mirror of
https://github.com/MariaDB/server.git
synced 2025-01-16 03:52:35 +01:00
b753ac066b
This task deals with packing the sort key inside the sort buffer, which would
lead to efficient usage of the memory allocated for the sort buffer.
The changes brought by this feature are
1) Sort buffers would have sort keys of variable length
2) The format for sort keys inside the sort buffer would look like
|<sort_length><null_byte><key_part1><null_byte><key_part2>.......|
sort_length is the extra bytes that are required to store the variable
length of a sort key.
3) When packing of sort key is done we store the ORIGINAL VALUES inside
the sort buffer and not the STRXFRM form (mem-comparable sort keys).
4) Special comparison function packed_keys_comparison() is introduced
to compare 2 sort keys.
This patch also contains contributions from Sergei Petrunia.
499 lines
15 KiB
Text
499 lines
15 KiB
Text
set @save_rand_seed1= @@RAND_SEED1;
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set @save_rand_seed2= @@RAND_SEED2;
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set @@RAND_SEED1=810763568, @@RAND_SEED2=600681772;
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create table t1(a int);
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insert into t1 select seq from seq_1_to_10000 order by rand(),seq;
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#
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# parameters:
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# mean mean for the column to be considered
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# max_val max_value for the column to be considered
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#
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# This function generate a sample of a normal distribution
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# This function return a point
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# of the normal distribution with a given mean.
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#
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CREATE FUNCTION
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generate_normal_distribution_sample(mean DOUBLE, max_val DOUBLE)RETURNS DOUBLE
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BEGIN
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DECLARE z DOUBLE DEFAULT 0;
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SET z= (rand() + rand() + rand() + rand() + rand() + rand())/6;
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SET z= 2*(max_val-mean)*z;
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SET z= z + mean - (max_val-mean);
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return z;
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END|
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#
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# parameters:
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# len length of the random string to be generated
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#
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# This function generates a random string for the length passed
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# as an argument with characters in the range of [A,Z]
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#
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CREATE FUNCTION generate_random_string(len INT) RETURNS varchar(128)
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BEGIN
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DECLARE str VARCHAR(256) DEFAULT '';
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DECLARE x INT DEFAULT 0;
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WHILE (len > 0) DO
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SET x =round(rand()*25);
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SET str= CONCAT(str, CHAR(65 + x));
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SET len= len-1;
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END WHILE;
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RETURN str;
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END|
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#
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# parameters:
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# mean mean for the column to be considered
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# min_val min_value for the column to be considered
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# max_val max_value for the column to be considered
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#
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# This function generate a normal distribution sample in the range of
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# [min_val, max_val]
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#
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CREATE FUNCTION
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clipped_normal_distribution(mean DOUBLE, min_val DOUBLE, max_val DOUBLE)
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RETURNS INT
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BEGIN
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DECLARE r DOUBLE DEFAULT 0;
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WHILE 1=1 DO
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set r= generate_normal_distribution_sample(mean, max_val);
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IF (r >= min_val AND r <= max_val) THEN
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RETURN round(r);
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end if;
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END WHILE;
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RETURN 0;
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END|
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create table t2 (id INT NOT NULL, a INT, b int);
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insert into t2
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select a, clipped_normal_distribution(12, 0, 64),
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clipped_normal_distribution(32, 0, 128)
