently reading it in, or flushing the modifications to the file */ all_freed = FALSE; goto next_page; } else { hash_lock = buf_page_hash_lock_get(buf_pool, bpage->id); rw_lock_x_lock(hash_lock); block_mutex = buf_page_get_mutex(bpage); mutex_enter(block_mutex); if (bpage->buf_fix_count > 0) { mutex_exit(block_mutex); rw_lock_x_unlock(hash_lock); /* We cannot remove this page during this scan yet; maybe the system is currently reading it in, or flushing the modifications to the file */ all_freed = FALSE; goto next_page; } } ut_ad(mutex_own(block_mutex)); DBUG_PRINT("ib_buf", ("evict page %u:%u" " state %u", bpage->id.space(), bpage->id.page_no(), bpage->state)); #ifdef BTR_CUR_HASH_ADAPT if (buf_page_get_state(bpage) != BUF_BLOCK_FILE_PAGE) { /* Do nothing, because the adaptive hash index covers uncompressed pages only. */ } else if (((buf_block_t*) bpage)->index) { buf_pool_mutex_exit(buf_pool); rw_lock_x_unlock(hash_lock); mutex_exit(block_mutex); /* Note that the following call will acquire and release block->lock X-latch. Note that the table cannot be evicted during the execution of ALTER TABLE...DISCARD TABLESPACE because MySQL is keeping the table handle open. */ btr_search_drop_page_hash_when_freed( bpage->id, bpage->size); goto scan_again; } else { /* This debug check uses a dirty read that could theoretically cause false positives while buf_pool_clear_hash_index() is executing, if the writes to block->index=NULL and block->n_pointers=0 are reordered. (Other conflicting access paths to the adaptive hash index should not be possible, because when a tablespace is being discarded or dropped, there must be no concurrect access to the contained tables.) */ assert_block_ahi_empty((buf_block_t*) bpage); } #endif /* BTR_CUR_HASH_ADAPT */ if (bpage->oldest_modification != 0) { buf_flush_remove(bpage); } ut_ad(!bpage->in_flush_list); /* Remove from the LRU list. */ if (buf_LRU_block_remove_hashed(bpage, true)) { buf_LRU_block_free_hashed_page((buf_block_t*) bpage); } else { ut_ad(block_mutex == &buf_pool->zip_mutex); } ut_ad(!mutex_own(block_mutex)); /* buf_LRU_block_remove_hashed() releases the hash_lock */ ut_ad(!rw_lock_own(hash_lock, RW_LOCK_X)); ut_ad(!rw_lock_own(hash_lock, RW_LOCK_S)); next_page: bpage = prev_bpage; } buf_pool_mutex_exit(buf_pool); if (!all_freed) { os_thread_sleep(20000); goto scan_again; } } /******************************************************************//** Remove pages belonging to a given tablespace inside a specific buffer pool instance when we are deleting the data file(s) of that tablespace. The pages still remain a part of LRU and are evicted from the list as they age towards the tail of the LRU only if buf_remove is BUF_REMOVE_FLUSH_NO_WRITE. */ static void buf_LRU_remove_pages( /*=================*/ buf_pool_t* buf_pool, /*!< buffer pool instance */ ulint id, /*!< in: space id */ buf_remove_t buf_remove, /*!< in: remove or flush strategy */ const trx_t* trx) /*!< to check if the operation must be interrupted */ { FlushObserver* observer = (trx == NULL) ? NULL : trx->flush_observer; switch (buf_remove) { case BUF_REMOVE_ALL_NO_WRITE: buf_LRU_remove_all_pages(buf_pool, id); break; case BUF_REMOVE_FLUSH_NO_WRITE: /* Pass trx as NULL to avoid interruption check. */ buf_flush_dirty_pages(buf_pool, id, observer, false, NULL); break; case BUF_REMOVE_FLUSH_WRITE: buf_flush_dirty_pages(buf_pool, id, observer, true, trx); if (observer == NULL) { /* Ensure that all asynchronous IO is completed. */ os_aio_wait_until_no_pending_writes(); fil_flush(id); } break; } } /******************************************************************//** Flushes all dirty pages or removes all pages belonging to a given tablespace. A PROBLEM: if readahead is being started, what guarantees that it will not try to read in pages after this operation has completed? */ void buf_LRU_flush_or_remove_pages( /*==========================*/ ulint id, /*!< in: space id */ buf_remove_t buf_remove, /*!< in: remove or flush strategy */ const trx_t* trx) /*!< to check if the operation must be interrupted */ { ulint i; /* Before we attempt to drop pages one by one we first attempt to drop page hash index entries in batches to make it more efficient. The batching attempt is a best effort attempt and does not guarantee that all pages hash entries will be dropped. We get rid of remaining page hash entries one by one below. */ for (i = 0; i < srv_buf_pool_instances; i++) { buf_pool_t* buf_pool; buf_pool = buf_pool_from_array(i); #ifdef BTR_CUR_HASH_ADAPT switch (buf_remove) { case BUF_REMOVE_ALL_NO_WRITE: buf_LRU_drop_page_hash_for_tablespace(buf_pool, id); break; case BUF_REMOVE_FLUSH_NO_WRITE: /* It is a DROP TABLE for a single table tablespace. No AHI entries exist because we already dealt with them when freeing up extents. */ case BUF_REMOVE_FLUSH_WRITE: /* We allow read-only queries against the table, there is no need to drop the AHI entries. */ break; } #endif /* BTR_CUR_HASH_ADAPT */ buf_LRU_remove_pages(buf_pool, id, buf_remove, trx); } } #if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG /********************************************************************//** Insert a compressed block into buf_pool->zip_clean in the LRU order. */ void buf_LRU_insert_zip_clean( /*=====================*/ buf_page_t* bpage) /*!< in: pointer to the block in question */ { buf_pool_t* buf_pool = buf_pool_from_bpage(bpage); ut_ad(buf_pool_mutex_own(buf_pool)); ut_ad(buf_page_get_state(bpage) == BUF_BLOCK_ZIP_PAGE); /* Find the first successor of bpage in the LRU list that is in the zip_clean list. */ buf_page_t* b = bpage; do { b = UT_LIST_GET_NEXT(LRU, b); } while (b && buf_page_get_state(b) != BUF_BLOCK_ZIP_PAGE); /* Insert bpage before b, i.e., after the predecessor of b. */ if (b != NULL) { b = UT_LIST_GET_PREV(list, b); } if (b != NULL) { UT_LIST_INSERT_AFTER(buf_pool->zip_clean, b, bpage); } else { UT_LIST_ADD_FIRST(buf_pool->zip_clean, bpage); } } #endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */ /******************************************************************//** Try to free an uncompressed page of a compressed block from the unzip LRU list. The compressed page is preserved, and it need not be clean. @return true if freed */ static bool buf_LRU_free_from_unzip_LRU_list( /*=============================*/ buf_pool_t* buf_pool, /*!< in: buffer pool instance */ bool scan_all) /*!