How to fetch records set with a ttl of -1 in aerospike?

问题

I have so many records in aerospike, i want to fetch the records whose ttl is -1 please provide solution

回答1:

Just to clarify, setting a TTL of -1 in the client means never expire (equivalent to a default-ttl of 0 in the server's aerospike.conf file), while setting a TTL of 0 in the client means inherit the default-ttl for this namespace.

With Predicate Filtering:

If you're using the Java, C, C# and Go clients the easiest way to identify the records with a void time of 0 would be to use a predicate filter.

In the Java app:

Statement stmt = new Statement();
stmt.setNamespace(params.namespace);
stmt.setSetName(params.set);
stmt.setPredExp(
  PredExp.recVoidTime(),
  PredExp.integerValue(0),
  PredExp.integerEqual()
  );

RecordSet rs = client.query(null, stmt);

Without Predicate Filtering:

With other clients that don't yet have predicate filtering (Python, PHP, etc), you would do it all through a stream UDF. The filtering logic would have to live inside the UDF.

ttl.lua

local function filter_ttl_zero(rec)
  local rec_ttl = record.ttl(rec)
  if rec_ttl == 0 then
    return true
  end
  return false
end

local function map_record(rec)
  local ret = map()
  for i, bin_name in ipairs(record.bin_names(rec)) do
    ret[bin_name] = rec[bin_name]
  end
  return ret
end

function get_zero_ttl_recs(stream)
  return stream : filter(filter_ttl_zero) : map(map_record)
end

In AQL:

$ aql
Aerospike Query Client
Version 3.12.0
C Client Version 4.1.4
Copyright 2012-2017 Aerospike. All rights reserved.
aql> register module './ttl.lua'
OK, 1 module added.

aql> AGGREGATE ttl.get_zero_ttl_recs() on test.foo

Alternatively, you could run the stream UDF from the client. The following example is for the Python client:

import aerospike
import pprint

config = {'hosts': [('127.0.0.1', 3000)],
          'lua': {'system_path':'/usr/local/aerospike/lua/',
                  'user_path':'/usr/local/aerospike/usr-lua/'}}
client = aerospike.client(config).connect()

pp = pprint.PrettyPrinter(indent=2)
query = client.query('test', 'foo')
query.apply('ttl', 'get_zero_ttl_recs')
records = query.results()
# we expect a dict (map) whose keys are bin names
# each with the associated bin value
pp.pprint(records)
client.close()

来源：https://stackoverflow.com/questions/45138351/how-to-fetch-records-set-with-a-ttl-of-1-in-aerospike

标签

lua

user-defined-functions

aerospike

ttl

aql