분류 전체보기 (286) 썸네일형 리스트형 oltpbenchmark oltpbenchmark (tool) http://oltpbenchmark.com/wiki/index.php?title=Main_PageMain PageBenchmarking is an important, yet often overlooked, aspect of any database management system (DBMS) research and development effort. Despite several advancements over the last decades, the deployment of a comprehensive testing platform with a diverse set of data sets and workloads is still non-trivial. In many c.. count_distinct improvements count_distinct improvementsAlmost a year ago, I wrote a custom experimental aggregate replacing COUNT(DISTINCT). The problem with the native COUNT(DISTINCT) is that it forces a sort on the input relation, and when the amount of data is significant (say, tens of millions rows), that may be a significant performance drag. And sometimes we really need to do COUNT(DISTINCT).Extensibility is one of t.. postgresql upgrade postgresql upgrade 하는 방법1. dump 백업으로 복구하는 방법. 이 방식은 데이터 싸이즈가 큰 경우 downtime이 많이 발생 하므로 사용하기 힘든점이 있다. 2. pg_upgrade 사용하는 방법. 이 방식 또한 downtime이 발생한다. 내부적으로 dump로 restore하는 방식이다.* http://www.postgresql.org/docs/9.3/static/upgrading.html 3. Slony-I(Community), xDB (EDB) Replication 이 두 가지 방식은 Replication을 이용해서 upgrade를 한다. 두가지 모두 DB 버전이 다른 경우에도 사용이 가능하며, downtime을 최소화 할 수 있는 방법이다. Slony-I(Community) .. trigger-overhead 출처 : http://www.openscg.com/2014/05/trigger-overhead-part-2/I found a bit more time dig into timing of triggers and their overhead so I wanted to see how much overhead the choice of procedural language affected performance. I followed the same testing methodology from my original trigger test. For this test I created an empty trigger in the following languages:PL/pgSQLCREATE FUNCTION empty_trigg.. 9.4에 추가 되는 Statistics Collector VIEW pg_stat_archiver 9.4에 추가 되는 Statistics Collector VIEW Table 27-3. pg_stat_archiver ViewColumnTypeDescriptionarchived_countbigintNumber of WAL files that have been successfully archivedlast_archived_waltextName of the last WAL file successfully archivedlast_archived_timetimestamp with time zoneTime of the last successful archive operationfailed_countbigintNumber of failed attempts for archiving WAL fileslast_fail.. Making sorts happen in memory instead of on disk Making sorts happen in memory instead of on diskIf you have disk-based sorts occurring frequently, you can find the size of the largest of the frequent queries and then set this as the standard threshold for sorts. The parameter for this in/var/lib/pgsql/data/postgresql.conf is 'work_mem'. For example, if you had frequent disk-spaced sorts using up to 64MB, you would set the following in /var/li.. 디스크 IO 성능 - I/O 스케줄러 출처 : http://www.mimul.com/pebble/default/2012/05/12/1336793032150.html디스크 IO 성능 - I/O 스케줄러I/O SchedulerI/O 스케줄러는 디스크 I/O 를 효율화하기 위한 기능이다. Kernel 2.6.10에서 deadline, noop, cfq, anticipatory 4 종류가 있으며, 기본은 cfq. OS 내에 있는 I/O scheduler 디자인을 결정하는 핵심 요소가 'throughput vs. latency(response time)'이다. 그리고 우리가 운영하는 서비스에서 특히 File I/O가 맞은 아키텍처에서는 튜닝 포인트 중에 하나라는 것도 알아두어야 한다. I/O Elevator?I/O Scheduler는 Request .. Install Nmon - Monitor Linux System Performance using Java Analyzer Install Nmon - Monitor Linux System Performance using Java AnalyzerJanuary 3, 2014 | By Pungki Arianto in MONITORING, OPEN SOURCE TOOLSThere are a lot of resource monitoring tools on the internet. On of the most used monitoring tool is nmon. With this tool, you can almost monitoring everything. From CPU, Memory, Disks, Network and even Filesystem can be monitored by nmon.What is nmon and Java Nm.. 이전 1 2 3 4 ··· 36 다음