本文介绍GBase 8a的为精确查询提供的Global hash索引查询性能提升测试。
目录导航
测试结果
global hash索引，可以提升简单精确查询的性能10-100倍。 其中重复度越低，性能提升效果越好。
环境
硬件
笔记本的虚拟机， 4C, 4G. redhat 7
版本
9.5.2, 该功能没有做过改动。
数据
2字段表，1.2亿行，其中id有32K个不同值，name 有1亿个不通值。
gbase> desc tt1;
+-------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+--------------+------+-----+---------+-------+
| id | int(11) | YES | | NULL | |
| name | varchar(100) | YES | | NULL | |
+-------+--------------+------+-----+---------+-------+
2 rows in set (Elapsed: 00:00:00.00)
gbase> select count(*), count(distinct id),count(distinct name) from tt1;
+-----------+--------------------+----------------------+
| count(*) | count(distinct id) | count(distinct name) |
+-----------+--------------------+----------------------+
| 127135509 | 32768 | 10000002 |
+-----------+--------------------+----------------------+
1 row in set (Elapsed: 00:06:52.89)测试过程
无索引查询id
结果集3700行，基本在0.4-0.5秒。
gbase> select count(*) from tt1 where id=10;
+----------+
| count(*) |
+----------+
| 3717 |
+----------+
1 row in set (Elapsed: 00:00:00.88)
gbase> select count(*) from tt1 where id=10;
+----------+
| count(*) |
+----------+
| 3717 |
+----------+
1 row in set (Elapsed: 00:00:00.46)
gbase> select count(*) from tt1 where id=10;
+----------+
| count(*) |
+----------+
| 3717 |
+----------+
1 row in set (Elapsed: 00:00:00.47)从trc日志看，首次加载了几百个DC,然后扫描，耗时0.4秒。 后续是热数据，时间0.4秒花费纯扫描上。
SELECT COUNT(1) FROM `testdb`.`tt1_n1` `vcname000001.testdb.tt1` WHERE (`vcname000001.testdb.tt1`.`id` = 10)
2021-08-16 08:51:02.062 [M: 0B, 0B,D: 0B] [DC: 0, 0] Start Query Execution
2021-08-16 08:51:02.062 [M: 0B, 0B,D: 0B] [DC: 0, 0] Tables:
2021-08-16 08:51:02.062 [M: 0B, 0B,D: 0B] [DC: 0, 0] T0: vcname000001.testdb.tt1(testdb.tt1_n1), 63567786 rows, 970 DC
2021-08-16 08:51:02.062 [M: 0B, 0B,D: 0B] [DC: 0, 0] Condition Weight (non-join):
2021-08-16 08:51:02.062 [M: 0B, 0B,D: 0B] [DC: 0, 0] cnd(0): vcname000001.testdb.tt1.id BET. 10 AND 10 (0)
2021-08-16 08:51:02.062 [M: 0B, 0B,D: 0B] [DC: 0, 0] BEGIN Smart Scan
2021-08-16 08:51:02.062 [M: 0B, 0B,D: 0B] [DC: 0, 0] T0: total 970 DC, found 970 DC to scan(with 0 FULL DC).
2021-08-16 08:51:02.062 [M: 0B, 0B,D: 0B] [DC: 0, 0] END Smart Scan. (time used: 0.000s)
2021-08-16 08:51:02.062 [M: 0B, 0B,D: 0B] [DC: 0, 0] BEGIN Scan
2021-08-16 08:51:02.062 [M: 0B, 0B,D: 0B] [DC: 0, 0] cnd(0) vcname000001.testdb.tt1.id BET. 10 AND 10
2021-08-16 08:51:02.628 [M: 139M, 0B,D: 0B] [DC: 2, 508] ( 1)cnd(0) scanned 15859712 rows, found 469 rows (time used: 0.565s)
2021-08-16 08:51:02.832 [M: 229M, 0B,D: 0B] [DC: 0, 859] ( 2)cnd(0) scanned 15925248 rows, found 461 rows (time used: 0.769s)
2021-08-16 08:51:02.873 [M: 247M, 0B,D: 0B] [DC: 0, 947] ( 0)cnd(0) scanned 15925248 rows, found 460 rows (time used: 0.811s)
2021-08-16 08:51:02.897 [M: 254M, 0B,D: 0B] [DC: 0, 970] ( 3)cnd(0) scanned 15857578 rows, found 477 rows (time used: 0.835s)
2021-08-16 08:51:02.900 [M: 254M, 0B,D: 0B] [DC: 0, 970] cnd(0) Done. scanned 63567786 rows, found 1867 rows (time used: 0.838s)
2021-08-16 08:51:02.901 [M: 255M, 0B,D: 0B] [DC: 0, 970] T0: total 970 DC, found 828 DC after scan(with 0 FULL DC).
2021-08-16 08:51:02.901 [M: 255M, 0B,D: 0B] [DC: 0, 970] END Scan. (time used: 0.839s)
2021-08-16 08:51:02.901 [M: 255M, 0B,D: 0B] [DC: 0, 970] Condition Weight (join):
2021-08-16 08:51:02.901 [M: 255M, 0B,D: 0B] [DC: 0, 970] BEGIN Join
2021-08-16 08:51:02.901 [M: 255M, 0B,D: 0B] [DC: 0, 970] END Join(time used: 0.000s)
2021-08-16 08:51:02.901 [M: 255M, 0B,D: 0B] [DC: 0, 970] BEGIN Scan(after join)
2021-08-16 08:51:02.901 [M: 255M, 0B,D: 0B] [DC: 0, 970] END Scan(after join)(time used: 0.000s)
2021-08-16 08:51:02.901 [M: 255M, 0B,D: 0B] [DC: 0, 970] CalculatePageSize: TmpCacheSize = 32000000, no obj = 63567786, attr count = 1, record size = 8, page size = 4194304
2021-08-16 08:51:02.901 [M: 255M, 32B,D: 0B] [DC: 0, 970] GTBuff: total_size:33554432 has_dist:0 rows_limit:1 width:8
2021-08-16 08:51:02.901 [M: 255M, 0B,D: 0B] [DC: 0, 970] BEGIN Serial Aggregation(1867 rows)
2021-08-16 08:51:02.901 [M: 255M, 32B,D: 0B] [DC: 0, 970] GTBuff: total_size:33554432 has_dist:0 rows_limit:1 width:8
2021-08-16 08:51:02.901 [M: 255M, 64B,D: 0B] [DC: 0, 970] GTBuff: total_size:33554432 has_dist:0 rows_limit:1 width:8
2021-08-16 08:51:02.901 [M: 255M, 32B,D: 0B] [DC: 0, 970] BEGIN Aggregation(1867 rows)
2021-08-16 08:51:02.901 [M: 255M, 64B,D: 0B] [DC: 0, 970] GTBuff: total_size:33554432 has_dist:0 rows_limit:1 width:8
2021-08-16 08:51:02.901 [M: 255M, 64B,D: 0B] [DC: 0, 970] TempTable::MultiDimensionalGroupByScan(): aggregate 1867 rows)
2021-08-16 08:51:02.901 [M: 255M, 64B,D: 0B] [DC: 0, 970] CalculatePageSize: TmpCacheSize = 32000000, no obj = 1, attr count = 1, record size = 8, page size = 65536
2021-08-16 08:51:02.901 [M: 255M, 64B,D: 0B] [DC: 0, 970] CalculatePageSize: TmpCacheSize = 32000000, no obj = 1, attr count = 1, record size = 8, page size = 65536
2021-08-16 08:51:02.901 [M: 255M, 32B,D: 0B] [DC: 0, 970] END Serial Aggregation. (time used: 0.000s)
2021-08-16 08:51:02.901 [M: 255M, 0B,D: 0B] [DC: 1, 970] Send 1 rows already
2021-08-16 08:51:02.902 [M: 255M, 0B,D: 0B] [DC: 1, 970] CalculatePageSize: TmpCacheSize = 32000000, no obj = 65536, attr count = 1, record size = 8, page size = 65536
2021-08-16 08:51:02.902 [M: 255M, 0B,D: 0B] [DC: 1, 970] ResultSender: send 0 rows.
2021-08-16 08:51:02.902 [M: 255M, 0B,D: 0B] [DC: 1, 970] output result done.
2021-08-16 08:51:02.902 [M: 255M, 0B,D: 0B] [DC: 1, 970] SUMMARY
2021-08-16 08:51:02.902 [M: 255M, 0B,D: 0B] [DC: 1, 970] elapsed time: 00:00:00.840
2021-08-16 08:51:02.902 [M: 255M, 0B,D: 0B] [DC: 1, 970] data loaded from storage: 123M, 2.169s, 970 DC.
2021-08-16 08:51:02.902 [M: 255M, 0B,D: 0B] [DC: 1, 970] data decompressed: 134M, 0.028s.