< in: scan whole LRU list if true, otherwise scan only srv_LRU_scan_depth / 2 blocks. */ { ut_ad(buf_pool_mutex_own(buf_pool)); if (!buf_LRU_evict_from_unzip_LRU(buf_pool)) { return(false); } ulint scanned = 0; bool freed = false; for (buf_block_t* block = UT_LIST_GET_LAST(buf_pool->unzip_LRU); block != NULL && !freed && (scan_all || scanned < srv_LRU_scan_depth); ++scanned) { buf_block_t* prev_block; prev_block = UT_LIST_GET_PREV(unzip_LRU, block); ut_ad(buf_block_get_state(block) == BUF_BLOCK_FILE_PAGE); ut_ad(block->in_unzip_LRU_list); ut_ad(block->page.in_LRU_list); freed = buf_LRU_free_page(&block->page, false); block = prev_block; } if (scanned) { MONITOR_INC_VALUE_CUMULATIVE( MONITOR_LRU_UNZIP_SEARCH_SCANNED, MONITOR_LRU_UNZIP_SEARCH_SCANNED_NUM_CALL, MONITOR_LRU_UNZIP_SEARCH_SCANNED_PER_CALL, scanned); } return(freed); } /******************************************************************//** Try to free a clean page from the common LRU list. @return true if freed */ static bool buf_LRU_free_from_common_LRU_list( /*==============================*/ buf_pool_t* buf_pool, /*!< in: buffer pool instance */ bool scan_all) /*!< in: scan whole LRU list if true, otherwise scan only up to BUF_LRU_SEARCH_SCAN_THRESHOLD */ { ut_ad(buf_pool_mutex_own(buf_pool)); ulint scanned = 0; bool freed = false; for (buf_page_t* bpage = buf_pool->lru_scan_itr.start(); bpage != NULL && !freed && (scan_all || scanned < BUF_LRU_SEARCH_SCAN_THRESHOLD); ++scanned, bpage = buf_pool->lru_scan_itr.get()) { buf_page_t* prev = UT_LIST_GET_PREV(LRU, bpage); BPageMutex* mutex = buf_page_get_mutex(bpage); buf_pool->lru_scan_itr.set(prev); mutex_enter(mutex); ut_ad(buf_page_in_file(bpage)); ut_ad(bpage->in_LRU_list); unsigned accessed = buf_page_is_accessed(bpage); if (buf_flush_ready_for_replace(bpage)) { mutex_exit(mutex); freed = buf_LRU_free_page(bpage, true); } else { mutex_exit(mutex); } if (freed && !accessed) { /* Keep track of pages that are evicted without ever being accessed. This gives us a measure of the effectiveness of readahead */ ++buf_pool->stat.n_ra_pages_evicted; } ut_ad(buf_pool_mutex_own(buf_pool)); ut_ad(!mutex_own(mutex)); } if (scanned) { MONITOR_INC_VALUE_CUMULATIVE( MONITOR_LRU_SEARCH_SCANNED, MONITOR_LRU_SEARCH_SCANNED_NUM_CALL, MONITOR_LRU_SEARCH_SCANNED_PER_CALL, scanned); } return(freed); } /******************************************************************//** Try to free a replaceable block. @return true if found and freed */ bool buf_LRU_scan_and_free_block( /*========================*/ buf_pool_t* buf_pool, /*!< in: buffer pool instance */ bool scan_all) /*!< in: scan whole LRU list if true, otherwise scan only BUF_LRU_SEARCH_SCAN_THRESHOLD blocks. */ { ut_ad(buf_pool_mutex_own(buf_pool)); return(buf_LRU_free_from_unzip_LRU_list(buf_pool, scan_all) || buf_LRU_free_from_common_LRU_list(buf_pool, scan_all)); } /******************************************************************//** Returns TRUE if less than 25 % of the buffer pool in any instance is available. This can be used in heuristics to prevent huge transactions eating up the whole buffer pool for their locks. @return TRUE if less than 25 % of buffer pool left */ ibool buf_LRU_buf_pool_running_out(void) /*==============================*/ { ibool ret = FALSE; for (ulint i = 0; i < srv_buf_pool_instances && !ret; i++) { buf_pool_t* buf_pool; buf_pool = buf_pool_from_array(i); buf_pool_mutex_enter(buf_pool); if (!recv_recovery_is_on() && UT_LIST_GET_LEN(buf_pool->free) + UT_LIST_GET_LEN(buf_pool->LRU) < ut_min(buf_pool->curr_size, buf_pool->old_size) / 4) { ret = TRUE; } buf_pool_mutex_exit(buf_pool); } return(ret); } /******************************************************************//** Returns a free block from the buf_pool. The block is taken off the free list. If it is empty, returns NULL. @return a free control block, or NULL if the buf_block->free list is empty */ buf_block_t* buf_LRU_get_free_only( /*==================*/ buf_pool_t* buf_pool) { buf_block_t* block; ut_ad(buf_pool_mutex_own(buf_pool)); block = reinterpret_cast( UT_LIST_GET_FIRST(buf_pool->free)); while (block != NULL) { ut_ad(block->page.in_free_list); ut_d(block->page.in_free_list = FALSE); ut_ad(!block->page.in_flush_list); ut_ad(!block->page.in_LRU_list); ut_a(!buf_page_in_file(&block->page)); UT_LIST_REMOVE(buf_pool->free, &block->page); if (buf_pool->curr_size >= buf_pool->old_size || UT_LIST_GET_LEN(buf_pool->withdraw) >= buf_pool->withdraw_target || !buf_block_will_withdrawn(buf_pool, block)) { /* found valid free block */ buf_page_mutex_enter(block); /* No adaptive hash index entries may point to a free block. */ assert_block_ahi_empty(block); buf_block_set_state(block, BUF_BLOCK_READY_FOR_USE); UNIV_MEM_ALLOC(block->frame, UNIV_PAGE_SIZE); ut_ad(buf_pool_from_block(block) == buf_pool); buf_page_mutex_exit(block); break; } /* This should be withdrawn */ UT_LIST_ADD_LAST( buf_pool->withdraw, &block->page); ut_d(block->in_withdraw_list = TRUE); block = reinterpret_cast( UT_LIST_GET_FIRST(buf_pool->free)); } return(block); } /******************************************************************//** Checks how much of buf_pool is occupied by non-data objects like AHI, lock heaps etc. Depending on the size of non-data objects this function will either assert or issue a warning and switch on the status monitor. */ static void buf_LRU_check_size_of_non_data_objects( /*===================================*/ const buf_pool_t* buf_pool) /*!< in: buffer pool instance */ { ut_ad(buf_pool_mutex_own(buf_pool)); if (!recv_recovery_is_on() && buf_pool->curr_size == buf_pool->old_size && UT_LIST_GET_LEN(buf_pool->free) + UT_LIST_GET_LEN(buf_pool->LRU) < buf_pool->curr_size / 20) { ib::fatal() << "Over 95 percent of the buffer pool is" " occupied by lock heaps" #ifdef BTR_CUR_HASH_ADAPT " or the adaptive hash index!" #endif /* BTR_CUR_HASH_ADAPT */ " Check that your transactions do not set too many" " row locks, or review if" " innodb_buffer_pool_size=" << (buf_pool->curr_size >> (20 - UNIV_PAGE_SIZE_SHIFT)) << "M could be bigger."; } else if (!recv_recovery_is_on() && buf_pool->curr_size == buf_pool->old_size && (UT_LIST_GET_LEN(buf_pool->free) + UT_LIST_GET_LEN(buf_pool->LRU)) < buf_pool->curr_size / 3) { if (!buf_lru_switched_on_innodb_mon) { /* Over 67 % of the buffer pool is occupied by lock heaps or the adaptive hash index. This may be a memory leak! */ ib::warn() << "Over 67 percent of the buffer pool is" " occupied by lock heaps" #ifdef BTR_CUR_HASH_ADAPT " or the adaptive hash index!" #endif /* BTR_CUR_HASH_ADAPT */ " Check that your transactions do not" " set too many row