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from t1;
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CREATE TABLE t3(
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id INT NOT NULL,
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names VARCHAR(64),
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address VARCHAR(128),
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PRIMARY KEY (id)
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);
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#
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# table t3 stores random strings calculated from the length stored in
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# table t2
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#
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insert into t3
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select id, generate_random_string(a), generate_random_string(b) from t2;
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#
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# All records fit in memory
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#
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set sort_buffer_size=262144*10;
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analyze format=json select id DIV 100 as x,
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MD5(group_concat(substring(names,1,3), substring(address,1,3)
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order by id))
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FROM t3
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GROUP BY x;
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ANALYZE
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{
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"query_block": {
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"select_id": 1,
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"r_loops": 1,
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"r_total_time_ms": "REPLACED",
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"read_sorted_file": {
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"r_rows": 10000,
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"filesort": {
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"sort_key": "t3.`id` DIV 100",
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"r_loops": 1,
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"r_total_time_ms": "REPLACED",
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"r_used_priority_queue": false,
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"r_output_rows": 10000,
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"r_buffer_size": "REPLACED",
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"r_sort_mode": "sort_key,packed_addon_fields",
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"table": {
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"table_name": "t3",
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"access_type": "ALL",
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"r_loops": 1,
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"rows": 10000,
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"r_rows": 10000,
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"r_table_time_ms": "REPLACED",
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"r_other_time_ms": "REPLACED",
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"filtered": 100,
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"r_filtered": 100
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}
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}
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}
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}
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}
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flush status;
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select id DIV 100 as x,
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MD5(group_concat(substring(names,1,3), substring(address,1,3)
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order by id))
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FROM t3
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GROUP BY x;
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x MD5(group_concat(substring(names,1,3), substring(address,1,3)
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order by id))
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0 3d24cb0237caf81aa74a2dddf367ac23
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1 618f9b8b6cefaa268dcb5477eece5e90
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2 fbfe93cc7713f852852f66e578d999aa
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3 34802712af9c95664f41e789d19fb6e7
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5 324b8e682ad2233498f36979fddddf30
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6 31ccc1ab69c00dcade71f7fda2fad599
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22 1d0cb7cd3f54c15bd41491e6fa449f12
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23 15f95be2574a94677fa7e76ead23e025
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27 cfd45d4915f342978fb6982a825f6cc2
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28 2bd8981c6245c32ea1dc27ef394df94e
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29 0e47838fe4be239939424fcef1289002
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30 18e291b42da10b04434bdad010a5b66c
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31 cbd1bf2554378ef7edd9087d4a8562d4
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32 ddb1e7282bb637f7fe3aa3aed149b482
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33 1963f2400c8870d67f99c391bc5040c2
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34 d2b44d3c13a7a2c83de840892a370f47
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36 685fbfc47faad4243944d7331a2dee36
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37 9d58b82b5f9d369a16c4f2bcc424b412
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53 2125a788f107a4ba6a364984f7145156
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67 d6a2aa26124dd42a9df9fa21b7eb8bce
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70 f5f7aa5569558b3e6556c72c9dfc429b
