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Diffstat (limited to 'storage/innobase/include/page0zip.inl')
| -rw-r--r-- | storage/innobase/include/page0zip.inl | 317 |
1 files changed, 317 insertions, 0 deletions
diff --git a/storage/innobase/include/page0zip.inl b/storage/innobase/include/page0zip.inl new file mode 100644 index 00000000..afc877c3 --- /dev/null +++ b/storage/innobase/include/page0zip.inl @@ -0,0 +1,317 @@ +/***************************************************************************** + +Copyright (c) 2005, 2016, Oracle and/or its affiliates. All Rights Reserved. +Copyright (c) 2017, 2022, 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, Fifth Floor, Boston, MA 02110-1335 USA + +*****************************************************************************/ + +/**************************************************//** +@file include/page0zip.ic +Compressed page interface + +Created June 2005 by Marko Makela +*******************************************************/ + +#include "page0page.h" + +/* The format of compressed pages is as follows. + +The header and trailer of the uncompressed pages, excluding the page +directory in the trailer, are copied as is to the header and trailer +of the compressed page. + +At the end of the compressed page, there is a dense page directory +pointing to every user record contained on the page, including deleted +records on the free list. The dense directory is indexed in the +collation order, i.e., in the order in which the record list is +linked on the uncompressed page. The infimum and supremum records are +excluded. The two most significant bits of the entries are allocated +for the delete-mark and an n_owned flag indicating the last record in +a chain of records pointed to from the sparse page directory on the +uncompressed page. + +The data between PAGE_ZIP_START and the last page directory entry will +be written in compressed format, starting at offset PAGE_DATA. +Infimum and supremum records are not stored. We exclude the +REC_N_NEW_EXTRA_BYTES in every record header. These can be recovered +from the dense page directory stored at the end of the compressed +page. + +The fields node_ptr (in non-leaf B-tree nodes; level>0), trx_id and +roll_ptr (in leaf B-tree nodes; level=0), and BLOB pointers of +externally stored columns are stored separately, in ascending order of +heap_no and column index, starting backwards from the dense page +directory. + +The compressed data stream may be followed by a modification log +covering the compressed portion of the page, as follows. + +MODIFICATION LOG ENTRY FORMAT +- write record: + - (heap_no - 1) << 1 (1..2 bytes) + - extra bytes backwards + - data bytes +- clear record: + - (heap_no - 1) << 1 | 1 (1..2 bytes) + +The integer values are stored in a variable-length format: +- 0xxxxxxx: 0..127 +- 1xxxxxxx xxxxxxxx: 0..32767 + +The end of the modification log is marked by a 0 byte. + +In summary, the compressed page looks like this: + +(1) Uncompressed page header (PAGE_DATA bytes) +(2) Compressed index information +(3) Compressed page data +(4) Page modification log (page_zip->m_start..page_zip->m_end) +(5) Empty zero-filled space +(6) BLOB pointers (on leaf pages) + - BTR_EXTERN_FIELD_REF_SIZE for each externally stored column + - in descending collation order +(7) Uncompressed columns of user records, n_dense * uncompressed_size bytes, + - indexed by heap_no + - DATA_TRX_ID_LEN + DATA_ROLL_PTR_LEN for leaf pages of clustered indexes + - REC_NODE_PTR_SIZE for non-leaf pages + - 0 otherwise +(8) dense page directory, stored backwards + - n_dense = n_heap - 2 + - existing records in ascending collation order + - deleted records (free list) in link order +*/ + +/**********************************************************************//** +Determine the size of a compressed page in bytes. +@return size in bytes */ +UNIV_INLINE +ulint +page_zip_get_size( +/*==============*/ + const page_zip_des_t* page_zip) /*!< in: compressed page */ +{ + ulint size; + + if (!page_zip->ssize) { + return(0); + } + + size = (UNIV_ZIP_SIZE_MIN >> 1) << page_zip->ssize; + + ut_ad(size >= UNIV_ZIP_SIZE_MIN); + ut_ad(size <= srv_page_size); + + return(size); +} +/**********************************************************************//** +Set the size of a compressed page in bytes. */ +UNIV_INLINE +void +page_zip_set_size( +/*==============*/ + page_zip_des_t* page_zip, /*!< in/out: compressed page */ + ulint size) /*!< in: size in bytes */ +{ + if (size) { + unsigned ssize; + + ut_ad(ut_is_2pow(size)); + + for (ssize = 1; size > (512U << ssize); ssize++) { + } + + page_zip->ssize = ssize & ((1U << PAGE_ZIP_SSIZE_BITS) - 1); + } else { + page_zip->ssize = 0; + } + + ut_ad(page_zip_get_size(page_zip) == size); +} + +/** Determine if a record is so big that it needs to be stored externally. +@param[in] rec_size length of the record in bytes +@param[in] comp nonzero=compact format +@param[in] n_fields number of fields in the record; ignored if +tablespace is not compressed +@param[in] zip_size ROW_FORMAT=COMPRESSED page size, or 0 +@return false if the entire record can be stored locally on the page */ +inline bool page_zip_rec_needs_ext(ulint rec_size, ulint comp, ulint n_fields, + ulint zip_size) +{ + /* FIXME: row size check is this function seems to be the most correct. + Put it