locks." " innodb_buffer_pool_size=" << (buf_pool->curr_size >> (20 - UNIV_PAGE_SIZE_SHIFT)) << "M." " Starting the InnoDB Monitor to print" " diagnostics."; buf_lru_switched_on_innodb_mon = true; srv_print_innodb_monitor = TRUE; os_event_set(srv_monitor_event); } } else if (buf_lru_switched_on_innodb_mon) { /* Switch off the InnoDB Monitor; this is a simple way to stop the monitor if the situation becomes less urgent, but may also surprise users if the user also switched on the monitor! */ buf_lru_switched_on_innodb_mon = false; srv_print_innodb_monitor = FALSE; } } /******************************************************************//** Returns a free block from the buf_pool. The block is taken off the free list. If free list is empty, blocks are moved from the end of the LRU list to the free list. This function is called from a user thread when it needs a clean block to read in a page. Note that we only ever get a block from the free list. Even when we flush a page or find a page in LRU scan we put it to free list to be used. * iteration 0: * get a block from free list, success:done * if buf_pool->try_LRU_scan is set * scan LRU up to srv_LRU_scan_depth to find a clean block * the above will put the block on free list * success:retry the free list * flush one dirty page from tail of LRU to disk * the above will put the block on free list * success: retry the free list * iteration 1: * same as iteration 0 except: * scan whole LRU list * scan LRU list even if buf_pool->try_LRU_scan is not set * iteration > 1: * same as iteration 1 but sleep 10ms @return the free control block, in state BUF_BLOCK_READY_FOR_USE */ buf_block_t* buf_LRU_get_free_block( /*===================*/ buf_pool_t* buf_pool) /*!< in/out: buffer pool instance */ { buf_block_t* block = NULL; bool freed = false; ulint n_iterations = 0; ulint flush_failures = 0; bool mon_value_was = false; bool started_monitor = false; MONITOR_INC(MONITOR_LRU_GET_FREE_SEARCH); loop: buf_pool_mutex_enter(buf_pool); buf_LRU_check_size_of_non_data_objects(buf_pool); /* If there is a block in the free list, take it */ block = buf_LRU_get_free_only(buf_pool); if (block != NULL) { buf_pool_mutex_exit(buf_pool); ut_ad(buf_pool_from_block(block) == buf_pool); memset(&block->page.zip, 0, sizeof block->page.zip); if (started_monitor) { srv_print_innodb_monitor = static_cast(mon_value_was); } block->skip_flush_check = false; block->page.flush_observer = NULL; return(block); } MONITOR_INC( MONITOR_LRU_GET_FREE_LOOPS ); freed = false; if (buf_pool->try_LRU_scan || n_iterations > 0) { /* If no block was in the free list, search from the end of the LRU list and try to free a block there. If we are doing for the first time we'll scan only tail of the LRU list otherwise we scan the whole LRU list. */ freed = buf_LRU_scan_and_free_block( buf_pool, n_iterations > 0); if (!freed && n_iterations == 0) { /* Tell other threads that there is no point in scanning the LRU list. This flag is set to TRUE again when we flush a batch from this buffer pool. */ buf_pool->try_LRU_scan = FALSE; /* Also tell the page_cleaner thread that there is work for it to do. */ os_event_set(buf_flush_event); } } buf_pool_mutex_exit(buf_pool); if (freed) { goto loop; } if (n_iterations > 20 && srv_buf_pool_old_size == srv_buf_pool_size) { ib::warn() << "Difficult to find free blocks in the buffer pool" " (" << n_iterations << " search iterations)! " << flush_failures << " failed attempts to" " flush a page! Consider increasing the buffer pool" " size. It is also possible that in your Unix version" " fsync is very slow, or completely frozen inside" " the OS kernel. Then upgrading to a newer version" " of your operating system may help. Look at the" " number of fsyncs in diagnostic info below." " Pending flushes (fsync) log: " << fil_n_pending_log_flushes << "; buffer pool: " << fil_n_pending_tablespace_flushes << ". " << os_n_file_reads << " OS file reads, " << os_n_file_writes << " OS file writes, " << os_n_fsyncs << " OS fsyncs. Starting InnoDB Monitor to print" " further diagnostics to the standard output."; mon_value_was = srv_print_innodb_monitor; started_monitor = true; srv_print_innodb_monitor = true; os_event_set(srv_monitor_event); } /* If we have scanned the whole LRU and still are unable to find a free block then we should sleep here to let the page_cleaner do an LRU batch for us. */ if (!srv_read_only_mode) { os_event_set(buf_flush_event); } if (n_iterations > 1) { MONITOR_INC( MONITOR_LRU_GET_FREE_WAITS ); os_thread_sleep(10000); } /* No free block was found: try to flush the LRU list. This call will flush one page from the LRU and put it on the free list. That means that the free block is up for grabs for all user threads. TODO: A more elegant way would have been to return the freed up block to the caller here but the code that deals with removing the block from page_hash and LRU_list is fairly involved (particularly in case of compressed pages). We can do that in a separate patch sometime in future. */ if (!buf_flush_single_page_from_LRU(buf_pool)) { MONITOR_INC(MONITOR_LRU_SINGLE_FLUSH_FAILURE_COUNT); ++flush_failures; } srv_stats.buf_pool_wait_free.add(n_iterations, 1); n_iterations++; goto loop; } /*******************************************************************//** Moves the LRU_old pointer so that the length of the old blocks list is inside the allowed limits. */ UNIV_INLINE void buf_LRU_old_adjust_len( /*===================*/ buf_pool_t* buf_pool) /*!< in: buffer pool instance */ { ulint old_len; ulint new_len; ut_a(buf_pool->LRU_old); ut_ad(buf_pool_mutex_own(buf_pool)); ut_ad(buf_pool->LRU_old_ratio >= BUF_LRU_OLD_RATIO_MIN); ut_ad(buf_pool->LRU_old_ratio <= BUF_LRU_OLD_RATIO_MAX); #if BUF_LRU_OLD_RATIO_MIN * BUF_LRU_OLD_MIN_LEN <= BUF_LRU_OLD_RATIO_DIV * (BUF_LRU_OLD_TOLERANCE + 5) # error "BUF_LRU_OLD_RATIO_MIN * BUF_LRU_OLD_MIN_LEN <= BUF_LRU_OLD_RATIO_DIV * (BUF_LRU_OLD_TOLERANCE + 5)" #endif #ifdef UNIV_LRU_DEBUG /* buf_pool->LRU_old must be the first item in the LRU list whose "old" flag is set. */ ut_a(buf_pool->LRU_old->old); ut_a(!UT_LIST_GET_PREV(LRU, buf_pool->LRU_old) || !UT_LIST_GET_PREV(LRU, buf_pool->LRU_old)->old); ut_a(!UT_LIST_GET_NEXT(LRU, buf_pool->LRU_old) || UT_LIST_GET_NEXT(LRU, buf_pool->LRU_old)->old); #endif /* UNIV_LRU_DEBUG */ old_len = buf_pool->LRU_old_len; new_len = ut_min(UT_LIST_GET_LEN(buf_pool->LRU) * buf_pool->LRU_old_ratio / BUF_LRU_OLD_RATIO_DIV, UT_LIST_GET_LEN(buf_pool->LRU) - (BUF_LRU_OLD_TOLERANCE + BUF_LRU_NON_OLD_MIN_LEN)); for (;;) { buf_page_t* LRU_old = buf_pool->LRU_old; ut_a(LRU_old); ut_ad(LRU_old->in_LRU_list); #ifdef UNIV_LRU_DEBUG ut_a(LRU_old->old); #endif /* UNIV_LRU_DEBUG */ /* Update the LRU_old pointer if necessary */ if (old_len + BUF_LRU_OLD_TOLERANCE < new_len) { buf_pool->LRU_old = LRU_old = UT_LIST_GET_PREV( LRU, LRU_old); #ifdef UNIV_LRU_DEBUG ut_a(!LRU_old->old); #endif /* UNIV_LRU_DEBUG */ old_len = ++buf_pool->LRU_old_len; buf_page_set_old(LRU_old, TRUE); } else if (old_len > new_len + BUF_LRU_OLD_TOLERANCE) { buf_pool->LRU_old = UT_LIST_GET_NEXT(LRU, LRU_old); old_len = --buf_pool->LRU_old_len; buf_page_set_old(LRU_old, FALSE); } else { return; } } } /*******************************************************************//** Initializes the old blocks pointer in the LRU list. This function should be called when the LRU list grows to BUF_LRU_OLD_MIN_LEN length. */ static void buf_LRU_old_init( /*=============*/ buf_pool_t* buf_pool) { ut_ad(buf_pool_mutex_own(buf_pool)); ut_a(UT_LIST_GET_LEN(buf_pool->LRU) == BUF_LRU_OLD_MIN_LEN); /* We first initialize all blocks in the LRU list as old and then use the adjust function to move the LRU_old pointer to the right position */ for (buf_page_t* bpage = UT_LIST_GET_LAST(buf_pool->LRU); bpage != NULL; bpage = UT_LIST_GET_PREV(LRU, bpage)) { ut_ad(bpage->in_LRU_list); ut_ad(buf_page_in_file(bpage)); /* This loop temporarily violates the assertions of buf_page_set_old(). */ bpage->old = TRUE; } buf_pool->LRU_old = UT_LIST_GET_FIRST(buf_pool->LRU); buf_pool->LRU_old_len = UT_LIST_GET_LEN(buf_pool->LRU); buf_LRU_old_adjust_len(buf_pool); } /******************************************************************//** Remove a block from the unzip_LRU list if it belonged to the list. */ static void buf_unzip_LRU_remove_block_if_needed( /*=================================*/ buf_page_t* bpage) /*!< in/out: control block */ { buf_pool_t* buf_pool = buf_pool_from_bpage(bpage); ut_ad(buf_page_in_file(bpage)); ut_ad(buf_pool_mutex_own(buf_pool)); if (buf_page_belongs_to_unzip_LRU(bpage)) { buf_block_t* block = reinterpret_cast(bpage); ut_ad(block->in_unzip_LRU_list); ut_d(block->in_unzip_LRU_list = FALSE); UT_LIST_REMOVE(buf_pool->unzip_LRU, block); } } /******************************************************************//** Adjust LRU hazard pointers if needed. */ void buf_LRU_adjust_hp( /*==============*/ buf_pool_t* buf_pool,/*!< in: buffer pool instance */ const buf_page_t* bpage) /*!< in: control block */ { buf_pool->lru_hp.adjust(bpage); buf_pool->lru_scan_itr.adjust(bpage); buf_pool->single_scan_itr.adjust(bpage); } /******************************************************************//** Removes a block from the LRU list. */ UNIV_INLINE void buf_LRU_remove_block( /*=================*/ buf_page_t* bpage) /*!< in: control block */ { buf_pool_t* buf_pool = buf_pool_from_bpage(bpage); ut_ad(buf_pool_mutex_own(buf_pool)); ut_a(buf_page_in_file(bpage)); ut_ad(bpage->in_LRU_list); /* Important that we adjust the hazard pointers before removing bpage from the LRU list. */ buf_LRU_adjust_hp(buf_pool, bpage); /* If the LRU_old pointer is defined and points to just this block, move it backward one step */ if (bpage == buf_pool->LRU_old) { /* Below: the previous block is guaranteed to exist, because the LRU_old pointer is only allowed to differ by BUF_LRU_OLD_TOLERANCE from strict buf_pool->LRU_old_ratio/BUF_LRU_OLD_RATIO_DIV of the LRU list length. */ buf_page_t* prev_bpage = UT_LIST_GET_PREV(LRU, bpage); ut_a(prev_bpage); #ifdef UNIV_LRU_DEBUG ut_a(!prev_bpage->old); #endif /* UNIV_LRU_DEBUG */ buf_pool->LRU_old = prev_bpage; buf_page_set_old(prev_bpage, TRUE); buf_pool->LRU_old_len++; } /* Remove the block from the LRU list */ UT_LIST_REMOVE(buf_pool->LRU, bpage); ut_d(bpage->in_LRU_list = FALSE); buf_pool->stat.LRU_bytes -= bpage->size.physical(); buf_unzip_LRU_remove_block_if_needed(bpage); /* If the LRU list is so short that LRU_old is not defined, clear the "old" flags and return */ if (UT_LIST_GET_LEN(buf_pool->LRU) < BUF_LRU_OLD_MIN_LEN) { for (buf_page_t* bpage = UT_LIST_GET_FIRST(buf_pool->LRU); bpage != NULL; bpage = UT_LIST_GET_NEXT(LRU, bpage)) { /* This loop temporarily violates the assertions of buf_page_set_old(). */ bpage->old = FALSE; } buf_pool->LRU_old = NULL; buf_pool->LRU_old_len = 0; return; } ut_ad(buf_pool->LRU_old); /* Update the LRU_old_len field if necessary */ if (buf_page_is_old(bpage)) { buf_pool->LRU_old_len--; } /* Adjust the length of the old block list if necessary */ buf_LRU_old_adjust_len(buf_pool); } /******************************************************************//** Adds a block to the LRU list of decompressed zip pages. */ void buf_unzip_LRU_add_block( /*====================*/ buf_block_t* block, /*!< in: control block */ ibool old) /*!< in: TRUE if should be put to the end of the list, else put to the start */ { buf_pool_t* buf_pool = buf_pool_from_block(block); ut_ad(buf_pool_mutex_own(buf_pool)); ut_a(buf_page_belongs_to_unzip_LRU(&block->page)); ut_ad(!block->in_unzip_LRU_list); ut_d(block->in_unzip_LRU_list = TRUE); if (old) { UT_LIST_ADD_LAST(buf_pool->unzip_LRU, block); } else { UT_LIST_ADD_FIRST(buf_pool->unzip_LRU, block); } } /******************************************************************//** Adds a block to the LRU list. Please make sure that the page_size is already set when invoking the function, so that we can get correct page_size from the buffer page when adding a block into LRU */ UNIV_INLINE void buf_LRU_add_block_low( /*==================*/ buf_page_t* bpage, /*!< in: control block */ ibool old) /*!