JSONB spaces in text presentation

On 9/24/2014 12:23 AM, Ilya I. Ashchepkov wrote:

Is spaces is necessary in text presentation of JSONB?
In my data resulting text contains ~12% of spaces.

can you show us an example of this?

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I'm sorry about sending email several times. I haven't understand, was it
sent by gmail or not.

On Wed, Sep 24, 2014 at 2:30 PM, John R Pierce <pierce@hogranch.com> wrote:

On 9/24/2014 12:23 AM, Ilya I. Ashchepkov wrote:

Is spaces is necessary in text presentation of JSONB?
In my data resulting text contains ~12% of spaces.

can you show us an example of this?

One record
# select data from events.data limit 1;
{"can": {"lls": {"1": 76.4}, "mhs": 4674.85, "rpm": 168.888, "speed": 74,
"runned": 166855895, "fuel_consumption": 74213.5}, "crc": 10084, "gps": 1,
"gsm": {"signal": 100}, "lls": {"1": 733, "2": 717}, "used": 19, "speed":
87.4, "valid": 1, "msg_id": 89, "runned": 72.75, "boot_no": 256, "digital":
{"in": {"1": 1, "2": 0, "3": 0, "4": 0, "5": 0, "6": 0}, "out": {"1": 0,
"2": 0}}, "visible": 20, "ignition": 1, "location": {"course": 265,
"altitude": 143, "latitude": 55.127888997395836, "longitude":
80.8046142578125}, "protocol": 4, "coldstart": 1, "timesource": "terminal",
"receiver_on": 1, "external_power": 28.07, "internal_power": 4.19}

Whitespacis percents in this record:
# select array_length(regexp_split_to_array(data::text, text ' '),
1)*100./length(data::text) from events.data limit 1;
?column?
---------------------
12.3417721518987342

Whitespace in test data
# select count(*),avg(array_length(regexp_split_to_array(data::text, text
' '), 1)*100./length(data::text)) from events.data ;
count | avg
--------+---------------------
242222 | 12.3649234646118312

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john r pierce 37N 122W
somewhere on the middle of the left coast

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С уважением,
Ащепков Илья koctep@gmail.com

On Wed, Sep 24, 2014 at 2:44 AM, Ilya I. Ashchepkov <koctep@gmail.com> wrote:

I'm sorry about sending email several times. I haven't understand, was it
sent by gmail or not.

On Wed, Sep 24, 2014 at 2:30 PM, John R Pierce <pierce@hogranch.com> wrote:

On 9/24/2014 12:23 AM, Ilya I. Ashchepkov wrote:

Is spaces is necessary in text presentation of JSONB?
In my data resulting text contains ~12% of spaces.

can you show us an example of this?

One record
# select data from events.data limit 1;
{"can": {"lls": {"1": 76.4}, "mhs": 4674.85, "rpm": 168.888, "speed": 74,
"runned": 166855895, "fuel_consumption": 74213.5}, "crc": 10084, "gps": 1,
"gsm": {"signal": 100}, "lls": {"1": 733, "2": 717}, "used": 19, "speed":
87.4, "valid": 1, "msg_id": 89, "runned": 72.75, "boot_no": 256, "digital":
{"in": {"1": 1, "2": 0, "3": 0, "4": 0, "5": 0, "6": 0}, "out": {"1": 0,
"2": 0}}, "visible": 20, "ignition": 1, "location": {"course": 265,
"altitude": 143, "latitude": 55.127888997395836, "longitude":
80.8046142578125}, "protocol": 4, "coldstart": 1, "timesource": "terminal",
"receiver_on": 1, "external_power": 28.07, "internal_power": 4.19}

Whitespacis percents in this record:
# select array_length(regexp_split_to_array(data::text, text ' '),
1)*100./length(data::text) from events.data limit 1;
?column?
---------------------
12.3417721518987342

Whitespace in test data
# select count(*),avg(array_length(regexp_split_to_array(data::text, text '
'), 1)*100./length(data::text)) from events.data ;
count | avg
--------+---------------------
242222 | 12.3649234646118312

For jsonb (unlike json), data is not actually stored as json but in a
binary format. It will generally be much larger than the text
representation in fact but in exchange for that many operations will
be faster. The spaces you see are generated when the jsonb type is
converted to text for output. I actually think it's pretty reasonable
to want to redact all spaces from such objects in all cases where
converstion to text happens (output functions, xxxto_json, etc)
because ~12% savings are nothing to sneeze at when moving large
documents in and out of the database.

On the flip side, a more verbose prettification would be pretty nice
too. I wonder if a hypothetical GUC is the best way to control this
behavior...

merlin

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On 09/24/2014 12:44 AM, Ilya I. Ashchepkov wrote:

I'm sorry about sending email several times. I haven't understand, was
it sent by gmail or not.

On Wed, Sep 24, 2014 at 2:30 PM, John R Pierce <pierce@hogranch.com
<mailto:pierce@hogranch.com>> wrote:

On 9/24/2014 12:23 AM, Ilya I. Ashchepkov wrote:

Is spaces is necessary in text presentation of JSONB?
In my data resulting text contains ~12% of spaces.

can you show us an example of this?

