cachedTable

Syntax

cachedTable(updateFunc, retentionSeconds)

Arguments

updateFunc is a function without parameters. It must return a table.

retentionSeconds is a positive integer indicating the frequency (in seconds) to update the cached table.

Details

Create a special type of in-memory table: cached table. When querying the cached table, if the length of time since the last update exceeds a specified value,

updateFunc is executed automatically to update the cached table.

Examples

This example defines a unary function, f1, and fixes its argument to produce a partial application with no arguments, f1{t}. f1{t} is passed as the updateFunc to cachedTable.

$ def f1(mutable t){
$     update t set id=id+1
$     return t
$ }
$ t=table(1..5 as id, 15 25 35 45 55 as val)
$ ct=cachedTable(f1{t}, 2);

$ select * from ct;

id	val
2	15
3	25
4	35
5	45
6	55

$ sleep(2100)
$ select * from ct

id	val
3	15
4	25
5	35
6	45
7	55

$ ct=NULL;