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Diffstat (limited to '')
| -rw-r--r-- | storage/innobase/row/row0ext.cc | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/storage/innobase/row/row0ext.cc b/storage/innobase/row/row0ext.cc new file mode 100644 index 00000000..b7a62760 --- /dev/null +++ b/storage/innobase/row/row0ext.cc @@ -0,0 +1,132 @@ +/***************************************************************************** + +Copyright (c) 2006, 2016, Oracle and/or its affiliates. All Rights Reserved. +Copyright (c) 2019, 2020, 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 row/row0ext.cc +Caching of externally stored column prefixes + +Created September 2006 Marko Makela +*******************************************************/ + +#include "row0ext.h" +#include "btr0cur.h" + +/** Fills the column prefix cache of an externally stored column. +@param[in,out] ext column prefix cache +@param[in] i index of ext->ext[] +@param[in] space tablespace +@param[in] dfield data field */ +static +void +row_ext_cache_fill( + row_ext_t* ext, + ulint i, + fil_space_t* space, + const dfield_t* dfield) +{ + const byte* field = static_cast<const byte*>( + dfield_get_data(dfield)); + ulint f_len = dfield_get_len(dfield); + byte* buf = ext->buf + i * ext->max_len; + + ut_ad(ext->max_len > 0); + ut_ad(i < ext->n_ext); + ut_ad(dfield_is_ext(dfield)); + ut_a(f_len >= BTR_EXTERN_FIELD_REF_SIZE); + + if (UNIV_UNLIKELY(!memcmp(field_ref_zero, + field + f_len - BTR_EXTERN_FIELD_REF_SIZE, + BTR_EXTERN_FIELD_REF_SIZE))) { + /* The BLOB pointer is not set: we cannot fetch it */ + ext->len[i] = 0; + } else { + if (ext->max_len == REC_VERSION_56_MAX_INDEX_COL_LEN + && f_len > BTR_EXTERN_FIELD_REF_SIZE) { + /* In this case, the field is in B format or beyond, + (refer to the definition of row_ext_t.max_len) + and the field is already fill with prefix, otherwise + f_len would be BTR_EXTERN_FIELD_REF_SIZE. + So there is no need to re-read the prefix externally, + but just copy the local prefix to buf. Please note + if the ext->len[i] is zero, it means an error + as above. */ + memcpy(buf, field, f_len - BTR_EXTERN_FIELD_REF_SIZE); + ext->len[i] = f_len - BTR_EXTERN_FIELD_REF_SIZE; + } else { + /* Fetch at most ext->max_len of the column. + The column should be non-empty. However, + trx_rollback_all_recovered() may try to + access a half-deleted BLOB if the server previously + crashed during the execution of + btr_free_externally_stored_field(). */ + ext->len[i] = btr_copy_externally_stored_field_prefix( + buf, ext->max_len, ext->zip_size, + field, f_len); + } + } +} + +/********************************************************************//** +Creates a cache of column prefixes of externally stored columns. +@return own: column prefix cache */ +row_ext_t* +row_ext_create( +/*===========*/ + ulint n_ext, /*!< in: number of externally stored columns */ + const ulint* ext, /*!< in: col_no's of externally stored columns + in the InnoDB table object, as reported by + dict_col_get_no(); NOT relative to the records + in the clustered index */ + const dict_table_t& table, /*!< in: table */ + const dtuple_t* tuple, /*!< in: data tuple containing the field + references of the externally stored + columns; must be indexed by col_no; + the clustered index record must be + covered by a lock or a page latch + to prevent deletion (rollback or purge). */ + mem_heap_t* heap) /*!< in: heap where created */ +{ + if (!table.space) { + return NULL; + } + + ut_ad(n_ext > 0); + + row_ext_t* ret = static_cast<row_ext_t*>( + mem_heap_alloc(heap, + (sizeof *ret) + (n_ext - 1) * sizeof ret->len)); + + ret->n_ext = n_ext; + ret->ext = ext; + ret->max_len = DICT_MAX_FIELD_LEN_BY_FORMAT_FLAG(table.flags); + ret->zip_size = dict_tf_get_zip_size(table.flags); + + ret->buf = static_cast<byte*>( + mem_heap_alloc(heap, n_ext * ret->max_len)); + + /* Fetch the BLOB prefixes */ + for (ulint i = 0; i < n_ext; i++) { + const dfield_t* dfield; + + dfield = dtuple_get_nth_field(tuple, ext[i]); + row_ext_cache_fill(ret, i, table.space, dfield); + } + + return(ret); +} |