in a separate function and use in more places of InnoDB */ + + ut_ad(rec_size + > ulint(comp ? REC_N_NEW_EXTRA_BYTES : REC_N_OLD_EXTRA_BYTES)); + ut_ad(comp || !zip_size); + +#if UNIV_PAGE_SIZE_MAX > COMPRESSED_REC_MAX_DATA_SIZE + if (comp ? rec_size >= COMPRESSED_REC_MAX_DATA_SIZE : + rec_size >= REDUNDANT_REC_MAX_DATA_SIZE) { + return(TRUE); + } +#endif + + if (zip_size) { + ut_ad(comp); + /* On a compressed page, there is a two-byte entry in + the dense page directory for every record. But there + is no record header. There should be enough room for + one record on an empty leaf page. Subtract 1 byte for + the encoded heap number. Check also the available space + on the uncompressed page. */ + return(rec_size - (REC_N_NEW_EXTRA_BYTES - 2 - 1) + >= page_zip_empty_size(n_fields, zip_size) + || rec_size >= page_get_free_space_of_empty(TRUE) / 2); + } + + return(rec_size >= page_get_free_space_of_empty(comp) / 2); +} + +#ifdef UNIV_DEBUG +/**********************************************************************//** +Validate a compressed page descriptor. +@return TRUE if ok */ +UNIV_INLINE +ibool +page_zip_simple_validate( +/*=====================*/ + const page_zip_des_t* page_zip)/*!< in: compressed page descriptor */ +{ + ut_ad(page_zip); + ut_ad(page_zip->data); + ut_ad(page_zip->ssize <= PAGE_ZIP_SSIZE_MAX); + ut_ad(page_zip_get_size(page_zip) + > PAGE_DATA + PAGE_ZIP_DIR_SLOT_SIZE); + ut_ad(page_zip->m_start <= page_zip->m_end); + ut_ad(page_zip->m_end < page_zip_get_size(page_zip)); + ut_ad(page_zip->n_blobs + < page_zip_get_size(page_zip) / BTR_EXTERN_FIELD_REF_SIZE); + return(TRUE); +} +#endif /* UNIV_DEBUG */ + +/**********************************************************************//** +Determine if the length of the page trailer. +@return length of the page trailer, in bytes, not including the +terminating zero byte of the modification log */ +UNIV_INLINE +ibool +page_zip_get_trailer_len( +/*=====================*/ + const page_zip_des_t* page_zip,/*!< in: compressed page */ + ibool is_clust)/*!< in: TRUE if clustered index */ +{ + ulint uncompressed_size; + + ut_ad(page_zip_simple_validate(page_zip)); + MEM_CHECK_DEFINED(page_zip->data, page_zip_get_size(page_zip)); + + if (!page_is_leaf(page_zip->data)) { + uncompressed_size = PAGE_ZIP_DIR_SLOT_SIZE + + REC_NODE_PTR_SIZE; + ut_ad(!page_zip->n_blobs); + } else if (is_clust) { + uncompressed_size = PAGE_ZIP_DIR_SLOT_SIZE + + DATA_TRX_ID_LEN + DATA_ROLL_PTR_LEN; + } else { + uncompressed_size = PAGE_ZIP_DIR_SLOT_SIZE; + ut_ad(!page_zip->n_blobs); + } + + return (ulint(page_dir_get_n_heap(page_zip->data)) - 2) + * uncompressed_size + + ulint(page_zip->n_blobs) * BTR_EXTERN_FIELD_REF_SIZE; +} + +/**********************************************************************//** +Determine how big record can be inserted without recompressing the page. +@return a positive number indicating the maximum size of a record +whose insertion is guaranteed to succeed, or zero or negative */ +UNIV_INLINE +lint +page_zip_max_ins_size( +/*==================*/ + const page_zip_des_t* page_zip,/*!< in: compressed page */ + ibool is_clust)/*!< in: TRUE if clustered index */ +{ + ulint trailer_len; + + trailer_len = page_zip_get_trailer_len(page_zip, is_clust); + + /* When a record is created, a pointer may be added to + the dense directory. + Likewise, space for the columns that will not be + compressed will be allocated from the page trailer. + Also the BLOB pointers will be allocated from there, but + we may as well count them in the length of the record. */ + + trailer_len += PAGE_ZIP_DIR_SLOT_SIZE; + + return(lint(page_zip_get_size(page_zip) + - trailer_len - page_zip->m_end + - (REC_N_NEW_EXTRA_BYTES - 2))); +} + +/**********************************************************************//** +Determine if enough space is available in the modification log. +@return TRUE if enough space is available */ +UNIV_INLINE +ibool +page_zip_available( +/*===============*/ + const page_zip_des_t* page_zip,/*!< in: compressed page */ + ibool is_clust,/*!< in: TRUE if clustered index */ + ulint length, /*!< in: combined size of the record */ + ulint create) /*!< in: nonzero=add the record to + the heap */ +{ + ulint trailer_len; + + ut_ad(length > REC_N_NEW_EXTRA_BYTES); + + trailer_len = page_zip_get_trailer_len(page_zip, is_clust); + + /* Subtract the fixed extra bytes and add the maximum + space needed for identifying the record (encoded heap_no). */ + length -= REC_N_NEW_EXTRA_BYTES - 2; + + if (create > 0) { + /* When a record is created, a pointer may be added to + the dense directory. + Likewise, space for the columns that will not be + compressed will be allocated from the page trailer. + Also the BLOB pointers will be allocated from there, but + we may as well count them in the length of the record. */ + + trailer_len += PAGE_ZIP_DIR_SLOT_SIZE; + } + + return(length + trailer_len + page_zip->m_end + < page_zip_get_size(page_zip)); +} + +/**********************************************************************//** +Reset the counters used for filling +INFORMATION_SCHEMA.innodb_cmp_per_index. */ +UNIV_INLINE +void +page_zip_reset_stat_per_index() +/*===========================*/ +{ + mysql_mutex_lock(&page_zip_stat_per_index_mutex); + page_zip_stat_per_index.clear(); + mysql_mutex_unlock(&page_zip_stat_per_index_mutex); +} |