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71 9e1cc67e0c13d00c771b6bed2fd566cf
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72 3a6e7c6ce76a04fa2503d094121d84d5
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73 5fd8ba2dd8d36814d06a1d278002e437
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74 10db883700dde7289eb640df3a6d6676
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75 3ebd59ed119d6dfda3eedc5bf05fd425
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76 5008d3ce585f3b2dda2b313c57ebcb0a
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85 272a5d09070b5a0569fb18e144100f8b
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86 0f969fd16dd186e9eb099213a82fb119
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87 6c48f63ec50e26ba42d8ca074daee9a6
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89 c57cf49bbeaa12aaba2106278681c9cd
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90 d248507181561f0aba09182c4326fb11
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91 a1e153dd8bb1334bccd73890fafc5ba9
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92 d7a0ba2d1241a07abf3691074cecff76
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93 466034794d577c41a9716bc9eb903ee2
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94 b5e2158feb4290b04a7bdfdec0a17976
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95 8a16a27008d033dd6e9074b042021e60
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96 ccaa12e89f6de3058b3a2baddc4eff00
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97 7fdbf02f369546d0fde2b7db85752e33
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98 63b286bb777298397f3acf03fc3e9deb
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99 b271f751a4952f86b002b9730bd02c8b
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100 cbd5cef546acc0bfa33117d7c1ae58a8
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show status like '%sort%';
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Variable_name Value
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Sort_merge_passes 0
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Sort_priority_queue_sorts 0
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Sort_range 0
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Sort_rows 10000
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Sort_scan 1
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set sort_buffer_size=default;
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#
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# Test for merge_many_buff
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#
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set sort_buffer_size=32768;
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analyze format=json select id DIV 100 as x,
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MD5(group_concat(substring(names,1,3), substring(address,1,3)
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order by id))
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FROM t3
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GROUP BY x;
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ANALYZE
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{
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"query_block": {
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"select_id": 1,
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"r_loops": 1,
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"r_total_time_ms": "REPLACED",
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"read_sorted_file": {
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"r_rows": 10000,
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"filesort": {
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"sort_key": "t3.`id` DIV 100",
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"r_loops": 1,
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"r_total_time_ms": "REPLACED",
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"r_used_priority_queue": false,
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"r_output_rows": 10000,
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"r_sort_passes": 4,
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"r_buffer_size": "REPLACED",
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"r_sort_mode": "sort_key,packed_addon_fields",
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"table": {
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"table_name": "t3",
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"access_type": "ALL",
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"r_loops": 1,
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"rows": 10000,
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"r_rows": 10000,
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"r_table_time_ms": "REPLACED",
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"r_other_time_ms": "REPLACED",
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"filtered": 100,
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"r_filtered": 100
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}
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}
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}
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}
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}
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flush status;
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select id DIV 100 as x,
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MD5(group_concat(substring(names,1,3), substring(address,1,3)
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order by id))
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FROM t3
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GROUP BY x;
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x MD5(group_concat(substring(names,1,3), substring(address,1,3)
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order by id))
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0 3d24cb0237caf81aa74a2dddf367ac23
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1 618f9b8b6cefaa268dcb5477eece5e90
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2 fbfe93cc7713f852852f66e578d999aa