2021-08-16 08:51:02.902 [M: 255M, 0B,D: 0B] [DC: 1, 970] temp space IO stats:
2021-08-16 08:51:02.902 [M: 255M, 0B,D: 0B] [DC: 1, 970] CB write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 08:51:02.902 [M: 255M, 0B,D: 0B] [DC: 1, 970] SRT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 08:51:02.902 [M: 255M, 0B,D: 0B] [DC: 1, 970] GDC write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 08:51:02.902 [M: 255M, 0B,D: 0B] [DC: 1, 970] MAT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 08:51:02.902 [M: 255M, 0B,D: 0B] [DC: 1, 970] HSJ write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 08:51:02.902 [M: 255M, 0B,D: 0B] [DC: 1, 970] ======================================================
2021-08-16 08:51:07.970 [M: 261M, 0B,D: 0B] [DC: 1, 970] before opt:select count(1) AS "COUNT(1)" from "testdb"."tt1_n1" "vcname000001.testdb.tt1" where ("testdb"."vcname000001.testdb.tt1"."id" = 10)
2021-08-16 08:51:07.970 [M: 261M, 0B,D: 0B] [DC: 1, 970] after opt:select count(1) AS "COUNT(1)" from "testdb"."tt1_n1" "vcname000001.testdb.tt1" where ("testdb"."vcname000001.testdb.tt1"."id" = 10)
2021-08-16 08:51:07.970 [M: 261M, 0B,D: 0B] [DC: 0, 0] SQL Statement:
SELECT COUNT(1) FROM `testdb`.`tt1_n1` `vcname000001.testdb.tt1` WHERE (`vcname000001.testdb.tt1`.`id` = 10)
2021-08-16 08:51:07.970 [M: 261M, 0B,D: 0B] [DC: 0, 0] Start Query Execution
2021-08-16 08:51:07.970 [M: 261M, 0B,D: 0B] [DC: 0, 0] Tables:
2021-08-16 08:51:07.970 [M: 261M, 0B,D: 0B] [DC: 0, 0] T0: vcname000001.testdb.tt1(testdb.tt1_n1), 63567786 rows, 970 DC
2021-08-16 08:51:07.970 [M: 261M, 0B,D: 0B] [DC: 0, 0] Condition Weight (non-join):
2021-08-16 08:51:07.970 [M: 261M, 0B,D: 0B] [DC: 0, 0] cnd(0): vcname000001.testdb.tt1.id BET. 10 AND 10 (0)
2021-08-16 08:51:07.970 [M: 261M, 0B,D: 0B] [DC: 0, 0] BEGIN Smart Scan
2021-08-16 08:51:07.970 [M: 261M, 0B,D: 0B] [DC: 0, 0] T0: total 970 DC, found 970 DC to scan(with 0 FULL DC).
2021-08-16 08:51:07.970 [M: 261M, 0B,D: 0B] [DC: 0, 0] END Smart Scan. (time used: 0.000s)
2021-08-16 08:51:07.970 [M: 261M, 0B,D: 0B] [DC: 0, 0] BEGIN Scan
2021-08-16 08:51:07.970 [M: 261M, 0B,D: 0B] [DC: 0, 0] cnd(0) vcname000001.testdb.tt1.id BET. 10 AND 10
2021-08-16 08:51:08.201 [M: 261M, 0B,D: 0B] [DC: 612, 0] ( 0)cnd(0) scanned 15925248 rows, found 460 rows (time used: 0.230s)
2021-08-16 08:51:08.390 [M: 261M, 0B,D: 0B] [DC: 951, 0] ( 2)cnd(0) scanned 15925248 rows, found 461 rows (time used: 0.409s)
2021-08-16 08:51:08.393 [M: 261M, 0B,D: 0B] [DC: 953, 0] ( 1)cnd(0) scanned 15859712 rows, found 469 rows (time used: 0.422s)
2021-08-16 08:51:08.408 [M: 261M, 0B,D: 0B] [DC: 970, 0] ( 3)cnd(0) scanned 15857578 rows, found 477 rows (time used: 0.428s)
2021-08-16 08:51:08.411 [M: 261M, 0B,D: 0B] [DC: 970, 0] cnd(0) Done. scanned 63567786 rows, found 1867 rows (time used: 0.440s)
2021-08-16 08:51:08.412 [M: 261M, 0B,D: 0B] [DC: 970, 0] T0: total 970 DC, found 828 DC after scan(with 0 FULL DC).
2021-08-16 08:51:08.412 [M: 261M, 0B,D: 0B] [DC: 970, 0] END Scan. (time used: 0.441s)
2021-08-16 08:51:08.412 [M: 261M, 0B,D: 0B] [DC: 970, 0] Condition Weight (join):
2021-08-16 08:51:08.412 [M: 261M, 0B,D: 0B] [DC: 970, 0] BEGIN Join
2021-08-16 08:51:08.412 [M: 261M, 0B,D: 0B] [DC: 970, 0] END Join(time used: 0.000s)
2021-08-16 08:51:08.412 [M: 261M, 0B,D: 0B] [DC: 970, 0] BEGIN Scan(after join)
2021-08-16 08:51:08.412 [M: 261M, 0B,D: 0B] [DC: 970, 0] END Scan(after join)(time used: 0.000s)
2021-08-16 08:51:08.412 [M: 261M, 0B,D: 0B] [DC: 970, 0] CalculatePageSize: TmpCacheSize = 32000000, no obj = 63567786, attr count = 1, record size = 8, page size = 4194304
2021-08-16 08:51:08.412 [M: 261M, 32B,D: 0B] [DC: 970, 0] GTBuff: total_size:33554432 has_dist:0 rows_limit:1 width:8
2021-08-16 08:51:08.412 [M: 261M, 0B,D: 0B] [DC: 970, 0] BEGIN Serial Aggregation(1867 rows)
2021-08-16 08:51:08.412 [M: 261M, 32B,D: 0B] [DC: 970, 0] GTBuff: total_size:33554432 has_dist:0 rows_limit:1 width:8
2021-08-16 08:51:08.412 [M: 261M, 64B,D: 0B] [DC: 970, 0] GTBuff: total_size:33554432 has_dist:0 rows_limit:1 width:8
2021-08-16 08:51:08.412 [M: 261M, 32B,D: 0B] [DC: 970, 0] BEGIN Aggregation(1867 rows)
2021-08-16 08:51:08.412 [M: 261M, 64B,D: 0B] [DC: 970, 0] GTBuff: total_size:33554432 has_dist:0 rows_limit:1 width:8
2021-08-16 08:51:08.412 [M: 261M, 64B,D: 0B] [DC: 970, 0] TempTable::MultiDimensionalGroupByScan(): aggregate 1867 rows)
2021-08-16 08:51:08.412 [M: 261M, 64B,D: 0B] [DC: 970, 0] CalculatePageSize: TmpCacheSize = 32000000, no obj = 1, attr count = 1, record size = 8, page size = 65536
2021-08-16 08:51:08.412 [M: 261M, 64B,D: 0B] [DC: 970, 0] CalculatePageSize: TmpCacheSize = 32000000, no obj = 1, attr count = 1, record size = 8, page size = 65536
2021-08-16 08:51:08.412 [M: 262M, 32B,D: 0B] [DC: 970, 0] END Serial Aggregation. (time used: 0.000s)
2021-08-16 08:51:08.412 [M: 262M, 0B,D: 0B] [DC: 971, 0] Send 1 rows already
2021-08-16 08:51:08.412 [M: 261M, 0B,D: 0B] [DC: 971, 0] CalculatePageSize: TmpCacheSize = 32000000, no obj = 65536, attr count = 1, record size = 8, page size = 65536
2021-08-16 08:51:08.412 [M: 261M, 0B,D: 0B] [DC: 971, 0] ResultSender: send 0 rows.
2021-08-16 08:51:08.412 [M: 261M, 0B,D: 0B] [DC: 971, 0] output result done.
2021-08-16 08:51:08.413 [M: 261M, 0B,D: 0B] [DC: 971, 0] SUMMARY
2021-08-16 08:51:08.413 [M: 261M, 0B,D: 0B] [DC: 971, 0] elapsed time: 00:00:00.443
2021-08-16 08:51:08.413 [M: 261M, 0B,D: 0B] [DC: 971, 0] data loaded from storage: 0B, 0s, 0 DC.
2021-08-16 08:51:08.413 [M: 261M, 0B,D: 0B] [DC: 971, 0] data decompressed: 0B, 0s.