< in: TRUE if should be put to the old blocks in the LRU list, else put to the start; if the LRU list is very short, the block is added to the start, regardless of this parameter */ { buf_pool_t* buf_pool = buf_pool_from_bpage(bpage); ut_ad(buf_pool_mutex_own(buf_pool)); ut_a(buf_page_in_file(bpage)); ut_ad(!bpage->in_LRU_list); if (!old || (UT_LIST_GET_LEN(buf_pool->LRU) < BUF_LRU_OLD_MIN_LEN)) { UT_LIST_ADD_FIRST(buf_pool->LRU, bpage); bpage->freed_page_clock = buf_pool->freed_page_clock; } else { #ifdef UNIV_LRU_DEBUG /* buf_pool->LRU_old must be the first item in the LRU list whose "old" flag is set. */ ut_a(buf_pool->LRU_old->old); ut_a(!UT_LIST_GET_PREV(LRU, buf_pool->LRU_old) || !UT_LIST_GET_PREV(LRU, buf_pool->LRU_old)->old); ut_a(!UT_LIST_GET_NEXT(LRU, buf_pool->LRU_old) || UT_LIST_GET_NEXT(LRU, buf_pool->LRU_old)->old); #endif /* UNIV_LRU_DEBUG */ UT_LIST_INSERT_AFTER(buf_pool->LRU, buf_pool->LRU_old, bpage); buf_pool->LRU_old_len++; } ut_d(bpage->in_LRU_list = TRUE); incr_LRU_size_in_bytes(bpage, buf_pool); if (UT_LIST_GET_LEN(buf_pool->LRU) > BUF_LRU_OLD_MIN_LEN) { ut_ad(buf_pool->LRU_old); /* Adjust the length of the old block list if necessary */ buf_page_set_old(bpage, old); buf_LRU_old_adjust_len(buf_pool); } else if (UT_LIST_GET_LEN(buf_pool->LRU) == BUF_LRU_OLD_MIN_LEN) { /* The LRU list is now long enough for LRU_old to become defined: init it */ buf_LRU_old_init(buf_pool); } else { buf_page_set_old(bpage, buf_pool->LRU_old != NULL); } /* If this is a zipped block with decompressed frame as well then put it on the unzip_LRU list */ if (buf_page_belongs_to_unzip_LRU(bpage)) { buf_unzip_LRU_add_block((buf_block_t*) bpage, old); } } /******************************************************************//** Adds a block to the LRU list. Please make sure that the page_size is already set when invoking the function, so that we can get correct page_size from the buffer page when adding a block into LRU */ void buf_LRU_add_block( /*==============*/ buf_page_t* bpage, /*!< in: control block */ ibool old) /*!< in: TRUE if should be put to the old blocks in the LRU list, else put to the start; if the LRU list is very short, the block is added to the start, regardless of this parameter */ { buf_LRU_add_block_low(bpage, old); } /******************************************************************//** Moves a block to the start of the LRU list. */ void buf_LRU_make_block_young( /*=====================*/ buf_page_t* bpage) /*!< in: control block */ { buf_pool_t* buf_pool = buf_pool_from_bpage(bpage); ut_ad(buf_pool_mutex_own(buf_pool)); if (bpage->old) { buf_pool->stat.n_pages_made_young++; } buf_LRU_remove_block(bpage); buf_LRU_add_block_low(bpage, FALSE); } /******************************************************************//** Try to free a block. If bpage is a descriptor of a compressed-only page, the descriptor object will be freed as well. NOTE: If this function returns true, it will temporarily release buf_pool->mutex. Furthermore, the page frame will no longer be accessible via bpage. The caller must hold buf_pool->mutex and must not hold any buf_page_get_mutex() when calling this function. @return true if freed, false otherwise. */ bool buf_LRU_free_page( /*===============*/ buf_page_t* bpage, /*!< in: block to be freed */ bool zip) /*!< in: true if should remove also the compressed page of an uncompressed page */ { buf_page_t* b = NULL; buf_pool_t* buf_pool = buf_pool_from_bpage(bpage); rw_lock_t* hash_lock = buf_page_hash_lock_get(buf_pool, bpage->id); BPageMutex* block_mutex = buf_page_get_mutex(bpage); ut_ad(buf_pool_mutex_own(buf_pool)); ut_ad(buf_page_in_file(bpage)); ut_ad(bpage->in_LRU_list); rw_lock_x_lock(hash_lock); mutex_enter(block_mutex); if (!buf_page_can_relocate(bpage)) { /* Do not free buffer fixed and I/O-fixed blocks. */ goto func_exit; } #ifdef UNIV_IBUF_COUNT_DEBUG ut_a(ibuf_count_get(bpage->id) == 0); #endif /* UNIV_IBUF_COUNT_DEBUG */ if (zip || !bpage->zip.data) { /* This would completely free the block. */ /* Do not completely free dirty blocks. */ if (bpage->oldest_modification) { goto func_exit; } } else if (bpage->oldest_modification > 0 && buf_page_get_state(bpage) != BUF_BLOCK_FILE_PAGE) { ut_ad(buf_page_get_state(bpage) == BUF_BLOCK_ZIP_DIRTY); func_exit: rw_lock_x_unlock(hash_lock); mutex_exit(block_mutex); return(false); } else if (buf_page_get_state(bpage) == BUF_BLOCK_FILE_PAGE) { b = buf_page_alloc_descriptor(); ut_a(b); memcpy(b, bpage, sizeof *b); } ut_ad(buf_pool_mutex_own(buf_pool)); ut_ad(buf_page_in_file(bpage)); ut_ad(bpage->in_LRU_list); ut_ad(!bpage->in_flush_list == !bpage->oldest_modification); DBUG_PRINT("ib_buf", ("free page %u:%u", bpage->id.space(), bpage->id.page_no())); ut_ad(rw_lock_own(hash_lock, RW_LOCK_X)); ut_ad(buf_page_can_relocate(bpage)); if (!buf_LRU_block_remove_hashed(bpage, zip)) { return(true); } /* buf_LRU_block_remove_hashed() releases the hash_lock */ ut_ad(!rw_lock_own(hash_lock, RW_LOCK_X) && !rw_lock_own(hash_lock, RW_LOCK_S)); /* We have just freed a BUF_BLOCK_FILE_PAGE. If b != NULL then it was a compressed page with an uncompressed frame and we are interested in freeing only the uncompressed frame. Therefore we have to reinsert the compressed page descriptor into the LRU and page_hash (and possibly flush_list). if b == NULL then it was a regular page that has been freed */ if (b != NULL) { buf_page_t* prev_b = UT_LIST_GET_PREV(LRU, b); rw_lock_x_lock(hash_lock); mutex_enter(block_mutex); ut_a(!buf_page_hash_get_low(buf_pool, b->id)); b->state = b->oldest_modification ? BUF_BLOCK_ZIP_DIRTY : BUF_BLOCK_ZIP_PAGE; ut_ad(b->size.is_compressed()); UNIV_MEM_DESC(b->zip.data, b->size.physical()); /* The fields in_page_hash and in_LRU_list of the to-be-freed block descriptor should have been cleared in buf_LRU_block_remove_hashed(), which invokes buf_LRU_remove_block(). */ ut_ad(!bpage->in_page_hash); ut_ad(!bpage->in_LRU_list); /* bpage->state was BUF_BLOCK_FILE_PAGE because b != NULL. The type cast below is thus valid. */ ut_ad(!((buf_block_t*) bpage)->in_unzip_LRU_list); /* The fields of bpage were copied to b before buf_LRU_block_remove_hashed() was invoked. */ ut_ad(!b->in_zip_hash); ut_ad(b->in_page_hash); ut_ad(b->in_LRU_list); HASH_INSERT(buf_page_t, hash, buf_pool->page_hash, b->id.fold(), b); /* Insert b where bpage was in the LRU list. */ if (prev_b != NULL) { ulint lru_len; ut_ad(prev_b->in_LRU_list); ut_ad(buf_page_in_file(prev_b)); UT_LIST_INSERT_AFTER(buf_pool->LRU, prev_b, b); incr_LRU_size_in_bytes(b, buf_pool); if (buf_page_is_old(b)) { buf_pool->LRU_old_len++; if (buf_pool->LRU_old == UT_LIST_GET_NEXT(LRU, b)) { buf_pool->LRU_old = b; } } lru_len = UT_LIST_GET_LEN(buf_pool->LRU); if (lru_len > BUF_LRU_OLD_MIN_LEN) { ut_ad(buf_pool->LRU_old); /* Adjust the length of the old block list if necessary */ buf_LRU_old_adjust_len(buf_pool); } else if (lru_len == BUF_LRU_OLD_MIN_LEN) { /* The LRU list is now long enough for LRU_old to become defined: init it */ buf_LRU_old_init(buf_pool); } #ifdef UNIV_LRU_DEBUG /* Check that the "old" flag is consistent in the block and its neighbours. */ buf_page_set_old(b, buf_page_is_old(b)); #endif /* UNIV_LRU_DEBUG */ } else { ut_d(b->in_LRU_list = FALSE); buf_LRU_add_block_low(b, buf_page_is_old(b)); } if (b->state == BUF_BLOCK_ZIP_PAGE) { #if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG buf_LRU_insert_zip_clean(b); #endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */ } else { /* Relocate on buf_pool->flush_list. */ buf_flush_relocate_on_flush_list(bpage, b); } bpage->zip.data = NULL; page_zip_set_size(&bpage->zip, 0); bpage->size.copy_from(page_size_t(bpage->size.logical(), bpage->size.logical(), false)); mutex_exit(block_mutex); /* Prevent buf_page_get_gen() from decompressing the block while we release buf_pool->mutex and block_mutex. */ block_mutex = buf_page_get_mutex(b); mutex_enter(block_mutex); buf_page_set_sticky(b); mutex_exit(block_mutex); rw_lock_x_unlock(hash_lock); } buf_pool_mutex_exit(buf_pool); /* Remove possible adaptive hash index on the page. The page was declared uninitialized by buf_LRU_block_remove_hashed(). We need to flag the contents of the page valid (which it still is) in order to avoid bogus Valgrind warnings.