Eugene Kosov f0aa073f2b MDEV-20950 Reduce size of record offsets ... offset_t: this is a type which represents one record offset. It's unsigned short int. a lot of functions: replace ulint with offset_t btr_pcur_restore_position_func(), page_validate(), row_ins_scan_sec_index_for_duplicate(), row_upd_clust_rec_by_insert_inherit_func(), row_vers_impl_x_locked_low(), trx_undo_prev_version_build(): allocate record offsets on the stack instead of waiting for rec_get_offsets() to allocate it from mem_heap_t. So, reducing memory allocations. RECORD_OFFSET, INDEX_OFFSET: now it's less convenient to store pointers in offset_t* array. One pointer occupies now several offset_t. And those constant are start indexes into array to places where to store pointer values REC_OFFS_HEADER_SIZE: adjusted for the new reality REC_OFFS_NORMAL_SIZE: increase size from 100 to 300 which means less heap allocations. And sizeof(offset_t[REC_OFFS_NORMAL_SIZE]) now is 600 bytes which is smaller than previous 800 bytes. REC_OFFS_SEC_INDEX_SIZE: adjusted for the new reality rem0rec.h, rem0rec.ic, rem0rec.cc: various arguments, return values and local variables types were changed to fix numerous integer conversions issues. enum field_type_t: offset types concept was introduces which replaces old offset flags stuff. Like in earlier version, 2 upper bits are used to store offset type. And this enum represents those types. REC_OFFS_SQL_NULL, REC_OFFS_MASK: removed get_type(), set_type(), get_value(), combine(): these are convenience functions to work with offsets and it's types rec_offs_base()[0]: still uses an old scheme with flags REC_OFFS_COMPACT and REC_OFFS_EXTERNAL rec_offs_base()[i]: these have type offset_t now. Two upper bits contains type.		2019-12-13 00:26:50 +07:00
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ibuf0ibuf.cc	MDEV-20950 Reduce size of record offsets	2019-12-13 00:26:50 +07:00