2021-08-16 08:51:08.413 [M: 261M, 0B,D: 0B] [DC: 971, 0] temp space IO stats:
2021-08-16 08:51:08.413 [M: 261M, 0B,D: 0B] [DC: 971, 0] CB write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 08:51:08.413 [M: 261M, 0B,D: 0B] [DC: 971, 0] SRT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 08:51:08.413 [M: 261M, 0B,D: 0B] [DC: 971, 0] GDC write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 08:51:08.413 [M: 261M, 0B,D: 0B] [DC: 971, 0] MAT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 08:51:08.413 [M: 261M, 0B,D: 0B] [DC: 971, 0] HSJ write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 08:51:08.413 [M: 261M, 0B,D: 0B] [DC: 971, 0] ======================================================
2021-08-16 08:51:10.611 [M: 261M, 0B,D: 0B] [DC: 971, 0] before opt:select count(1) AS "COUNT(1)" from "testdb"."tt1_n1" "vcname000001.testdb.tt1" where ("testdb"."vcname000001.testdb.tt1"."id" = 10)
2021-08-16 08:51:10.611 [M: 261M, 0B,D: 0B] [DC: 971, 0] after opt:select count(1) AS "COUNT(1)" from "testdb"."tt1_n1" "vcname000001.testdb.tt1" where ("testdb"."vcname000001.testdb.tt1"."id" = 10)
2021-08-16 08:51:10.611 [M: 261M, 0B,D: 0B] [DC: 0, 0] SQL Statement:
SELECT COUNT(1) FROM `testdb`.`tt1_n1` `vcname000001.testdb.tt1` WHERE (`vcname000001.testdb.tt1`.`id` = 10)
2021-08-16 08:51:10.611 [M: 261M, 0B,D: 0B] [DC: 0, 0] Start Query Execution
2021-08-16 08:51:10.612 [M: 261M, 0B,D: 0B] [DC: 0, 0] Tables:
2021-08-16 08:51:10.612 [M: 261M, 0B,D: 0B] [DC: 0, 0] T0: vcname000001.testdb.tt1(testdb.tt1_n1), 63567786 rows, 970 DC
2021-08-16 08:51:10.612 [M: 261M, 0B,D: 0B] [DC: 0, 0] Condition Weight (non-join):
2021-08-16 08:51:10.612 [M: 261M, 0B,D: 0B] [DC: 0, 0] cnd(0): vcname000001.testdb.tt1.id BET. 10 AND 10 (0)
2021-08-16 08:51:10.612 [M: 261M, 0B,D: 0B] [DC: 0, 0] BEGIN Smart Scan
2021-08-16 08:51:10.612 [M: 261M, 0B,D: 0B] [DC: 0, 0] T0: total 970 DC, found 970 DC to scan(with 0 FULL DC).
2021-08-16 08:51:10.612 [M: 261M, 0B,D: 0B] [DC: 0, 0] END Smart Scan. (time used: 0.000s)
2021-08-16 08:51:10.612 [M: 261M, 0B,D: 0B] [DC: 0, 0] BEGIN Scan
2021-08-16 08:51:10.612 [M: 261M, 0B,D: 0B] [DC: 0, 0] cnd(0) vcname000001.testdb.tt1.id BET. 10 AND 10
2021-08-16 08:51:10.857 [M: 261M, 0B,D: 0B] [DC: 595, 0] ( 2)cnd(0) scanned 15925248 rows, found 461 rows (time used: 0.245s)
2021-08-16 08:51:10.966 [M: 261M, 0B,D: 0B] [DC: 833, 0] ( 0)cnd(0) scanned 15925248 rows, found 460 rows (time used: 0.345s)
2021-08-16 08:51:11.025 [M: 261M, 0B,D: 0B] [DC: 933, 0] ( 1)cnd(0) scanned 15859712 rows, found 469 rows (time used: 0.403s)
2021-08-16 08:51:11.055 [M: 261M, 0B,D: 0B] [DC: 970, 0] ( 3)cnd(0) scanned 15857578 rows, found 477 rows (time used: 0.433s)
2021-08-16 08:51:11.059 [M: 261M, 0B,D: 0B] [DC: 970, 0] cnd(0) Done. scanned 63567786 rows, found 1867 rows (time used: 0.447s)
2021-08-16 08:51:11.063 [M: 261M, 0B,D: 0B] [DC: 970, 0] T0: total 970 DC, found 828 DC after scan(with 0 FULL DC).
2021-08-16 08:51:11.063 [M: 261M, 0B,D: 0B] [DC: 970, 0] END Scan. (time used: 0.451s)
2021-08-16 08:51:11.063 [M: 261M, 0B,D: 0B] [DC: 970, 0] Condition Weight (join):
2021-08-16 08:51:11.063 [M: 261M, 0B,D: 0B] [DC: 970, 0] BEGIN Join
2021-08-16 08:51:11.063 [M: 261M, 0B,D: 0B] [DC: 970, 0] END Join(time used: 0.000s)
2021-08-16 08:51:11.063 [M: 261M, 0B,D: 0B] [DC: 970, 0] BEGIN Scan(after join)
2021-08-16 08:51:11.063 [M: 261M, 0B,D: 0B] [DC: 970, 0] END Scan(after join)(time used: 0.000s)
2021-08-16 08:51:11.063 [M: 261M, 0B,D: 0B] [DC: 970, 0] CalculatePageSize: TmpCacheSize = 32000000, no obj = 63567786, attr count = 1, record size = 8, page size = 4194304
2021-08-16 08:51:11.063 [M: 261M, 32B,D: 0B] [DC: 970, 0] GTBuff: total_size:33554432 has_dist:0 rows_limit:1 width:8
2021-08-16 08:51:11.063 [M: 261M, 0B,D: 0B] [DC: 970, 0] BEGIN Serial Aggregation(1867 rows)
2021-08-16 08:51:11.064 [M: 261M, 32B,D: 0B] [DC: 970, 0] GTBuff: total_size:33554432 has_dist:0 rows_limit:1 width:8
2021-08-16 08:51:11.064 [M: 261M, 64B,D: 0B] [DC: 970, 0] GTBuff: total_size:33554432 has_dist:0 rows_limit:1 width:8
2021-08-16 08:51:11.064 [M: 261M, 32B,D: 0B] [DC: 970, 0] BEGIN Aggregation(1867 rows)
2021-08-16 08:51:11.064 [M: 261M, 64B,D: 0B] [DC: 970, 0] GTBuff: total_size:33554432 has_dist:0 rows_limit:1 width:8
2021-08-16 08:51:11.064 [M: 261M, 64B,D: 0B] [DC: 970, 0] TempTable::MultiDimensionalGroupByScan(): aggregate 1867 rows)
2021-08-16 08:51:11.064 [M: 261M, 64B,D: 0B] [DC: 970, 0] CalculatePageSize: TmpCacheSize = 32000000, no obj = 1, attr count = 1, record size = 8, page size = 65536
2021-08-16 08:51:11.064 [M: 261M, 64B,D: 0B] [DC: 970, 0] CalculatePageSize: TmpCacheSize = 32000000, no obj = 1, attr count = 1, record size = 8, page size = 65536
2021-08-16 08:51:11.064 [M: 262M, 32B,D: 0B] [DC: 970, 0] END Serial Aggregation. (time used: 0.000s)
2021-08-16 08:51:11.064 [M: 262M, 0B,D: 0B] [DC: 971, 0] Send 1 rows already
2021-08-16 08:51:11.064 [M: 261M, 0B,D: 0B] [DC: 971, 0] CalculatePageSize: TmpCacheSize = 32000000, no obj = 65536, attr count = 1, record size = 8, page size = 65536
2021-08-16 08:51:11.064 [M: 261M, 0B,D: 0B] [DC: 971, 0] ResultSender: send 0 rows.
2021-08-16 08:51:11.064 [M: 261M, 0B,D: 0B] [DC: 971, 0] output result done.
2021-08-16 08:51:11.065 [M: 261M, 0B,D: 0B] [DC: 971, 0] SUMMARY
2021-08-16 08:51:11.065 [M: 261M, 0B,D: 0B] [DC: 971, 0] elapsed time: 00:00:00.453
2021-08-16 08:51:11.065 [M: 261M, 0B,D: 0B] [DC: 971, 0] data loaded from storage: 0B, 0s, 0 DC.
2021-08-16 08:51:11.065 [M: 261M, 0B,D: 0B] [DC: 971, 0] data decompressed: 0B, 0s.