*/ UNIV_MEM_VALID(((buf_block_t*) bpage)->frame, UNIV_PAGE_SIZE); btr_search_drop_page_hash_index((buf_block_t*) bpage); UNIV_MEM_INVALID(((buf_block_t*) bpage)->frame, UNIV_PAGE_SIZE); if (b != NULL) { /* Compute and stamp the compressed page checksum while not holding any mutex. The block is already half-freed (BUF_BLOCK_REMOVE_HASH) and removed from buf_pool->page_hash, thus inaccessible by any other thread. */ ut_ad(b->size.is_compressed()); const uint32_t checksum = page_zip_calc_checksum( b->zip.data, b->size.physical(), static_cast( srv_checksum_algorithm)); mach_write_to_4(b->zip.data + FIL_PAGE_SPACE_OR_CHKSUM, checksum); } buf_pool_mutex_enter(buf_pool); if (b != NULL) { mutex_enter(block_mutex); buf_page_unset_sticky(b); mutex_exit(block_mutex); } buf_LRU_block_free_hashed_page((buf_block_t*) bpage); return(true); } /******************************************************************//** Puts a block back to the free list. */ void buf_LRU_block_free_non_file_page( /*=============================*/ buf_block_t* block) /*!< in: block, must not contain a file page */ { void* data; buf_pool_t* buf_pool = buf_pool_from_block(block); ut_ad(buf_pool_mutex_own(buf_pool)); ut_ad(buf_page_mutex_own(block)); switch (buf_block_get_state(block)) { case BUF_BLOCK_MEMORY: case BUF_BLOCK_READY_FOR_USE: break; default: ut_error; } assert_block_ahi_empty(block); ut_ad(!block->page.in_free_list); ut_ad(!block->page.in_flush_list); ut_ad(!block->page.in_LRU_list); buf_block_set_state(block, BUF_BLOCK_NOT_USED); UNIV_MEM_ALLOC(block->frame, UNIV_PAGE_SIZE); #ifdef UNIV_DEBUG /* Wipe contents of page to reveal possible stale pointers to it */ memset(block->frame, '\0', UNIV_PAGE_SIZE); #else /* Wipe page_no and space_id */ memset(block->frame + FIL_PAGE_OFFSET, 0xfe, 4); memset(block->frame + FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID, 0xfe, 4); #endif /* UNIV_DEBUG */ data = block->page.zip.data; if (data != NULL) { block->page.zip.data = NULL; buf_page_mutex_exit(block); buf_pool_mutex_exit_forbid(buf_pool); ut_ad(block->page.size.is_compressed()); buf_buddy_free(buf_pool, data, block->page.size.physical()); buf_pool_mutex_exit_allow(buf_pool); buf_page_mutex_enter(block); page_zip_set_size(&block->page.zip, 0); block->page.size.copy_from( page_size_t(block->page.size.logical(), block->page.size.logical(), false)); } if (buf_pool->curr_size < buf_pool->old_size && UT_LIST_GET_LEN(buf_pool->withdraw) < buf_pool->withdraw_target && buf_block_will_withdrawn(buf_pool, block)) { /* This should be withdrawn */ UT_LIST_ADD_LAST( buf_pool->withdraw, &block->page); ut_d(block->in_withdraw_list = TRUE); } else { UT_LIST_ADD_FIRST(buf_pool->free, &block->page); ut_d(block->page.in_free_list = TRUE); } UNIV_MEM_ASSERT_AND_FREE(block->frame, UNIV_PAGE_SIZE); } /******************************************************************//** Takes a block out of the LRU list and page hash table. If the block is compressed-only (BUF_BLOCK_ZIP_PAGE), the object will be freed. The caller must hold buf_pool->mutex, the buf_page_get_mutex() mutex and the appropriate hash_lock. This function will release the buf_page_get_mutex() and the hash_lock. If a compressed page is freed other compressed pages may be relocated. @retval true if BUF_BLOCK_FILE_PAGE was removed from page_hash. The caller needs to free the page to the free list @retval false if BUF_BLOCK_ZIP_PAGE was removed from page_hash. In this case the block is already returned to the buddy allocator. */ static bool buf_LRU_block_remove_hashed( /*========================*/ buf_page_t* bpage, /*!< in: block, must contain a file page and be in a state where it can be freed; there may or may not be a hash index to the page */ bool zip) /*!< in: true if should remove also the compressed page of an uncompressed page */ { const buf_page_t* hashed_bpage; buf_pool_t* buf_pool = buf_pool_from_bpage(bpage); rw_lock_t* hash_lock; ut_ad(buf_pool_mutex_own(buf_pool)); ut_ad(mutex_own(buf_page_get_mutex(bpage))); hash_lock = buf_page_hash_lock_get(buf_pool, bpage->id); ut_ad(rw_lock_own(hash_lock, RW_LOCK_X)); ut_a(buf_page_get_io_fix(bpage) == BUF_IO_NONE); ut_a(bpage->buf_fix_count == 0); buf_LRU_remove_block(bpage); buf_pool->freed_page_clock += 1; switch (buf_page_get_state(bpage)) { case BUF_BLOCK_FILE_PAGE: UNIV_MEM_ASSERT_W(bpage, sizeof(buf_block_t)); UNIV_MEM_ASSERT_W(((buf_block_t*) bpage)->frame, UNIV_PAGE_SIZE); buf_block_modify_clock_inc((buf_block_t*) bpage); if (bpage->zip.data) { const page_t* page = ((buf_block_t*) bpage)->frame; ut_a(!zip || bpage->oldest_modification == 0); ut_ad(bpage->size.is_compressed()); switch (fil_page_get_type(page)) { case FIL_PAGE_TYPE_ALLOCATED: case FIL_PAGE_INODE: case FIL_PAGE_IBUF_BITMAP: case FIL_PAGE_TYPE_FSP_HDR: case FIL_PAGE_TYPE_XDES: /* These are essentially uncompressed pages. */ if (!zip) { /* InnoDB writes the data to the uncompressed page frame. Copy it to the compressed page, which will be preserved. */ memcpy(bpage->zip.data, page, bpage->size.physical()); } break; case FIL_PAGE_TYPE_ZBLOB: case FIL_PAGE_TYPE_ZBLOB2: break; case FIL_PAGE_INDEX: case FIL_PAGE_RTREE: #ifdef UNIV_ZIP_DEBUG ut_a(page_zip_validate( &bpage->zip, page, ((buf_block_t*) bpage)->index)); #endif /* UNIV_ZIP_DEBUG */ break; default: ib::error() << "The compressed page to be" " evicted seems corrupt:"; ut_print_buf(stderr, page, bpage->size.logical()); ib::error() << "Possibly older version of" " the page:"; ut_print_buf(stderr, bpage->zip.data, bpage->size.physical()); putc('\n', stderr); ut_error; } break; } /* fall through */ case BUF_BLOCK_ZIP_PAGE: ut_a(bpage->oldest_modification == 0); if (bpage->size.is_compressed()) { UNIV_MEM_ASSERT_W(bpage->zip.data, bpage->size.physical()); } break; case