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3 34802712af9c95664f41e789d19fb6e7
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4 2d9a4d628013b45cea5301143ec559c5
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5 324b8e682ad2233498f36979fddddf30
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6 31ccc1ab69c00dcade71f7fda2fad599
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7 e059e0279a5654a1c5f6596d220691bf
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8 a21e5021cfb19be280f7fa2c2e70608e
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9 6230b389a5bb0f9cd464b839e8824d0d
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10 f2db66b6c4ad49e406f965a80ff5d224
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11 75f39127d968cad28d30707889191d81
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12 2e75191c0f32966a9e7675d0ddcf1c1c
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13 808b4ecabb9cbb40ff3549c81b21d2f5
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14 c7c0c0bbf0ab7558793a86eaca714a3f
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16 13b1b17e93649fe49d6da356c2072c63
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17 e3ce0af10608e6467ba4d38b135ff873
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18 0f172b310ad772e13630b647e09ef79a
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19 26bbfb77888fa151215fe8ff75e448e7
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20 fcd6d5113e8178766dc370b470eb053a
|
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21 d3860a17be6da02e17432f2ff80a261f
|
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22 1d0cb7cd3f54c15bd41491e6fa449f12
|
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|
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72 3a6e7c6ce76a04fa2503d094121d84d5
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73 5fd8ba2dd8d36814d06a1d278002e437
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74 10db883700dde7289eb640df3a6d6676
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75 3ebd59ed119d6dfda3eedc5bf05fd425
|
|
76 5008d3ce585f3b2dda2b313c57ebcb0a
|
|
77 ac7cee33e39827de02acedb7584acae5
|
|
78 3f440facefbd95f905942c75bfe60bbb
|
|
79 89639b3145c988c775d9d997c9d356ff
|
|
80 a6f8b29a83b2305188c241f2724ea998
|
|
81 d79f9bd47505cee69627e8044f7745c2
|
|
82 5f8d8b55bc9d5b44f817ada0b9bab2f7
|
|
83 411a99ef2e2af45640f0224274979fb5
|
|
84 60706cd1eb7dffae3d7a34133c5cb67e
|
|
85 272a5d09070b5a0569fb18e144100f8b
|
|
86 0f969fd16dd186e9eb099213a82fb119
|
|
87 6c48f63ec50e26ba42d8ca074daee9a6
|
|
88 83512539cc5a2561426564590d307a58
|
|
89 c57cf49bbeaa12aaba2106278681c9cd
|
|
90 d248507181561f0aba09182c4326fb11
|
|
91 a1e153dd8bb1334bccd73890fafc5ba9
|
|
92 d7a0ba2d1241a07abf3691074cecff76
|
|
93 466034794d577c41a9716bc9eb903ee2
|
|
94 b5e2158feb4290b04a7bdfdec0a17976
|
|
95 8a16a27008d033dd6e9074b042021e60
|
|
96 ccaa12e89f6de3058b3a2baddc4eff00
|
|
97 7fdbf02f369546d0fde2b7db85752e33
|
|
98 63b286bb777298397f3acf03fc3e9deb
|
|
99 b271f751a4952f86b002b9730bd02c8b
|
|
100 cbd5cef546acc0bfa33117d7c1ae58a8
|
|
show status like '%sort%';
|
|
Variable_name Value
|
|
Sort_merge_passes 4
|
|
Sort_priority_queue_sorts 0
|
|
Sort_range 0
|
|
Sort_rows 10000
|
|
Sort_scan 1
|
|
set sort_buffer_size=default;
|
|
#
|
|
# CASE #1 Packed sort keys with addon fields
|
|
#
|
|
ALTER TABLE t3 ADD INDEX idx(names, address);
|
|
set sort_buffer_size= 2097152;
|
|
ANALYZE FORMAT=JSON SELECT id, names, address FROM t3 ORDER BY names, address;
|
|
ANALYZE
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"r_loops": 1,
|
|
"r_total_time_ms": "REPLACED",
|
|
"read_sorted_file": {
|
|
"r_rows": 10000,
|
|
"filesort": {
|
|
"sort_key": "t3.`names`, t3.address",
|
|
"r_loops": 1,
|
|
"r_total_time_ms": "REPLACED",
|
|
"r_used_priority_queue": false,
|
|
"r_output_rows": 10000,
|
|
"r_buffer_size": "REPLACED",
|
|
"r_sort_mode": "packed_sort_key,packed_addon_fields",
|
|
"table": {
|
|
"table_name": "t3",
|
|
"access_type": "ALL",
|
|
"r_loops": 1,
|
|
"rows": 10000,
|
|
"r_rows": 10000,
|
|
"r_table_time_ms": "REPLACED",
|
|
"r_other_time_ms": "REPLACED",
|
|
"filtered": 100,
|
|
"r_filtered": 100
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
flush status;
|
|
SELECT id, names, address INTO OUTFILE '$file1' FROM t3 ORDER BY names, address;
|
|
# Sort_merge_passes should be 0
|
|
show status like '%sort%';
|
|
Variable_name Value
|
|
Sort_merge_passes 0
|
|
Sort_priority_queue_sorts 0
|
|
Sort_range 0
|
|
Sort_rows 10000
|
|
Sort_scan 1
|
|
SELECT id, names, address INTO OUTFILE '$file2' FROM t3 FORCE INDEX(idx) ORDER BY names, address;
|
|
#
|
|
# CASE #2 Packed sort keys and ROW_ID
|
|
#
|
|
set @save_max_length_for_sort_data=@@max_length_for_sort_data;
|
|
set max_length_for_sort_data= 300;
|
|
set sort_buffer_size= 1097152;
|
|
ANALYZE FORMAT=JSON SELECT id, names, address FROM t3 ORDER BY names, address;
|
|
ANALYZE
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"r_loops": 1,
|
|
"r_total_time_ms": "REPLACED",
|
|
"read_sorted_file": {
|
|
"r_rows": 10000,
|
|
"filesort": {
|
|
"sort_key": "t3.`names`, t3.address",
|
|
"r_loops": 1,
|
|
"r_total_time_ms": "REPLACED",
|
|
"r_used_priority_queue": false,
|
|
"r_output_rows": 10000,
|
|
"r_buffer_size": "REPLACED",
|
|
"r_sort_mode": "packed_sort_key,rowid",
|
|
"table": {
|
|
"table_name": "t3",
|
|
"access_type": "ALL",
|
|
"r_loops": 1,
|
|
"rows": 10000,
|
|
"r_rows": 10000,
|
|
"r_table_time_ms": "REPLACED",
|
|
"r_other_time_ms": "REPLACED",
|
|
"filtered": 100,
|
|
"r_filtered": 100
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
flush status;
|
|
SELECT id, names, address INTO OUTFILE '$file1' FROM t3 ORDER BY names, address;
|
|
# Sort_merge_passes should be 0
|
|
show status like '%sort%';
|
|
Variable_name Value
|
|
Sort_merge_passes 0
|
|
Sort_priority_queue_sorts 0
|
|
Sort_range 0
|
|
Sort_rows 10000
|
|
Sort_scan 1
|
|
set @@max_length_for_sort_data=@save_max_length_for_sort_data;
|
|
set @@sort_buffer_size=default;
|
|
set @@RAND_SEED1= @save_rand_seed1;
|
|
set @@RAND_SEED2= @save_rand_seed2;
|
|
drop function generate_normal_distribution_sample;
|
|
drop function generate_random_string;
|
|
drop function clipped_normal_distribution;
|
|
drop table t1, t2, t3;
|