问题: 程序里需要监视某个目录下的文件变化情况: 一旦目录中出现新文件或者旧的文件被覆盖,程序需要读取文件内容并进行处理;但在实际处理中发现当一个文件产生变化时,Change事件被反复触发了好几次。...这样可能的结果是造成同一文件的重复处理。 解决方法: 针对上面的问题,于是写了一个可以延迟FileSystemWatcher发出的...
Your Postgres commands in one place. Learn how to use psql to list and create Postgres databases, show your tables, enter your Postgres terminal, and more.
select nextval('t_a_seq'::regclass); ALTER SEQUENCE name [ INCREMENT [ BY ] increment ] [ MINVALUE minvalue | NO MINVALUE ] [ MAXVALUE maxvalue | NO MAXVALUE ] [ START [ WITH ] start ] [ RESTART [ [ WITH ] restart ] ] [ CACHE cache ] [ [ NO ] CYCLE ] [ OWNED BY { ...
What happens when a sequence reaches max value in Postgres? How to avoid integer sequence overflow in Postgres How to fix Postgres integer overflow…Continue reading How Postgres DBAs can use pg_stat_io01 March, 2023 In today’s episode 57 of 5mins of Postgres I want to talk about the pg...
(7,2)); CREATE SEQUENCE audit_seq START WITH 1000 INCREMENT BY 1 NOMAXVALUE NOCYCLE NOCACHE; CREATE OR REPLACE TRIGGER audit_emp AFTER INSERT OR UPDATE OR DELETE ON emp FOR EACH ROW DECLARE Time_now DATE; Terminal CHAR(10); BEGIN Time_now:=sysdate; Terminal:=USERENV('TERMINAL'); #从...
Setting ptrack.map_size to a higher value does not affect PTRACK operation, but it is not recommended to set this parameter to a value higher than 1024. Note If you change the ptrack.map_size parameter value, the previously created PTRACK map file is cleared, and tracking newly changed ...
GTM还提供全局值,例如sequence。其他全局属性(如时间戳和通知)将是以下版本中的一个扩展。 关键组件间的交互 如前一节所述,postgresxc有三个主要组件来提供多节点读写的全局一致性,并确定每条语句应该转到哪个datanode和处理该语句。 图1.11给出了postgresxc组件之间的全局事务控制和交互顺序。 如图所示,当协调器开始...
Sequences now contain an additional start_value column (Zoltan Boszormenyi) 序列现在包括一个附加的 start_value。 This supports ALTER SEQUENCE ... RESTART. 由此支持 ALTER SEQUENCESE ... RESTART。 Functions and Operators 函数和操作符 Make numeric zero raised to a fractional power return 0, rathe...
(set, block); } /* set it so new allocations to make use of the keeper block */ set->block = set->keeper; /* Reset block size allocation sequence, too */ set->nextBlockSize = set->initBlockSize; /* Ensure there is only 1 item in the dlist */ Assert(!dlist_is_empty(&set...
The transactions (DMLs) can be captured to change logs with filters, transforms, and aggregations using native database transaction log plug-ins. Later, the sequence of captured DMLs will be replicated to the target database.Both CDC approaches can be used to replicate data ...