BUF_BLOCK_POOL_WATCH: case BUF_BLOCK_ZIP_DIRTY: case BUF_BLOCK_NOT_USED: case BUF_BLOCK_READY_FOR_USE: case BUF_BLOCK_MEMORY: case BUF_BLOCK_REMOVE_HASH: ut_error; break; } hashed_bpage = buf_page_hash_get_low(buf_pool, bpage->id); if (bpage != hashed_bpage) { ib::error() << "Page " << bpage->id << " not found in the hash table"; #ifdef UNIV_DEBUG ib::error() << "in_page_hash:" << bpage->in_page_hash << " in_zip_hash:" << bpage->in_zip_hash // << " in_free_list:"<< bpage->in_fee_list << " in_flush_list:" << bpage->in_flush_list << " in_LRU_list:" << bpage->in_LRU_list << " zip.data:" << bpage->zip.data << " zip_size:" << bpage->size.logical() << " page_state:" << buf_page_get_state(bpage); #else ib::error() << " zip.data:" << bpage->zip.data << " zip_size:" << bpage->size.logical() << " page_state:" << buf_page_get_state(bpage); #endif if (hashed_bpage) { ib::error() << "In hash table we find block " << hashed_bpage << " of " << hashed_bpage->id << " which is not " << bpage; } #if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG mutex_exit(buf_page_get_mutex(bpage)); rw_lock_x_unlock(hash_lock); buf_pool_mutex_exit(buf_pool); buf_print(); buf_LRU_print(); buf_validate(); buf_LRU_validate(); #endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */ ut_error; } ut_ad(!bpage->in_zip_hash); ut_ad(bpage->in_page_hash); ut_d(bpage->in_page_hash = FALSE); HASH_DELETE(buf_page_t, hash, buf_pool->page_hash, bpage->id.fold(), bpage); switch (buf_page_get_state(bpage)) { case BUF_BLOCK_ZIP_PAGE: ut_ad(!bpage->in_free_list); ut_ad(!bpage->in_flush_list); ut_ad(!bpage->in_LRU_list); ut_a(bpage->zip.data); ut_a(bpage->size.is_compressed()); #if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG UT_LIST_REMOVE(buf_pool->zip_clean, bpage); #endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */ mutex_exit(&buf_pool->zip_mutex); rw_lock_x_unlock(hash_lock); buf_pool_mutex_exit_forbid(buf_pool); buf_buddy_free(buf_pool, bpage->zip.data, bpage->size.physical()); buf_pool_mutex_exit_allow(buf_pool); buf_page_free_descriptor(bpage); return(false); case BUF_BLOCK_FILE_PAGE: memset(((buf_block_t*) bpage)->frame + FIL_PAGE_OFFSET, 0xff, 4); memset(((buf_block_t*) bpage)->frame + FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID, 0xff, 4); UNIV_MEM_INVALID(((buf_block_t*) bpage)->frame, UNIV_PAGE_SIZE); buf_page_set_state(bpage, BUF_BLOCK_REMOVE_HASH); /* Question: If we release bpage and hash mutex here then what protects us against: 1) Some other thread buffer fixing this page 2) Some other thread trying to read this page and not finding it in buffer pool attempting to read it from the disk. Answer: 1) Cannot happen because the page is no longer in the page_hash. Only possibility is when while invalidating a tablespace we buffer fix the prev_page in LRU to avoid relocation during the scan. But that is not possible because we are holding buf_pool mutex. 2) Not possible because in buf_page_init_for_read() we do a look up of page_hash while holding buf_pool mutex and since we are holding buf_pool mutex here and by the time we'll release it in the caller we'd have inserted the compressed only descriptor in the page_hash. */ rw_lock_x_unlock(hash_lock); mutex_exit(&((buf_block_t*) bpage)->mutex); if (zip && bpage->zip.data) { /* Free the compressed page. */ void* data = bpage->zip.data; bpage->zip.data = NULL; ut_ad(!bpage->in_free_list); ut_ad(!bpage->in_flush_list); ut_ad(!bpage->in_LRU_list); buf_pool_mutex_exit_forbid(buf_pool); buf_buddy_free(buf_pool, data, bpage->size.physical()); buf_pool_mutex_exit_allow(buf_pool); page_zip_set_size(&bpage->zip, 0); bpage->size.copy_from( page_size_t(bpage->size.logical(), bpage->size.logical(), false)); } return(true); case BUF_BLOCK_POOL_WATCH: case BUF_BLOCK_ZIP_DIRTY: case BUF_BLOCK_NOT_USED: case BUF_BLOCK_READY_FOR_USE: case BUF_BLOCK_MEMORY: case BUF_BLOCK_REMOVE_HASH: break; } ut_error; return(false); } /******************************************************************//** Puts a file page whose has no hash index to the free list. */ static void buf_LRU_block_free_hashed_page( /*===========================*/ buf_block_t* block) /*!< in: block, must contain a file page and be in a state where it can be freed */ { buf_pool_t* buf_pool = buf_pool_from_block(block); ut_ad(buf_pool_mutex_own(buf_pool)); buf_page_mutex_enter(block); if (buf_pool->flush_rbt == NULL) { block->page.id.reset(ULINT32_UNDEFINED, ULINT32_UNDEFINED); } buf_block_set_state(block, BUF_BLOCK_MEMORY); buf_LRU_block_free_non_file_page(block); buf_page_mutex_exit(block); } /******************************************************************//** Remove one page from LRU list and put it to free list */ void buf_LRU_free_one_page( /*==================*/ buf_page_t* bpage) /*!< in/out: block, must contain a file page and be in a state where it can be freed; there may or may not be a hash index to the page */ { buf_pool_t* buf_pool = buf_pool_from_bpage(bpage); rw_lock_t* hash_lock = buf_page_hash_lock_get(buf_pool, bpage->id); BPageMutex* block_mutex = buf_page_get_mutex(bpage); ut_ad(buf_pool_mutex_own(buf_pool)); rw_lock_x_lock(hash_lock); mutex_enter(block_mutex); if (buf_LRU_block_remove_hashed(bpage, true)) { buf_LRU_block_free_hashed_page((buf_block_t*) bpage); } /* buf_LRU_block_remove_hashed() releases hash_lock and block_mutex */ ut_ad(!rw_lock_own(hash_lock, RW_LOCK_X) && !rw_lock_own(hash_lock, RW_LOCK_S)); ut_ad(!mutex_own(block_mutex)); } /**********************************************************************//** Updates buf_pool->LRU_old_ratio for one buffer pool instance. @return updated old_pct */ static uint buf_LRU_old_ratio_update_instance( /*==============================*/ buf_pool_t* buf_pool,/*!< in: buffer pool instance */ uint old_pct,/*!< in: Reserve this percentage of the buffer pool for "old" blocks. */ ibool adjust) /*!< in: TRUE=adjust the LRU list; FALSE=just assign buf_pool->LRU_old_ratio during the initialization of InnoDB */ { uint ratio; ratio = old_pct * BUF_LRU_OLD_RATIO_DIV / 100; if (ratio < BUF_LRU_OLD_RATIO_MIN) { ratio = BUF_LRU_OLD_RATIO_MIN; } else if (ratio > BUF_LRU_OLD_RATIO_MAX) { ratio = BUF_LRU_OLD_RATIO_MAX; } if (adjust) { buf_pool_mutex_enter(buf_pool); if (ratio != buf_pool->LRU_old_ratio) { buf_pool->LRU_old_ratio = ratio; if (UT_LIST_GET_LEN(buf_pool->LRU) >= BUF_LRU_OLD_MIN_LEN) { buf_LRU_old_adjust_len(buf_pool); } } buf_pool_mutex_exit(buf_pool); } else { buf_pool->LRU_old_ratio = ratio; } /* the reverse of ratio = old_pct * BUF_LRU_OLD_RATIO_DIV / 100 */ return((uint) (ratio * 100 / (double) BUF_LRU_OLD_RATIO_DIV + 0.5)); } /**********************************************************************//** Updates buf_pool->LRU_old_ratio. @return updated old_pct */ uint buf_LRU_old_ratio_update( /*=====================*/ uint old_pct,/*!