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Heap tables are allocated blocks to store rows according to my_default_record_cache (mapped to the server global variable read_buffer_size). This causes performance issues when the record length is big (> 1000 bytes) and the my_default_record_cache is small. Changed to instead split the default heap allocation to 1/16 of the allowed space and not use my_default_record_cache anymore when creating the heap. The allocation is also aligned to be just under a power of 2. For some test that I have been running, which was using record length=633, the speed of the query doubled thanks to this change. Other things: - Fixed calculation of max_records passed to hp_create() to take into account padding between records. - Updated calculation of memory needed by heap tables. Before we did not take into account internal structures needed to access rows. - Changed block sized for memory_table from 1 to 16384 to get less fragmentation. This also avoids a problem where we need 1K to manage index and row storage which was not counted for before. - Moved heap memory usage to a separate test for 32 bit. - Allocate all data blocks in heap in powers of 2. Change reported memory usage for heap to reflect this. Reviewed-by: Sergei Golubchik <serg@mariadb.org>
5 lines
187 B
Text
5 lines
187 B
Text
--maximum-auto-increment-increment=8192
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--maximum-tmp-table-size=16384
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--maximum-max-join-size=8192
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--maximum-use-stat-tables=COMPLEMENTARY
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--maximum-sql-mode='REAL_AS_FLOAT,ANSI_QUOTES'
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