How to insert floating point numbers in Aerospike KV store?

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I am Using Aerospike 3.40. Bin with floating point value doesn't appear. I am using python client. Please help.

Proficient answered 19/2, 2015 at 19:42 Comment(4)

could you please explain more. its not clear. – Bacteriostasis 19/2, 2015 at 19:56

Milad, Looks like Aerospike KV store does not support floating point numbers. Can any one explain how to achieve this? – Proficient 19/2, 2015 at 20:12

Dear Dhanasekaran S Thanks for your explanation. If you want answers you need to add more data about your problem. ;) – Bacteriostasis 19/2, 2015 at 20:18

I think this link will help you asking good questions. stackoverflow.com/help/how-to-ask – Bacteriostasis 19/2, 2015 at 20:19

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The server does not natively support floats. It supports integers, strings, bytes, lists, and maps. Different clients handle the unsupported types in different ways. The PHP client, for example, will serialize the other types such as boolean and float and store them in a bytes field, then deserialize them on reads. The Python client will be doing that starting with the next release (>= 1.0.38).

However, this approach has the limitation of making it difficult for different clients (PHP and Python, for example) to read such serialized data, as it's not serialized using a common format.

One common way to get around this with floats is to turn them into integers. For example, If you have a bin called 'currency' you can multiply the float by 100, chop off the mantissa, and store it as an integer. On the way out you simply divide by 100. A similar method is to store the significant digits in one bin and the mantissa in another, both of them integer types, and recombine them on the read. So 123.456789 gets stored as v_sig and v_mantissa.

(v_sig, v_mantissa) = str(123.456789).split('.')

on read you would combine the two

v = float(v_sig)+float("0."+str(v_mantissa))

FYI, floats are now supported natively as doubles on the aerospike server versions >= 3.6.0. Most clients, such as the Python and PHP one supports casting floats to as_double.

Nelda answered 21/2, 2015 at 20:46 Comment(10)

Ronen, Thanks for your reply. I have tried using struct.pack to convert float to byte array then insert into aerospike bin. But I am unable to retrieve back from aerospike using python client. Core Dump error thrown. Also how do I find on which column I need to deserialize to convert back to float. Can you please explain in detail? Thanks in advance. – Proficient 5/3, 2015 at 7:31

Hey Dhanasekaran, if you run into a bug you can (and should) open a GitHub issue at the repo github.com/aerospike/aerospike-client-python/issues. A 1.0.38 release is pending soon. If the problem persists please do that. – Nelda 6/3, 2015 at 0:58

Ronen, Thanks for your valuable reply. 1.0.38 is out and I have tested which floating point bins are not getting appeared. Can you please help me out? Update: – Proficient 14/3, 2015 at 8:4

Update: Getting huge list of warnings as given blow while upgrading to 1.0.38 using pip. will this be a reason? Was floating point issue handled in this release? ./aerospike-client-c/include/aerospike/as_udf.h:255:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes] – Proficient 14/3, 2015 at 8:11

Hey, you can actually open a new issue on the GitHub repo, if you're running into a problem, though warnings aren't a bug per-se. No, floating point is not handled in the release, because it would first change on the server before the clients. That's not planned soon. – Nelda 15/3, 2015 at 3:5

Ronen, Thanks for your reply. As per your Answer you mentioned in the beginning of this post, "The PHP client, for example, will serialize the other types such as boolean and float and store them in a bytes field, then deserialize them on reads. The Python client will be doing that starting with the next release (>= 1.0.38)" I expected the python client 1.0.38 may do this. May I now when this fix will be out? What will be my temporary fix till then? Also can you explain in brief for what is the difficulty in supporting Floats in Aerospike? – Proficient 16/3, 2015 at 7:38

Rosen, any inputs. Expecting your valuable reply. – Proficient 18/3, 2015 at 3:14

Okay, I pushed out a new Python aerospike 1.0.40 release, and unsupported types such as floats will now be handled automatically for you. See the release notes (github.com/aerospike/aerospike-client-python/releases/tag/…) and try it for yourself. – Nelda 19/3, 2015 at 0:42

Ronen, thanks and this is a timely release from you. Thanks to you and aerospike team. – Proficient 19/3, 2015 at 7:23

@RonenBotzer Let me know if we have similar thing for Java client as well. – Styria 2/6, 2015 at 17:27

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It is now supported in Aerospike 3.6 version

Holt answered 10/11, 2015 at 11:25 Comment(0)

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The server does not natively support floats. It supports integers, strings, bytes, lists, and maps. Different clients handle the unsupported types in different ways. The PHP client, for example, will serialize the other types such as boolean and float and store them in a bytes field, then deserialize them on reads. The Python client will be doing that starting with the next release (>= 1.0.38).

However, this approach has the limitation of making it difficult for different clients (PHP and Python, for example) to read such serialized data, as it's not serialized using a common format.

One common way to get around this with floats is to turn them into integers. For example, If you have a bin called 'currency' you can multiply the float by 100, chop off the mantissa, and store it as an integer. On the way out you simply divide by 100. A similar method is to store the significant digits in one bin and the mantissa in another, both of them integer types, and recombine them on the read. So 123.456789 gets stored as v_sig and v_mantissa.

(v_sig, v_mantissa) = str(123.456789).split('.')

on read you would combine the two

v = float(v_sig)+float("0."+str(v_mantissa))