< in: Reserve this percentage of the buffer pool for "old" blocks. */ ibool adjust) /*!< in: TRUE=adjust the LRU list; FALSE=just assign buf_pool->LRU_old_ratio during the initialization of InnoDB */ { uint new_ratio = 0; for (ulint i = 0; i < srv_buf_pool_instances; i++) { buf_pool_t* buf_pool; buf_pool = buf_pool_from_array(i); new_ratio = buf_LRU_old_ratio_update_instance( buf_pool, old_pct, adjust); } return(new_ratio); } /********************************************************************//** Update the historical stats that we are collecting for LRU eviction policy at the end of each interval. */ void buf_LRU_stat_update(void) /*=====================*/ { buf_LRU_stat_t* item; buf_pool_t* buf_pool; bool evict_started = FALSE; buf_LRU_stat_t cur_stat; /* If we haven't started eviction yet then don't update stats. */ for (ulint i = 0; i < srv_buf_pool_instances; i++) { buf_pool = buf_pool_from_array(i); if (buf_pool->freed_page_clock != 0) { evict_started = true; break; } } if (!evict_started) { goto func_exit; } /* Update the index. */ item = &buf_LRU_stat_arr[buf_LRU_stat_arr_ind]; buf_LRU_stat_arr_ind++; buf_LRU_stat_arr_ind %= BUF_LRU_STAT_N_INTERVAL; /* Add the current value and subtract the obsolete entry. Since buf_LRU_stat_cur is not protected by any mutex, it can be changing between adding to buf_LRU_stat_sum and copying to item. Assign it to local variables to make sure the same value assign to the buf_LRU_stat_sum and item */ cur_stat = buf_LRU_stat_cur; buf_LRU_stat_sum.io += cur_stat.io - item->io; buf_LRU_stat_sum.unzip += cur_stat.unzip - item->unzip; /* Put current entry in the array. */ memcpy(item, &cur_stat, sizeof *item); func_exit: /* Clear the current entry. */ memset(&buf_LRU_stat_cur, 0, sizeof buf_LRU_stat_cur); } #if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG /**********************************************************************//** Validates the LRU list for one buffer pool instance. */ static void buf_LRU_validate_instance( /*======================*/ buf_pool_t* buf_pool) { ulint old_len; ulint new_len; buf_pool_mutex_enter(buf_pool); if (UT_LIST_GET_LEN(buf_pool->LRU) >= BUF_LRU_OLD_MIN_LEN) { ut_a(buf_pool->LRU_old); old_len = buf_pool->LRU_old_len; new_len = ut_min(UT_LIST_GET_LEN(buf_pool->LRU) * buf_pool->LRU_old_ratio / BUF_LRU_OLD_RATIO_DIV, UT_LIST_GET_LEN(buf_pool->LRU) - (BUF_LRU_OLD_TOLERANCE + BUF_LRU_NON_OLD_MIN_LEN)); ut_a(old_len >= new_len - BUF_LRU_OLD_TOLERANCE); ut_a(old_len <= new_len + BUF_LRU_OLD_TOLERANCE); } CheckInLRUList::validate(buf_pool); old_len = 0; for (buf_page_t* bpage = UT_LIST_GET_FIRST(buf_pool->LRU); bpage != NULL; bpage = UT_LIST_GET_NEXT(LRU, bpage)) { switch (buf_page_get_state(bpage)) { case BUF_BLOCK_POOL_WATCH: case BUF_BLOCK_NOT_USED: case BUF_BLOCK_READY_FOR_USE: case BUF_BLOCK_MEMORY: case BUF_BLOCK_REMOVE_HASH: ut_error; break; case BUF_BLOCK_FILE_PAGE: ut_ad(((buf_block_t*) bpage)->in_unzip_LRU_list == buf_page_belongs_to_unzip_LRU(bpage)); case BUF_BLOCK_ZIP_PAGE: case BUF_BLOCK_ZIP_DIRTY: break; } if (buf_page_is_old(bpage)) { const buf_page_t* prev = UT_LIST_GET_PREV(LRU, bpage); const buf_page_t* next = UT_LIST_GET_NEXT(LRU, bpage); if (!old_len++) { ut_a(buf_pool->LRU_old == bpage); } else { ut_a(!prev || buf_page_is_old(prev)); } ut_a(!next || buf_page_is_old(next)); } } ut_a(buf_pool->LRU_old_len == old_len); CheckInFreeList::validate(buf_pool); for (buf_page_t* bpage = UT_LIST_GET_FIRST(buf_pool->free); bpage != NULL; bpage = UT_LIST_GET_NEXT(list, bpage)) { ut_a(buf_page_get_state(bpage) == BUF_BLOCK_NOT_USED); } CheckUnzipLRUAndLRUList::validate(buf_pool); for (buf_block_t* block = UT_LIST_GET_FIRST(buf_pool->unzip_LRU); block != NULL; block = UT_LIST_GET_NEXT(unzip_LRU, block)) { ut_ad(block->in_unzip_LRU_list); ut_ad(block->page.in_LRU_list); ut_a(buf_page_belongs_to_unzip_LRU(&block->page)); } buf_pool_mutex_exit(buf_pool); } /**********************************************************************//** Validates the LRU list. @return TRUE */ ibool buf_LRU_validate(void) /*==================*/ { for (ulint i = 0; i < srv_buf_pool_instances; i++) { buf_pool_t* buf_pool; buf_pool = buf_pool_from_array(i); buf_LRU_validate_instance(buf_pool); } return(TRUE); } #endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */ #if defined UNIV_DEBUG_PRINT || defined UNIV_DEBUG || defined UNIV_BUF_DEBUG /**********************************************************************//** Prints the LRU list for one buffer pool instance. */ static void buf_LRU_print_instance( /*===================*/ buf_pool_t* buf_pool) { buf_pool_mutex_enter(buf_pool); for (const buf_page_t* bpage = UT_LIST_GET_FIRST(buf_pool->LRU); bpage != NULL; bpage = UT_LIST_GET_NEXT(LRU, bpage)) { mutex_enter(buf_page_get_mutex(bpage)); fprintf(stderr, "BLOCK space %u page %u ", bpage->id.space(), bpage->id.page_no()); if (buf_page_is_old(bpage)) { fputs("old ", stderr); } if (bpage->buf_fix_count) { fprintf(stderr, "buffix count %u ", bpage->buf_fix_count); } if (buf_page_get_io_fix(bpage)) { fprintf(stderr, "io_fix %d ", buf_page_get_io_fix(bpage)); } if (bpage->oldest_modification) { fputs("modif. ", stderr); } switch (buf_page_get_state(bpage)) { const byte* frame; case BUF_BLOCK_FILE_PAGE: frame = buf_block_get_frame((buf_block_t*) bpage); fprintf(stderr, "\ntype " ULINTPF " index id " IB_ID_FMT "\n", fil_page_get_type(frame), btr_page_get_index_id(frame)); break; case BUF_BLOCK_ZIP_PAGE: frame = bpage->zip.data; fprintf(stderr, "\ntype " ULINTPF " size " ULINTPF " index id " IB_ID_FMT "\n", fil_page_get_type(frame), bpage->size.physical(), btr_page_get_index_id(frame)); break; default: fprintf(stderr, "\n!state %d!\n", buf_page_get_state(bpage)); break; } mutex_exit(buf_page_get_mutex(bpage)); } buf_pool_mutex_exit(buf_pool); } /**********************************************************************//** Prints the LRU list. */ void buf_LRU_print(void) /*===============*/ { for (ulint i = 0; i < srv_buf_pool_instances; i++) { buf_pool_t* buf_pool; buf_pool = buf_pool_from_array(i); buf_LRU_print_instance(buf_pool); } } #endif /* UNIV_DEBUG_PRINT || UNIV_DEBUG || UNIV_BUF_DEBUG */