2021-08-16 08:51:11.065 [M: 261M, 0B,D: 0B] [DC: 971, 0] temp space IO stats:
2021-08-16 08:51:11.065 [M: 261M, 0B,D: 0B] [DC: 971, 0] CB write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 08:51:11.065 [M: 261M, 0B,D: 0B] [DC: 971, 0] SRT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 08:51:11.065 [M: 261M, 0B,D: 0B] [DC: 971, 0] GDC write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 08:51:11.065 [M: 261M, 0B,D: 0B] [DC: 971, 0] MAT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 08:51:11.065 [M: 261M, 0B,D: 0B] [DC: 971, 0] HSJ write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 08:51:11.065 [M: 261M, 0B,D: 0B] [DC: 971, 0] ======================================================有索引查询id
带索引查询，基本在0.02秒。比无索引的快了10倍。
gbase> select count(*) from tt1 where id=10;
+----------+
| count(*) |
+----------+
| 3717 |
+----------+
1 row in set (Elapsed: 00:00:00.02)
gbase> select count(*) from tt1 where id=1000;
+----------+
| count(*) |
+----------+
| 4402 |
+----------+
1 row in set (Elapsed: 00:00:00.02)
查看trc， 可以看到采用了global hash索引扫描，而不是dc扫描
2021-08-16 14:58:11.969 [M: 3M, 0B,D: 0B] [DC: 0, 0] Global hash index is used:完整trc
2021-08-16 14:54:35.423 [M: 0B, 0B,D: 0B] [DC: 0, 0] SQL Statement:
SELECT COUNT(1) FROM `testdb`.`tt1_n1` `vcname000001.testdb.tt1` WHERE (`vcname000001.testdb.tt1`.`id` = 10)
2021-08-16 14:54:35.423 [M: 0B, 0B,D: 0B] [DC: 0, 0] Start Query Execution
2021-08-16 14:54:35.424 [M: 0B, 0B,D: 0B] [DC: 0, 0] Tables:
2021-08-16 14:54:35.424 [M: 0B, 0B,D: 0B] [DC: 0, 0] T0: vcname000001.testdb.tt1(testdb.tt1_n1), 63567786 rows, 970 DC
2021-08-16 14:54:35.424 [M: 0B, 0B,D: 0B] [DC: 0, 0] Condition Weight (non-join):
2021-08-16 14:54:35.424 [M: 0B, 0B,D: 0B] [DC: 0, 0] cnd(0): vcname000001.testdb.tt1.id BET. 10 AND 10 (0)
2021-08-16 14:54:35.424 [M: 0B, 0B,D: 0B] [DC: 0, 0] BEGIN Smart Scan
2021-08-16 14:54:35.424 [M: 0B, 0B,D: 0B] [DC: 0, 0] T0: total 970 DC, found 970 DC to scan(with 0 FULL DC).
2021-08-16 14:54:35.424 [M: 0B, 0B,D: 0B] [DC: 0, 0] END Smart Scan. (time used: 0.000s)
2021-08-16 14:54:35.424 [M: 0B, 0B,D: 0B] [DC: 0, 0] BEGIN Scan
2021-08-16 14:54:35.424 [M: 0B, 0B,D: 0B] [DC: 0, 0] cnd(0) vcname000001.testdb.tt1.id BET. 10 AND 10
2021-08-16 14:54:35.433 [M: 0B, 64B,D: 0B] [DC: 0, 0] Global hash index is used:
2021-08-16 14:54:35.433 [M: 516K, 64B,D: 0B] [DC: 0, 0] cnd(0) scanned 1867 rows, found 1867 rows (time used: 0.000s)
2021-08-16 14:54:35.433 [M: 516K, 32B,D: 0B] [DC: 0, 0] T0: total 970 DC, found 828 DC after scan(with 0 FULL DC).
2021-08-16 14:54:35.433 [M: 516K, 32B,D: 0B] [DC: 0, 0] END Scan. (time used: 0.010s)
2021-08-16 14:54:35.434 [M: 0B, 0B,D: 0B] [DC: 0, 0] Condition Weight (join):
2021-08-16 14:54:35.434 [M: 0B, 0B,D: 0B] [DC: 0, 0] BEGIN Join
2021-08-16 14:54:35.434 [M: 0B, 0B,D: 0B] [DC: 0, 0] END Join(time used: 0.000s)
2021-08-16 14:54:35.434 [M: 0B, 0B,D: 0B] [DC: 0, 0] BEGIN Scan(after join)
2021-08-16 14:54:35.434 [M: 0B, 0B,D: 0B] [DC: 0, 0] END Scan(after join)(time used: 0.000s)
2021-08-16 14:54:35.434 [M: 0B, 0B,D: 0B] [DC: 0, 0] BEGIN Serial Aggregation(1867 rows)
2021-08-16 14:54:35.434 [M: 0B, 32B,D: 0B] [DC: 0, 0] BEGIN Aggregation(1867 rows)
2021-08-16 14:54:35.434 [M: 0B, 64B,D: 0B] [DC: 0, 0] TempTable::MultiDimensionalGroupByScan(): aggregate 1867 rows)
2021-08-16 14:54:35.435 [M: 516K, 32B,D: 0B] [DC: 0, 0] END Serial Aggregation. (time used: 0.001s)
2021-08-16 14:54:35.435 [M: 516K, 0B,D: 0B] [DC: 1, 0] Send 1 rows already
2021-08-16 14:54:35.435 [M: 0B, 0B,D: 0B] [DC: 1, 0] ResultSender: send 0 rows.
2021-08-16 14:54:35.435 [M: 0B, 0B,D: 0B] [DC: 1, 0] output result done.
2021-08-16 14:54:35.436 [M: 0B, 0B,D: 0B] [DC: 1, 0] SUMMARY
2021-08-16 14:54:35.436 [M: 0B, 0B,D: 0B] [DC: 1, 0] elapsed time: 00:00:00.013
2021-08-16 14:54:35.436 [M: 0B, 0B,D: 0B] [DC: 1, 0] data loaded from storage: 0B, 0s, 0 DC.
2021-08-16 14:54:35.436 [M: 0B, 0B,D: 0B] [DC: 1, 0] data decompressed: 0B, 0s.
2021-08-16 14:54:35.436 [M: 0B, 0B,D: 0B] [DC: 1, 0] temp space IO stats:
2021-08-16 14:54:35.436 [M: 0B, 0B,D: 0B] [DC: 1, 0] CB write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 14:54:35.436 [M: 0B, 0B,D: 0B] [DC: 1, 0] SRT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 14:54:35.436 [M: 0B, 0B,D: 0B] [DC: 1, 0] GDC write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 14:54:35.436 [M: 0B, 0B,D: 0B] [DC: 1, 0] MAT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 14:54:35.436 [M: 0B, 0B,D: 0B] [DC: 1, 0] HSJ write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 14:54:35.436 [M: 0B, 0B,D: 0B] [DC: 1, 0] ======================================================
2021-08-16 14:55:26.397 [M: 0B, 0B,D: 0B] [DC: 0, 0] SQL Statement:
SELECT COUNT(1) FROM `testdb`.`tt1_n1` `vcname000001.testdb.tt1` WHERE (`vcname000001.testdb.tt1`.`id` = 1000)
2021-08-16 14:55:26.397 [M: 0B, 0B,D: 0B] [DC: 0, 0] Start Query Execution
2021-08-16 14:55:26.397 [M: 0B, 0B,D: 0B] [DC: 0, 0] Tables:
2021-08-16 14:55:26.397 [M: 0B, 0B,D: 0B] [DC: 0, 0] T0: vcname000001.testdb.tt1(testdb.tt1_n1), 63567786 rows, 970 DC
2021-08-16 14:55:26.397 [M: 0B, 0B,D: 0B] [DC: 0, 0] Condition Weight (non-join):
2021-08-16 14:55:26.397 [M: 0B, 0B,D: 0B] [DC: 0, 0] cnd(0): vcname000001.testdb.tt1.id BET. 1000 AND 1000 (0)
2021-08-16 14:55:26.397 [M: 0B, 0B,D: 0B] [DC: 0, 0] BEGIN Smart Scan
2021-08-16 14:55:26.397 [M: 0B, 0B,D: 0B] [DC: 0, 0] T0: total 970 DC, found 970 DC to scan(with 0 FULL DC).
2021-08-16 14:55:26.397 [M: 0B, 0B,D: 0B] [DC: 0, 0] END Smart Scan. (time used: 0.000s)
2021-08-16 14:55:26.397 [M: 0B, 0B,D: 0B] [DC: 0, 0] BEGIN Scan
2021-08-16 14:55:26.397 [M: 0B, 0B,D: 0B] [DC: 0, 0] cnd(0) vcname000001.testdb.tt1.id BET. 1000 AND 1000
2021-08-16 14:55:26.404 [M: 0B, 0B,D: 0B] [DC: 0, 0] Global hash index is used:
2021-08-16 14:55:26.404 [M: 0B, 0B,D: 0B] [DC: 0, 0] cnd(0) scanned 2180 rows, found 2180 rows (time used: 0.000s)
2021-08-16 14:55:26.405 [M: 0B, 0B,D: 0B] [DC: 0, 0] T0: total 970 DC, found 882 DC after scan(with 0 FULL DC).
2021-08-16 14:55:26.405 [M: 0B, 0B,D: 0B] [DC: 0, 0] END Scan. (time used: 0.007s)
2021-08-16 14:55:26.405 [M: 0B, 0B,D: 0B] [DC: 0, 0] Condition Weight (join):
2021-08-16 14:55:26.405 [M: 0B, 0B,D: 0B] [DC: 0, 0] BEGIN Join
2021-08-16 14:55:26.405 [M: 0B, 0B,D: 0B] [DC: 0, 0] END Join(time used: 0.000s)
2021-08-16 14:55:26.405 [M: 0B, 0B,D: 0B] [DC: 0, 0] BEGIN Scan(after join)
2021-08-16 14:55:26.405 [M: 0B, 0B,D: 0B] [DC: 0, 0] END Scan(after join)(time used: 0.000s)
2021-08-16 14:55:26.405 [M: 0B, 0B,D: 0B] [DC: 0, 0] BEGIN Serial Aggregation(2180 rows)
2021-08-16 14:55:26.405 [M: 0B, 32B,D: 0B] [DC: 0, 0] BEGIN Aggregation(2180 rows)
2021-08-16 14:55:26.405 [M: 0B, 64B,D: 0B] [DC: 0, 0] TempTable::MultiDimensionalGroupByScan(): aggregate 2180 rows)
2021-08-16 14:55:26.405 [M: 516K, 32B,D: 0B] [DC: 0, 0] END Serial Aggregation. (time used: 0.000s)
2021-08-16 14:55:26.405 [M: 516K, 0B,D: 0B] [DC: 1, 0] Send 1 rows already
2021-08-16 14:55:26.405 [M: 0B, 0B,D: 0B] [DC: 1, 0] ResultSender: send 0 rows.
