• records_in_range start_key, end_key


    select * from federatedTest where name='aaa';
    (gdb) p *start_key
    $2 = {key = 0x7f64f4103be8 "", length = 23, keypart_map = 1, flag = HA_READ_KEY_EXACT}
    (gdb) p *end_key
    $3 = {key = 0x7f64f4104ae6 "", length = 23, keypart_map = 1, flag = HA_READ_AFTER_KEY}

    select * from federatedTest use index (idx_name_age) where name='aaa' and age=10;
    (gdb) p *start_key
    $6 = {key = 0x7f64f4103be8 "", length = 28, keypart_map = 3, flag = HA_READ_KEY_EXACT}
    (gdb) p *end_key
    $7 = {key = 0x7f64f4104ae6 "", length = 28, keypart_map = 3, flag = HA_READ_AFTER_KEY}

    select * from federatedTest use index (idx_name_age) where name='aaa' and age>10;
    (gdb) p *start_key
    $8 = {key = 0x7f64f4103be8 "", length = 28, keypart_map = 3, flag = HA_READ_AFTER_KEY}
    (gdb) p *end_key
    $9 = {key = 0x7f64f4104ae6 "", length = 23, keypart_map = 1, flag = HA_READ_AFTER_KEY}

    select * from federatedTest use index (idx_name_age) where name > 'aaa' ;
    (gdb) p *start_key
    $10 = {key = 0x7f64f4103be8 "", length = 23, keypart_map = 1, flag = HA_READ_AFTER_KEY}
    (gdb) p *end_key
    Cannot access memory at address 0x0

    select * from federatedTest use index (idx_name_age) where name > 'aaa' and age >10;
    $11 = {key = 0x7f64f4103be8 "", length = 23, keypart_map = 1, flag = HA_READ_AFTER_KEY}
    (gdb) p *end_key
    Cannot access memory at address 0x0

    select * from federatedTest use index (idx_name_age) where name > 'aaa' and age <10;
    (gdb) p *start_key
    $12 = {key = 0x7f64f4103be8 "", length = 23, keypart_map = 1, flag = HA_READ_AFTER_KEY}
    (gdb) p *end_key
    Cannot access memory at address 0x0
    (gdb)

    select * from federatedTest use index (idx_name_age) where name = 'aaa' and age <10;
    (gdb) p *start_key
    $13 = {key = 0x7f64f4103be8 "", length = 28, keypart_map = 3, flag = HA_READ_AFTER_KEY}
    (gdb) p *end_key
    $14 = {key = 0x7f64f4104ae6 "", length = 28, keypart_map = 3, flag = HA_READ_BEFORE_KEY}

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  • 原文地址:https://www.cnblogs.com/youge-OneSQL/p/9679695.html
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