One record
# select data from events.data limit 1;
{"can": {"lls": {"1": 76.4}, "mhs": 4674.85, "rpm": 168.888, "speed":
74, "runned": 166855895, "fuel_consumption": 74213.5}, "crc": 10084,
"gps": 1, "gsm": {"signal": 100}, "lls": {"1": 733, "2": 717}, "used":
19, "speed": 87.4, "valid": 1, "msg_id": 89, "runned": 72.75, "boot_no":
256, "digital": {"in": {"1": 1, "2": 0, "3": 0, "4": 0, "5": 0, "6": 0},
"out": {"1": 0, "2": 0}}, "visible": 20, "ignition": 1, "location":
{"course": 265, "altitude": 143, "latitude": 55.127888997395836,
"longitude": 80.8046142578125}, "protocol": 4, "coldstart": 1,
"timesource": "terminal", "receiver_on": 1, "external_power": 28.07,
"internal_power": 4.19}

Whitespacis percents in this record:
# select array_length(regexp_split_to_array(data::text, text ' '),
1)*100./length(data::text) from events.data limit 1;
?column?
---------------------
12.3417721518987342

Whitespace in test data
# select count(*),avg(array_length(regexp_split_to_array(data::text,
text ' '), 1)*100./length(data::text)) from events.data ;
count | avg
--------+---------------------
242222 | 12.3649234646118312

The only thing I can of is to use json not jsonb. Modified example taken
from docs:

http://www.postgresql.org/docs/9.4/static/datatype-json.html

test=# SELECT '{"bar":"baz","balance":7.77,"active":false}'::jsonb;
jsonb
--------------------------------------------------
{"bar": "baz", "active": false, "balance": 7.77}

test=# SELECT '{"bar":"baz","balance":7.77,"active":false}'::json;
json
---------------------------------------------
{"bar":"baz","balance":7.77,"active":false}

json will return exactly what was put in.

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Adrian Klaver
adrian.klaver@aklaver.com

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This is interesting. Most binary encoding methods I use produce smaller
files than the text files for the same content.
Having read your mail, I've realized that I have no reason to accept the
same from the jsonb. I did a quick google search to see if it is wrong to
expect binary encoding to decrease size and saw that I'm not alone (which
still does not mean I'm being reasonable).
This project: http://ubjson.org/#size is one of the hits which mentions
some nice space gains thanks to binary encoding.

The "much larger" part is a bit scary. Is this documented somewhere?

Best regards
Seref

On Wed, Sep 24, 2014 at 2:44 PM, Merlin Moncure <mmoncure@gmail.com> wrote:

On 09/24/2014 07:22 AM, Seref Arikan wrote:

This is interesting. Most binary encoding methods I use produce smaller
files than the text files for the same content.
Having read your mail, I've realized that I have no reason to accept the
same from the jsonb. I did a quick google search to see if it is wrong
to expect binary encoding to decrease size and saw that I'm not alone
(which still does not mean I'm being reasonable).
This project: http://ubjson.org/#size is one of the hits which mentions
some nice space gains thanks to binary encoding.

The "much larger" part is a bit scary. Is this documented somewhere?

I believe Merlin is referring to the issue in this thread:

/messages/by-id/27839.1407467863@sss.pgh.pa.us

Best regards
Seref

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adrian.klaver@aklaver.com

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IMHO, prettification is useful only for debugging.
It would be nice to have a session variable for the debug output with
spaces, new lines and indentation.

On Wed, Sep 24, 2014 at 8:44 PM, Merlin Moncure <mmoncure@gmail.com> wrote:

On Wed, Sep 24, 2014 at 2:44 AM, Ilya I. Ashchepkov <koctep@gmail.com>
wrote:

I'm sorry about sending email several times. I haven't understand, was it
sent by gmail or not.

On Wed, Sep 24, 2014 at 2:30 PM, John R Pierce <pierce@hogranch.com>

wrote:

On 9/24/2014 12:23 AM, Ilya I. Ashchepkov wrote:

Is spaces is necessary in text presentation of JSONB?
In my data resulting text contains ~12% of spaces.

can you show us an example of this?

One record
# select data from events.data limit 1;
{"can": {"lls": {"1": 76.4}, "mhs": 4674.85, "rpm": 168.888, "speed": 74,
"runned": 166855895, "fuel_consumption": 74213.5}, "crc": 10084, "gps":

1,

"gsm": {"signal": 100}, "lls": {"1": 733, "2": 717}, "used": 19, "speed":
87.4, "valid": 1, "msg_id": 89, "runned": 72.75, "boot_no": 256,

"digital":

{"in": {"1": 1, "2": 0, "3": 0, "4": 0, "5": 0, "6": 0}, "out": {"1": 0,
"2": 0}}, "visible": 20, "ignition": 1, "location": {"course": 265,
"altitude": 143, "latitude": 55.127888997395836, "longitude":
80.8046142578125}, "protocol": 4, "coldstart": 1, "timesource":