2021-08-16 14:55:26.405 [M: 0B, 0B,D: 0B] [DC: 1, 0] output result done.
2021-08-16 14:55:26.406 [M: 0B, 0B,D: 0B] [DC: 1, 0] SUMMARY
2021-08-16 14:55:26.406 [M: 0B, 0B,D: 0B] [DC: 1, 0] elapsed time: 00:00:00.009
2021-08-16 14:55:26.406 [M: 0B, 0B,D: 0B] [DC: 1, 0] data loaded from storage: 0B, 0s, 0 DC.
2021-08-16 14:55:26.406 [M: 0B, 0B,D: 0B] [DC: 1, 0] data decompressed: 0B, 0s.
2021-08-16 14:55:26.406 [M: 0B, 0B,D: 0B] [DC: 1, 0] temp space IO stats:
2021-08-16 14:55:26.406 [M: 0B, 0B,D: 0B] [DC: 1, 0] CB write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 14:55:26.406 [M: 0B, 0B,D: 0B] [DC: 1, 0] SRT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 14:55:26.406 [M: 0B, 0B,D: 0B] [DC: 1, 0] GDC write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 14:55:26.406 [M: 0B, 0B,D: 0B] [DC: 1, 0] MAT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 14:55:26.406 [M: 0B, 0B,D: 0B] [DC: 1, 0] HSJ write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 14:55:26.406 [M: 0B, 0B,D: 0B] [DC: 1, 0] ======================================================
无索引name列测试
结果集15行，基本在6秒以上。重复执行，因为内存不足，还是要从磁盘读取数据。
gbase> select count(*) from tt1 where name='7ce4c628-3c8b-495f-b44c-ed4fefc97f59';
+----------+
| count(*) |
+----------+
| 15 |
+----------+
1 row in set (Elapsed: 00:00:10.65)
gbase> select count(*) from tt1 where name='7ce4c628-3c8b-495f-b44c-ed4fefc97f59';
+----------+
| count(*) |
+----------+
| 15 |
+----------+
1 row in set (Elapsed: 00:00:06.59)
gbase> select count(*) from tt1 where name='83812e39-5336-4b3f-b376-50dd485de980';
+----------+
| count(*) |
+----------+
| 15 |
+----------+
1 row in set (Elapsed: 00:00:06.89)
gbase> select count(*) from tt1 where name='83812e39-5336-4b3f-b376-50dd485de980';
+----------+
| count(*) |
+----------+
| 15 |
+----------+
1 row in set (Elapsed: 00:00:06.47)trc日志
2021-08-16 15:38:40.299 [M: 0B, 0B,D: 0B] [DC: 0, 0] SQL Statement:
SELECT COUNT(1) FROM `testdb`.`tt1_n2` `vcname000001.testdb.tt1` WHERE (`vcname000001.testdb.tt1`.`name` = '7ce4c628-3c8b-495f-b44c-ed4fefc97f59')
2021-08-16 15:38:40.299 [M: 0B, 0B,D: 0B] [DC: 0, 0] Start Query Execution
2021-08-16 15:38:40.299 [M: 0B, 0B,D: 0B] [DC: 0, 0] Tables:
2021-08-16 15:38:40.299 [M: 0B, 0B,D: 0B] [DC: 0, 0] T0: vcname000001.testdb.tt1(testdb.tt1_n2), 63567723 rows, 970 DC
2021-08-16 15:38:40.299 [M: 0B, 0B,D: 0B] [DC: 0, 0] Condition Weight (non-join):
2021-08-16 15:38:40.299 [M: 0B, 0B,D: 0B] [DC: 0, 0] cnd(0): vcname000001.testdb.tt1.name BET. '7ce4c628-3c8b-495f-b44c-ed4fefc97f59' AND '7ce4c628-3c8b-495f-b44c-ed4fefc97f59' (0)
2021-08-16 15:38:40.299 [M: 0B, 0B,D: 0B] [DC: 0, 0] BEGIN Smart Scan
2021-08-16 15:38:40.301 [M: 0B, 0B,D: 0B] [DC: 0, 0] T0: total 970 DC, found 970 DC to scan(with 0 FULL DC).
2021-08-16 15:38:40.301 [M: 0B, 0B,D: 0B] [DC: 0, 0] END Smart Scan. (time used: 0.001s)
2021-08-16 15:38:40.301 [M: 0B, 0B,D: 0B] [DC: 0, 0] BEGIN Scan
2021-08-16 15:38:40.301 [M: 0B, 0B,D: 0B] [DC: 0, 0] cnd(0) vcname000001.testdb.tt1.name BET. '7ce4c628-3c8b-495f-b44c-ed4fefc97f59' AND '7ce4c628-3c8b-495f-b44c-ed4fefc97f59'
2021-08-16 15:38:50.372 [M:2.48G, 0B,D: 0B] [DC: 2, 937] ( 2)cnd(0) scanned 15925248 rows, found 1 rows (time used: 10.072s)
2021-08-16 15:38:50.621 [M:2.61G, 0B,D: 0B] [DC: 2, 958] ( 0)cnd(0) scanned 15925248 rows, found 1 rows (time used: 10.320s)
2021-08-16 15:38:50.735 [M:2.65G, 0B,D: 0B] [DC: 0, 964] ( 3)cnd(0) scanned 15857515 rows, found 0 rows (time used: 10.435s)
2021-08-16 15:38:50.842 [M:2.70G, 0B,D: 0B] [DC: 0, 970] ( 1)cnd(0) scanned 15859712 rows, found 2 rows (time used: 10.541s)
2021-08-16 15:38:50.842 [M:2.70G, 0B,D: 0B] [DC: 0, 970] cnd(0) Done. scanned 63567723 rows, found 4 rows (time used: 10.542s)
2021-08-16 15:38:50.843 [M:2.70G, 0B,D: 0B] [DC: 0, 970] T0: total 970 DC, found 4 DC after scan(with 0 FULL DC).
2021-08-16 15:38:50.843 [M:2.70G, 0B,D: 0B] [DC: 0, 970] END Scan. (time used: 10.542s)
2021-08-16 15:38:50.843 [M:2.70G, 0B,D: 0B] [DC: 0, 970] Condition Weight (join):
2021-08-16 15:38:50.843 [M:2.70G, 0B,D: 0B] [DC: 0, 970] BEGIN Join
2021-08-16 15:38:50.843 [M:2.70G, 0B,D: 0B] [DC: 0, 970] END Join(time used: 0.000s)
2021-08-16 15:38:50.843 [M:2.70G, 0B,D: 0B] [DC: 0, 970] BEGIN Scan(after join)
2021-08-16 15:38:50.843 [M:2.70G, 0B,D: 0B] [DC: 0, 970] END Scan(after join)(time used: 0.000s)
2021-08-16 15:38:50.843 [M:2.70G, 0B,D: 0B] [DC: 0, 970] BEGIN Serial Aggregation(4 rows)
2021-08-16 15:38:50.843 [M:2.70G, 32B,D: 0B] [DC: 0, 970] BEGIN Aggregation(4 rows)
2021-08-16 15:38:50.843 [M:2.70G, 64B,D: 0B] [DC: 0, 970] TempTable::MultiDimensionalGroupByScan(): aggregate 4 rows)
2021-08-16 15:38:50.843 [M:2.70G, 32B,D: 0B] [DC: 0, 970] END Serial Aggregation. (time used: 0.000s)
2021-08-16 15:38:50.843 [M:2.70G, 0B,D: 0B] [DC: 1, 970] Send 1 rows already
2021-08-16 15:38:50.877 [M:2.71G, 0B,D: 0B] [DC: 1, 970] ResultSender: send 0 rows.
2021-08-16 15:38:50.877 [M:2.71G, 0B,D: 0B] [DC: 1, 970] output result done.
2021-08-16 15:38:50.877 [M:2.71G, 0B,D: 0B] [DC: 1, 970] SUMMARY
2021-08-16 15:38:50.877 [M:2.71G, 0B,D: 0B] [DC: 1, 970] elapsed time: 00:00:10.578
2021-08-16 15:38:50.877 [M:2.71G, 0B,D: 0B] [DC: 1, 970] data loaded from storage: 2.02G, 28.915s, 970 DC.
2021-08-16 15:38:50.877 [M:2.71G, 0B,D: 0B] [DC: 1, 970] data decompressed: 2.72G, 4.281s.
