WebJul 2, 2024 · the last argument is the function to apply on every group, in this case nrow to simply count the number of rows in the group. If you want to name the column in the same time you can do: library (plyr) ddply (mydata, c ('Replicate','Node','Day'), function (groupDF) { data.frame (countObservations=nrow (groupDF)) }) Share. WebJan 29, 2024 · I want to be able to count number of rows inserted in a table per second using SQL database. The count has to be for all the rows in the table. Sometimes there could be 100 rows and others 10 etc so this is just for stats. I managed to count rows per day but need more details. Any advise or any scripts would be appreciated. Thanks
How to select the last 2 observations by group? - Stack …
WebFeb 25, 2024 · Like I wrote above to this table we will have to insert around 500-600 rows per second (idenepndly, I mean that will be procedure insertMainTable which will insert one row to this table will be executed 500-600 times per second). According to this efficiency we decide to create this table as partition table. Our idea is to create 32 partitions ... WebROWS_PER_SECOND_DEFAULT_VALUE public static final Long ROWS_PER_SECOND_DEFAULT_VALUE; FIELDS public static final String FIELDS … highrise group ltd
postgresql - Get top two rows per group efficiently - Database ...
WebApr 1, 2024 · And if you really want to get beefy, Postgres allows rows of up to 1.6TB (1600 columns X 1GB max per field)! ... For an individual partition, there are limits on the maximum throughput you can consume on a per-second basis. You can use up to 3,000 Read Capacity Units (RCUs) and up to 1,000 Write Capacity Units (WCUs) on a single … WebSeveral options are available for customizing the DATA-GEN operation. The options are specified as the second parameter of the %DATA built-in function. The parameter can … WebAug 29, 2024 · 1. We have a system that generates 1 million data per second. we have 1 server and should keep data for 1 week (after 1 week we remove older data) Each row has a timestamp field, id field and some other fields. We don't have complex analytic queries, what we want is the database that can handle loading this amount of data and then we … highrise grabs