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Brian C 2013-11-20 22:53:19 -06:00
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@ -6,7 +6,9 @@ Use a PostgreSQL result cursor from node with an easy to use API.
### why?
Sometimes you need to itterate through a table in chunks. It's extremely inefficient to use hand-crafted `LIMIT` and `OFFSET` queries to do this.
PostgreSQL provides built-in functionality to fetch a "cursor" to your results and page through the cursor. The page size is dynamic and async.
PostgreSQL provides built-in functionality to fetch a "cursor" to your results and page through the cursor efficiently fetching chunks of the results with full MVCC compliance.
This actually ends up pairing very nicely with node's _asyncness_ and handling a lot of data. PostgreSQL is rad.
### example
@ -18,7 +20,7 @@ pg.connect(function(err, client, done) {
//imagine some_table has 30,000,000 results where prop > 100
//lets create a query cursor to efficiently deal with the huge result set
var cursor = client.query(new Cursor('SELECT * FROM some_table WHERE prop > $1', [100])
var cursor = client.query(new Cursor('SELECT * FROM some_table WHERE prop > $1', [100]))
//read the first 100 rows from this cursor
cursor.read(100, function(err, rows) {
@ -41,6 +43,9 @@ pg.connect(function(err, client, done) {
cursor.read(2000, function(err, rows) {
//I think you get the picture, yeah?
//if you dont...open an issue - I'd love to help you out!
//Also - you probably want to use some sort of async or promise library to deal with paging
//through your cursor results. node-pg-cursor makes no asumptions for you on that front.
})
})
});