2021-08-16 15:38:50.877 [M:2.71G, 0B,D: 0B] [DC: 1, 970] temp space IO stats:
2021-08-16 15:38:50.877 [M:2.71G, 0B,D: 0B] [DC: 1, 970] CB write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:38:50.877 [M:2.71G, 0B,D: 0B] [DC: 1, 970] SRT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:38:50.877 [M:2.71G, 0B,D: 0B] [DC: 1, 970] GDC write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:38:50.878 [M:2.71G, 0B,D: 0B] [DC: 1, 970] MAT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:38:50.878 [M:2.71G, 0B,D: 0B] [DC: 1, 970] HSJ write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:38:50.878 [M:2.71G, 0B,D: 0B] [DC: 1, 970] ======================================================
2021-08-16 15:38:55.867 [M:2.72G, 0B,D: 0B] [DC: 0, 0] SQL Statement:
SELECT COUNT(1) FROM `testdb`.`tt1_n2` `vcname000001.testdb.tt1` WHERE (`vcname000001.testdb.tt1`.`name` = '7ce4c628-3c8b-495f-b44c-ed4fefc97f59')
2021-08-16 15:38:55.867 [M:2.72G, 0B,D: 0B] [DC: 0, 0] Start Query Execution
2021-08-16 15:38:55.868 [M:2.72G, 0B,D: 0B] [DC: 0, 0] Tables:
2021-08-16 15:38:55.868 [M:2.72G, 0B,D: 0B] [DC: 0, 0] T0: vcname000001.testdb.tt1(testdb.tt1_n2), 63567723 rows, 970 DC
2021-08-16 15:38:55.868 [M:2.72G, 0B,D: 0B] [DC: 0, 0] Condition Weight (non-join):
2021-08-16 15:38:55.868 [M:2.72G, 0B,D: 0B] [DC: 0, 0] cnd(0): vcname000001.testdb.tt1.name BET. '7ce4c628-3c8b-495f-b44c-ed4fefc97f59' AND '7ce4c628-3c8b-495f-b44c-ed4fefc97f59' (0)
2021-08-16 15:38:55.868 [M:2.72G, 0B,D: 0B] [DC: 0, 0] BEGIN Smart Scan
2021-08-16 15:38:55.869 [M:2.72G, 0B,D: 0B] [DC: 0, 0] T0: total 970 DC, found 970 DC to scan(with 0 FULL DC).
2021-08-16 15:38:55.869 [M:2.72G, 0B,D: 0B] [DC: 0, 0] END Smart Scan. (time used: 0.001s)
2021-08-16 15:38:55.869 [M:2.72G, 0B,D: 0B] [DC: 0, 0] BEGIN Scan
2021-08-16 15:38:55.869 [M:2.72G, 0B,D: 0B] [DC: 0, 0] cnd(0) vcname000001.testdb.tt1.name BET. '7ce4c628-3c8b-495f-b44c-ed4fefc97f59' AND '7ce4c628-3c8b-495f-b44c-ed4fefc97f59'
2021-08-16 15:39:01.755 [M:2.03G, 0B,D: 0B] [DC: 255, 646] ( 2)cnd(0) scanned 15925248 rows, found 1 rows (time used: 5.885s)
2021-08-16 15:39:02.170 [M:2.33G, 0B,D: 0B] [DC: 254, 696] ( 1)cnd(0) scanned 15859712 rows, found 2 rows (time used: 6.301s)
2021-08-16 15:39:02.314 [M:2.42G, 0B,D: 0B] [DC: 254, 710] ( 0)cnd(0) scanned 15925248 rows, found 1 rows (time used: 6.445s)
2021-08-16 15:39:02.406 [M:2.47G, 0B,D: 0B] [DC: 254, 716] ( 3)cnd(0) scanned 15857515 rows, found 0 rows (time used: 6.514s)
2021-08-16 15:39:02.406 [M:2.47G, 0B,D: 0B] [DC: 254, 716] cnd(0) Done. scanned 63567723 rows, found 4 rows (time used: 6.537s)
2021-08-16 15:39:02.406 [M:2.47G, 0B,D: 0B] [DC: 254, 716] T0: total 970 DC, found 4 DC after scan(with 0 FULL DC).
2021-08-16 15:39:02.406 [M:2.47G, 0B,D: 0B] [DC: 254, 716] END Scan. (time used: 6.537s)
2021-08-16 15:39:02.406 [M:2.47G, 0B,D: 0B] [DC: 254, 716] Condition Weight (join):
2021-08-16 15:39:02.406 [M:2.47G, 0B,D: 0B] [DC: 254, 716] BEGIN Join
2021-08-16 15:39:02.406 [M:2.47G, 0B,D: 0B] [DC: 254, 716] END Join(time used: 0.000s)
2021-08-16 15:39:02.406 [M:2.47G, 0B,D: 0B] [DC: 254, 716] BEGIN Scan(after join)
2021-08-16 15:39:02.406 [M:2.47G, 0B,D: 0B] [DC: 254, 716] END Scan(after join)(time used: 0.000s)
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 254, 716] BEGIN Serial Aggregation(4 rows)
2021-08-16 15:39:02.407 [M:2.47G, 32B,D: 0B] [DC: 254, 716] BEGIN Aggregation(4 rows)
2021-08-16 15:39:02.407 [M:2.47G, 64B,D: 0B] [DC: 254, 716] TempTable::MultiDimensionalGroupByScan(): aggregate 4 rows)
2021-08-16 15:39:02.407 [M:2.47G, 32B,D: 0B] [DC: 254, 716] END Serial Aggregation. (time used: 0.000s)
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 255, 716] Send 1 rows already
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 255, 716] ResultSender: send 0 rows.
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 255, 716] output result done.
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 255, 716] SUMMARY
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 255, 716] elapsed time: 00:00:06.539
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 255, 716] data loaded from storage: 1.49G, 3.12s, 716 DC.
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 255, 716] data decompressed: 2.01G, 6.736s.
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 255, 716] temp space IO stats:
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 255, 716] CB write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 255, 716] SRT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 255, 716] GDC write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 255, 716] MAT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 255, 716] HSJ write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 255, 716] ======================================================
2021-08-16 15:39:02.407 [M:2.47G, 0B,D: 0B] [DC: 255, 716] ======================================================
2021-08-16 15:39:45.569 [M:2.48G, 0B,D: 0B] [DC: 0, 0] SQL Statement:
SELECT COUNT(1) FROM `testdb`.`tt1_n2` `vcname000001.testdb.tt1` WHERE (`vcname000001.testdb.tt1`.`name` = '83812e39-5336-4b3f-b376-50dd485de980')
2021-08-16 15:39:45.569 [M:2.48G, 0B,D: 0B] [DC: 0, 0] Start Query Execution
2021-08-16 15:39:45.569 [M:2.48G, 0B,D: 0B] [DC: 0, 0] Tables:
2021-08-16 15:39:45.569 [M:2.48G, 0B,D: 0B] [DC: 0, 0] T0: vcname000001.testdb.tt1(testdb.tt1_n2), 63567723 rows, 970 DC
2021-08-16 15:39:45.569 [M:2.48G, 0B,D: 0B] [DC: 0, 0] Condition Weight (non-join):
2021-08-16 15:39:45.569 [M:2.48G, 0B,D: 0B] [DC: 0, 0] cnd(0): vcname000001.testdb.tt1.name BET. '83812e39-5336-4b3f-b376-50dd485de980' AND '83812e39-5336-4b3f-b376-50dd485de980' (0)
2021-08-16 15:39:45.569 [M:2.48G, 0B,D: 0B] [DC: 0, 0] BEGIN Smart Scan
2021-08-16 15:39:45.571 [M:2.48G, 0B,D: 0B] [DC: 0, 0] T0: total 970 DC, found 970 DC to scan(with 0 FULL DC).
2021-08-16 15:39:45.571 [M:2.48G, 0B,D: 0B] [DC: 0, 0] END Smart Scan. (time used: 0.001s)
2021-08-16 15:39:45.571 [M:2.48G, 0B,D: 0B] [DC: 0, 0] BEGIN Scan
2021-08-16 15:39:45.571 [M:2.48G, 0B,D: 0B] [DC: 0, 0] cnd(0) vcname000001.testdb.tt1.name BET. '83812e39-5336-4b3f-b376-50dd485de980' AND '83812e39-5336-4b3f-b376-50dd485de980'
^[[B2021-08-16 15:39:51.726 [M:2.00G, 0B,D: 0B] [DC: 254, 690] ( 3)cnd(0) scanned 15857515 rows, found 1 rows (time used: 6.146s)
2021-08-16 15:39:51.887 [M:2.12G, 0B,D: 0B] [DC: 253, 710] ( 1)cnd(0) scanned 15859712 rows, found 2 rows (time used: 6.317s)
2021-08-16 15:39:51.896 [M:2.12G, 0B,D: 0B] [DC: 252, 712] ( 2)cnd(0) scanned 15925248 rows, found 2 rows (time used: 6.315s)
2021-08-16 15:39:51.989 [M:2.18G, 0B,D: 0B] [DC: 252, 718] ( 0)cnd(0) scanned 15925248 rows, found 1 rows (time used: 6.397s)
2021-08-16 15:39:51.991 [M:2.18G, 0B,D: 0B] [DC: 252, 718] cnd(0) Done. scanned 63567723 rows, found 6 rows (time used: 6.420s)
2021-08-16 15:39:51.994 [M:2.18G, 0B,D: 0B] [DC: 252, 718] T0: total 970 DC, found 6 DC after scan(with 0 FULL DC).
