复制 [root@EULER1~]# su-pg1-c"psql -Upostgres -p 5432 -h 192.168.123.60"Passwordforuser postgres:psql(12.5)Type"help"forhelp.postgres=# create tablespace mytbs location'/opt/custome-tablespace';CREATETABLESPACEpostgres=# \db+Listoftablespaces Name|Owner|Location|Access privileges|Options|Size|...
Often the best choice will be to partition by the column or set of columns which most commonly appear in WHERE clauses of queries being executed on the partitioned table. WHERE clauses that are compatible with the partition bound constraints can be used to prune unneeded partitions. However, ...
CREATETABLEfoo (fooidint, foosubidint, fooname text);CREATEFUNCTIONgetfoo(int)RETURNSSETOF fooAS$$SELECT*FROMfooWHEREfooid=$1; $$LANGUAGESQL;SELECT*FROMgetfoo(1)ASt1;SELECT*FROMfooWHEREfoosubidIN(SELECTfoosubidFROMgetfoo(foo.fooid) zWHEREz.fooid=foo.fooid );CREATEVIEWvw_getfooASSELECT...
JOIN pg_database pd ON psd.datname = pd.datname WHERE psd.datname not ilike 'template%' AND psd.datname not ilike 'rdsadmin' AND psd.datname not ilike 'azure_maintenance' AND psd.datname not ilike 'postgres' 切割效果: PostgreSQL 采集器完整配置 # {"version": "1.34.0", "desc": "...
list分区表键:支持单个列、或单个表达式 分区键必须有对应的btree索引方法的ops(可以查看系统表得到) selecttypnamefrompg_typewhereoidin(selectopcintypefrompg_opclass); 主表不会有任何数据,数据会根据分区规则进入对应的分区表 如果插入数据时,分区键的值没有匹配的分区,会报错 ...
.update({username:'qaz'});//删除awaitpqorm.model('users').where({user_id:'234'}).delete(); }); @ 标记 value值在构造SQL语句时会自动进行引用处理,比如字符串'a b c'可能会变成$_123_$a b c$_123_$ 如果不想进行自动的引用处理,则需要在key值前加上@标记。
explain select * from part_list where name='fujian'; hash分区表 hash分区将数据散列存储在各个分区上,以打散热点数据存放到对应的分区上,然后把满足条件的行存放在该分区中,最常见的是平均的把数据放在不同的分区。 hash分区实现: 1、创建主表 CREATE TABLE part_hash (order_id int,name varchar(10)) PA...
如果HAVING子句中没有聚集函数的话,那么它完全可以退化到WHERE子句中去,否则的话它将被写到查询树的HavingQual字段里面。 4.2 改进查询树 4.2.1 路径生成 生成路径工作由函数query_planner来完成,整体流程如下: 因为单表有多种访问方式(索引访问,顺序访问等)、表和表直接有着多种连接方式和连接顺序,所以就算基本表...
typedefstructAllocSetContext{MemoryContextData header;/*对应于该内存上下文的头部信息 Standard memory-context fields *//* Info about storage allocated in this context: */AllocBlock blocks;/*该内存上下文中所有内存块的链表 head of list of blocks in this set */AllocChunk freelist[ALLOCSET_NUM_FREEL...
该函数主要用于判断元组的合法性,即元组是否符合where条件 bool ExecQual(List *qual, ExprContext *econtext, bool resultForNull) { bool result; MemoryContext oldContext; ListCell *l; /* * debugging stuff */ EV_printf("ExecQual: qual is "); EV_nodeDisplay(qual); EV_printf("\n"); /* *...