2021-08-16 15:39:51.994 [M:2.18G, 0B,D: 0B] [DC: 252, 718] END Scan. (time used: 6.423s)
2021-08-16 15:39:51.994 [M:2.18G, 0B,D: 0B] [DC: 252, 718] Condition Weight (join):
2021-08-16 15:39:51.994 [M:2.18G, 0B,D: 0B] [DC: 252, 718] BEGIN Join
2021-08-16 15:39:51.994 [M:2.18G, 0B,D: 0B] [DC: 252, 718] END Join(time used: 0.000s)
2021-08-16 15:39:51.994 [M:2.18G, 0B,D: 0B] [DC: 252, 718] BEGIN Scan(after join)
2021-08-16 15:39:51.994 [M:2.18G, 0B,D: 0B] [DC: 252, 718] END Scan(after join)(time used: 0.000s)
2021-08-16 15:39:51.994 [M:2.18G, 0B,D: 0B] [DC: 252, 718] BEGIN Serial Aggregation(6 rows)
2021-08-16 15:39:51.994 [M:2.18G, 32B,D: 0B] [DC: 252, 718] BEGIN Aggregation(6 rows)
2021-08-16 15:39:51.994 [M:2.18G, 64B,D: 0B] [DC: 252, 718] TempTable::MultiDimensionalGroupByScan(): aggregate 6 rows)
2021-08-16 15:39:51.994 [M:2.18G, 32B,D: 0B] [DC: 252, 718] END Serial Aggregation. (time used: 0.000s)
2021-08-16 15:39:51.994 [M:2.18G, 0B,D: 0B] [DC: 253, 718] Send 1 rows already
2021-08-16 15:39:51.995 [M:2.18G, 0B,D: 0B] [DC: 253, 718] ResultSender: send 0 rows.
2021-08-16 15:39:51.995 [M:2.18G, 0B,D: 0B] [DC: 253, 718] output result done.
2021-08-16 15:39:51.995 [M:2.18G, 0B,D: 0B] [DC: 253, 718] SUMMARY
2021-08-16 15:39:51.995 [M:2.18G, 0B,D: 0B] [DC: 253, 718] elapsed time: 00:00:06.425
2021-08-16 15:39:51.995 [M:2.18G, 0B,D: 0B] [DC: 253, 718] data loaded from storage: 1.50G, 2.549s, 718 DC.
2021-08-16 15:39:51.995 [M:2.18G, 0B,D: 0B] [DC: 253, 718] data decompressed: 2.02G, 6.868s.
2021-08-16 15:39:51.995 [M:2.18G, 0B,D: 0B] [DC: 253, 718] temp space IO stats:
2021-08-16 15:39:51.995 [M:2.18G, 0B,D: 0B] [DC: 253, 718] CB write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:39:51.995 [M:2.18G, 0B,D: 0B] [DC: 253, 718] SRT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:39:51.995 [M:2.18G, 0B,D: 0B] [DC: 253, 718] GDC write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:39:51.995 [M:2.18G, 0B,D: 0B] [DC: 253, 718] MAT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:39:51.995 [M:2.18G, 0B,D: 0B] [DC: 253, 718] HSJ write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:39:51.995 [M:2.18G, 0B,D: 0B] [DC: 253, 718] ======================================================
2021-08-16 15:39:56.093 [M:2.33G, 0B,D: 0B] [DC: 0, 0] SQL Statement:
SELECT COUNT(1) FROM `testdb`.`tt1_n2` `vcname000001.testdb.tt1` WHERE (`vcname000001.testdb.tt1`.`name` = '83812e39-5336-4b3f-b376-50dd485de980')
2021-08-16 15:39:56.093 [M:2.33G, 0B,D: 0B] [DC: 0, 0] Start Query Execution
2021-08-16 15:39:56.093 [M:2.33G, 0B,D: 0B] [DC: 0, 0] Tables:
2021-08-16 15:39:56.093 [M:2.33G, 0B,D: 0B] [DC: 0, 0] T0: vcname000001.testdb.tt1(testdb.tt1_n2), 63567723 rows, 970 DC
2021-08-16 15:39:56.093 [M:2.33G, 0B,D: 0B] [DC: 0, 0] Condition Weight (non-join):
2021-08-16 15:39:56.093 [M:2.33G, 0B,D: 0B] [DC: 0, 0] cnd(0): vcname000001.testdb.tt1.name BET. '83812e39-5336-4b3f-b376-50dd485de980' AND '83812e39-5336-4b3f-b376-50dd485de980' (0)
2021-08-16 15:39:56.094 [M:2.33G, 0B,D: 0B] [DC: 0, 0] BEGIN Smart Scan
2021-08-16 15:39:56.095 [M:2.33G, 0B,D: 0B] [DC: 0, 0] T0: total 970 DC, found 970 DC to scan(with 0 FULL DC).
2021-08-16 15:39:56.095 [M:2.33G, 0B,D: 0B] [DC: 0, 0] END Smart Scan. (time used: 0.001s)
2021-08-16 15:39:56.095 [M:2.33G, 0B,D: 0B] [DC: 0, 0] BEGIN Scan
2021-08-16 15:39:56.095 [M:2.33G, 0B,D: 0B] [DC: 0, 0] cnd(0) vcname000001.testdb.tt1.name BET. '83812e39-5336-4b3f-b376-50dd485de980' AND '83812e39-5336-4b3f-b376-50dd485de980'
2021-08-16 15:40:02.225 [M:2.11G, 0B,D: 0B] [DC: 252, 701] ( 2)cnd(0) scanned 15925248 rows, found 2 rows (time used: 6.107s)
2021-08-16 15:40:02.351 [M:2.19G, 0B,D: 0B] [DC: 253, 712] ( 0)cnd(0) scanned 15925248 rows, found 1 rows (time used: 6.256s)
2021-08-16 15:40:02.404 [M:2.23G, 0B,D: 0B] [DC: 252, 718] ( 1)cnd(0) scanned 15859712 rows, found 2 rows (time used: 6.309s)
2021-08-16 15:40:02.410 [M:2.22G, 0B,D: 0B] [DC: 252, 718] ( 3)cnd(0) scanned 15857515 rows, found 1 rows (time used: 6.315s)
2021-08-16 15:40:02.411 [M:2.22G, 0B,D: 0B] [DC: 252, 718] cnd(0) Done. scanned 63567723 rows, found 6 rows (time used: 6.316s)
2021-08-16 15:40:02.411 [M:2.22G, 0B,D: 0B] [DC: 252, 718] T0: total 970 DC, found 6 DC after scan(with 0 FULL DC).
2021-08-16 15:40:02.411 [M:2.22G, 0B,D: 0B] [DC: 252, 718] END Scan. (time used: 6.316s)
2021-08-16 15:40:02.411 [M:2.22G, 0B,D: 0B] [DC: 252, 718] Condition Weight (join):
2021-08-16 15:40:02.411 [M:2.22G, 0B,D: 0B] [DC: 252, 718] BEGIN Join
2021-08-16 15:40:02.411 [M:2.22G, 0B,D: 0B] [DC: 252, 718] END Join(time used: 0.000s)
2021-08-16 15:40:02.411 [M:2.22G, 0B,D: 0B] [DC: 252, 718] BEGIN Scan(after join)
2021-08-16 15:40:02.411 [M:2.22G, 0B,D: 0B] [DC: 252, 718] END Scan(after join)(time used: 0.000s)
2021-08-16 15:40:02.411 [M:2.22G, 0B,D: 0B] [DC: 252, 718] BEGIN Serial Aggregation(6 rows)
2021-08-16 15:40:02.411 [M:2.22G, 32B,D: 0B] [DC: 252, 718] BEGIN Aggregation(6 rows)
2021-08-16 15:40:02.411 [M:2.22G, 64B,D: 0B] [DC: 252, 718] TempTable::MultiDimensionalGroupByScan(): aggregate 6 rows)
2021-08-16 15:40:02.411 [M:2.22G, 32B,D: 0B] [DC: 252, 718] END Serial Aggregation. (time used: 0.000s)
2021-08-16 15:40:02.412 [M:2.22G, 0B,D: 0B] [DC: 253, 718] Send 1 rows already
2021-08-16 15:40:02.412 [M:2.22G, 0B,D: 0B] [DC: 253, 718] ResultSender: send 0 rows.
2021-08-16 15:40:02.412 [M:2.22G, 0B,D: 0B] [DC: 253, 718] output result done.
2021-08-16 15:40:02.412 [M:2.22G, 0B,D: 0B] [DC: 253, 718] SUMMARY
2021-08-16 15:40:02.412 [M:2.22G, 0B,D: 0B] [DC: 253, 718] elapsed time: 00:00:06.318
2021-08-16 15:40:02.412 [M:2.22G, 0B,D: 0B] [DC: 253, 718] data loaded from storage: 1.50G, 2.679s, 718 DC.
2021-08-16 15:40:02.412 [M:2.22G, 0B,D: 0B] [DC: 253, 718] data decompressed: 2.02G, 6.304s.
2021-08-16 15:40:02.412 [M:2.22G, 0B,D: 0B] [DC: 253, 718] temp space IO stats:
2021-08-16 15:40:02.412 [M:2.22G, 0B,D: 0B] [DC: 253, 718] CB write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:40:02.412 [M:2.22G, 0B,D: 0B] [DC: 253, 718] SRT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:40:02.412 [M:2.22G, 0B,D: 0B] [DC: 253, 718] GDC write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:40:02.412 [M:2.22G, 0B,D: 0B] [DC: 253, 718] MAT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:40:02.412 [M:2.22G, 0B,D: 0B] [DC: 253, 718] HSJ write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:40:02.412 [M:2.22G, 0B,D: 0B] [DC: 253, 718] ======================================================有索引name列测试
有索引测试，基本在0.05秒，比无索引快了100倍。
gbase> select count(*) from tt1 where name='7ce4c628-3c8b-495f-b44c-ed4fefc97f59';
+----------+
| count(*) |
+----------+
| 15 |
+----------+
1 row in set (Elapsed: 00:00:00.05)
gbase> select count(*) from tt1 where name='83812e39-5336-4b3f-b376-50dd485de980';
+----------+
| count(*) |
+----------+
| 15 |
+----------+
1 row in set (Elapsed: 00:00:00.04)trace日志
2021-08-16 15:36:26.571 [M:2.65G, 0B,D: 0B] [DC: 0, 0] SQL Statement:
SELECT COUNT(1) FROM `testdb`.`tt1_n2` `vcname000001.testdb.tt1` WHERE (`vcname000001.testdb.tt1`.`name` = '7ce4c628-3c8b-495f-b44c-ed4fefc97f59')
2021-08-16 15:36:26.571 [M:2.65G, 0B,D: 0B] [DC: 0, 0] Start Query Execution
2021-08-16 15:36:26.571 [M:2.65G, 0B,D: 0B] [DC: 0, 0] Tables:
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] T0: vcname000001.testdb.tt1(testdb.tt1_n2), 63567723 rows, 970 DC
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] Condition Weight (non-join):
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] cnd(0): vcname000001.testdb.tt1.name BET. '7ce4c628-3c8b-495f-b44c-ed4fefc97f59' AND '7ce4c628-3c8b-495f-b44c-ed4fefc97f59' (0)
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] BEGIN Smart Scan
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] T0: total 970 DC, found 970 DC to scan(with 0 FULL DC).
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] END Smart Scan. (time used: 0.000s)
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] BEGIN Scan
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] cnd(0) vcname000001.testdb.tt1.name BET. '7ce4c628-3c8b-495f-b44c-ed4fefc97f59' AND '7ce4c628-3c8b-495f-b44c-ed4fefc97f59'
2021-08-16 15:36:26.602 [M:2.65G, 0B,D: 0B] [DC: 0, 0] Global hash index is used:
2021-08-16 15:36:26.602 [M:2.65G, 0B,D: 0B] [DC: 0, 0] cnd(0) scanned 4 rows, found 4 rows (time used: 0.000s)
2021-08-16 15:36:26.602 [M:2.65G, 0B,D: 0B] [DC: 0, 0] T0: total 970 DC, found 4 DC after scan(with 0 FULL DC).
2021-08-16 15:36:26.602 [M:2.65G, 0B,D: 0B] [DC: 0, 0] END Scan. (time used: 0.031s)
2021-08-16 15:36:26.602 [M:2.65G, 0B,D: 0B] [DC: 0, 0] Condition Weight (join):
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 0, 0] BEGIN Join
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 0, 0] END Join(time used: 0.000s)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 0, 0] BEGIN Scan(after join)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 0, 0] END Scan(after join)(time used: 0.000s)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 0, 0] BEGIN Serial Aggregation(4 rows)
2021-08-16 15:36:26.603 [M:2.65G, 32B,D: 0B] [DC: 0, 0] BEGIN Aggregation(4 rows)
2021-08-16 15:36:26.603 [M:2.65G, 64B,D: 0B] [DC: 0, 0] TempTable::MultiDimensionalGroupByScan(): aggregate 4 rows)
2021-08-16 15:36:26.603 [M:2.65G, 32B,D: 0B] [DC: 0, 0] END Serial Aggregation. (time used: 0.000s)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] Send 1 rows already
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] ResultSender: send 0 rows.
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] output result done.
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] SUMMARY
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] elapsed time: 00:00:00.031
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] data loaded from storage: 0B, 0s, 0 DC.
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] data decompressed: 0B, 0s.
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] temp space IO stats:
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] CB write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] SRT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] GDC write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] MAT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] HSJ write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] ======================================================
2021-08-16 15:36:26.571 [M:2.65G, 0B,D: 0B] [DC: 0, 0] SQL Statement:
SELECT COUNT(1) FROM `testdb`.`tt1_n2` `vcname000001.testdb.tt1` WHERE (`vcname000001.testdb.tt1`.`name` = '7ce4c628-3c8b-495f-b44c-ed4fefc97f59')
2021-08-16 15:36:26.571 [M:2.65G, 0B,D: 0B] [DC: 0, 0] Start Query Execution
2021-08-16 15:36:26.571 [M:2.65G, 0B,D: 0B] [DC: 0, 0] Tables:
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] T0: vcname000001.testdb.tt1(testdb.tt1_n2), 63567723 rows, 970 DC
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] Condition Weight (non-join):
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] cnd(0): vcname000001.testdb.tt1.name BET. '7ce4c628-3c8b-495f-b44c-ed4fefc97f59' AND '7ce4c628-3c8b-495f-b44c-ed4fefc97f59' (0)
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] BEGIN Smart Scan
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] T0: total 970 DC, found 970 DC to scan(with 0 FULL DC).
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] END Smart Scan. (time used: 0.000s)
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] BEGIN Scan
2021-08-16 15:36:26.572 [M:2.65G, 0B,D: 0B] [DC: 0, 0] cnd(0) vcname000001.testdb.tt1.name BET. '7ce4c628-3c8b-495f-b44c-ed4fefc97f59' AND '7ce4c628-3c8b-495f-b44c-ed4fefc97f59'
2021-08-16 15:36:26.602 [M:2.65G, 0B,D: 0B] [DC: 0, 0] Global hash index is used:
2021-08-16 15:36:26.602 [M:2.65G, 0B,D: 0B] [DC: 0, 0] cnd(0) scanned 4 rows, found 4 rows (time used: 0.000s)
2021-08-16 15:36:26.602 [M:2.65G, 0B,D: 0B] [DC: 0, 0] T0: total 970 DC, found 4 DC after scan(with 0 FULL DC).
2021-08-16 15:36:26.602 [M:2.65G, 0B,D: 0B] [DC: 0, 0] END Scan. (time used: 0.031s)
2021-08-16 15:36:26.602 [M:2.65G, 0B,D: 0B] [DC: 0, 0] Condition Weight (join):
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 0, 0] BEGIN Join
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 0, 0] END Join(time used: 0.000s)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 0, 0] BEGIN Scan(after join)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 0, 0] END Scan(after join)(time used: 0.000s)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 0, 0] BEGIN Serial Aggregation(4 rows)
2021-08-16 15:36:26.603 [M:2.65G, 32B,D: 0B] [DC: 0, 0] BEGIN Aggregation(4 rows)
2021-08-16 15:36:26.603 [M:2.65G, 64B,D: 0B] [DC: 0, 0] TempTable::MultiDimensionalGroupByScan(): aggregate 4 rows)
2021-08-16 15:36:26.603 [M:2.65G, 32B,D: 0B] [DC: 0, 0] END Serial Aggregation. (time used: 0.000s)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] Send 1 rows already
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] ResultSender: send 0 rows.
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] output result done.
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] SUMMARY
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] elapsed time: 00:00:00.031
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] data loaded from storage: 0B, 0s, 0 DC.
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] data decompressed: 0B, 0s.
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] temp space IO stats:
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] CB write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] SRT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] GDC write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] MAT write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] HSJ write( 0B, 0time, 0sec), read( 0B, 0time, 0sec)
2021-08-16 15:36:26.603 [M:2.65G, 0B,D: 0B] [DC: 1, 0] ======================================================总结
global hash索引，只适合重复值少的列，比如电话号码，身份证，imsi, msisdn等，不适合重复度高，比如民族，城市等。另外，只针对精确等值查询，对范围查询无效。