"terminal",

"receiver_on": 1, "external_power": 28.07, "internal_power": 4.19}

Whitespacis percents in this record:
# select array_length(regexp_split_to_array(data::text, text ' '),
1)*100./length(data::text) from events.data limit 1;
?column?
---------------------
12.3417721518987342

Whitespace in test data
# select count(*),avg(array_length(regexp_split_to_array(data::text,

text '

'), 1)*100./length(data::text)) from events.data ;
count | avg
--------+---------------------
242222 | 12.3649234646118312

For jsonb (unlike json), data is not actually stored as json but in a
binary format. It will generally be much larger than the text
representation in fact but in exchange for that many operations will
be faster. The spaces you see are generated when the jsonb type is
converted to text for output. I actually think it's pretty reasonable
to want to redact all spaces from such objects in all cases where
converstion to text happens (output functions, xxxto_json, etc)
because ~12% savings are nothing to sneeze at when moving large
documents in and out of the database.

On the flip side, a more verbose prettification would be pretty nice
too. I wonder if a hypothetical GUC is the best way to control this
behavior...

merlin

--
С уважением,
Ащепков Илья koctep@gmail.com

With the same data:

# create cast (jsonb as bytea) without function;
# select
sum(length(data::text))::float/sum(octet_length((data::jsonb)::bytea)) from
data.packets;
?column?
-------------------
0.630663654967513

and 0.554666142734544 without spaces

On Wed, Sep 24, 2014 at 9:22 PM, Seref Arikan <serefarikan@gmail.com> wrote:

This is interesting. Most binary encoding methods I use produce smaller
files than the text files for the same content.
Having read your mail, I've realized that I have no reason to accept the
same from the jsonb. I did a quick google search to see if it is wrong to
expect binary encoding to decrease size and saw that I'm not alone (which
still does not mean I'm being reasonable).
This project: http://ubjson.org/#size is one of the hits which mentions
some nice space gains thanks to binary encoding.

The "much larger" part is a bit scary. Is this documented somewhere?

Best regards
Seref

On Wed, Sep 24, 2014 at 2:44 PM, Merlin Moncure <mmoncure@gmail.com>
wrote:

On Wed, Sep 24, 2014 at 2:44 AM, Ilya I. Ashchepkov <koctep@gmail.com>
wrote:

I'm sorry about sending email several times. I haven't understand, was

it

sent by gmail or not.

On Wed, Sep 24, 2014 at 2:30 PM, John R Pierce <pierce@hogranch.com>

wrote:

On 9/24/2014 12:23 AM, Ilya I. Ashchepkov wrote:

Is spaces is necessary in text presentation of JSONB?
In my data resulting text contains ~12% of spaces.

can you show us an example of this?

One record
# select data from events.data limit 1;
{"can": {"lls": {"1": 76.4}, "mhs": 4674.85, "rpm": 168.888, "speed":

74,

"runned": 166855895, "fuel_consumption": 74213.5}, "crc": 10084, "gps":

1,

"gsm": {"signal": 100}, "lls": {"1": 733, "2": 717}, "used": 19,

"speed":

87.4, "valid": 1, "msg_id": 89, "runned": 72.75, "boot_no": 256,

"digital":

{"in": {"1": 1, "2": 0, "3": 0, "4": 0, "5": 0, "6": 0}, "out": {"1": 0,
"2": 0}}, "visible": 20, "ignition": 1, "location": {"course": 265,
"altitude": 143, "latitude": 55.127888997395836, "longitude":
80.8046142578125}, "protocol": 4, "coldstart": 1, "timesource":

"terminal",

"receiver_on": 1, "external_power": 28.07, "internal_power": 4.19}

Whitespacis percents in this record:
# select array_length(regexp_split_to_array(data::text, text ' '),
1)*100./length(data::text) from events.data limit 1;
?column?
---------------------
12.3417721518987342

Whitespace in test data
# select count(*),avg(array_length(regexp_split_to_array(data::text,

text '

'), 1)*100./length(data::text)) from events.data ;
count | avg
--------+---------------------
242222 | 12.3649234646118312

For jsonb (unlike json), data is not actually stored as json but in a
binary format. It will generally be much larger than the text
representation in fact but in exchange for that many operations will
be faster. The spaces you see are generated when the jsonb type is
converted to text for output. I actually think it's pretty reasonable
to want to redact all spaces from such objects in all cases where
converstion to text happens (output functions, xxxto_json, etc)
because ~12% savings are nothing to sneeze at when moving large
documents in and out of the database.

On the flip side, a more verbose prettification would be pretty nice
too. I wonder if a hypothetical GUC is the best way to control this
behavior...

merlin

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С уважением,
Ащепков Илья koctep@gmail.com

Check slides 17-20 of
http://www.sai.msu.su/~megera/postgres/talks/hstore-dublin-2013.pdf to
understand, what 'binary format' means. The slides describes binary storage
for nested hstore, not jsonb, but you'll get the idea.

On Wed, Sep 24, 2014 at 6:22 PM, Seref Arikan <serefarikan@gmail.com> wrote:

On 9/24/2014 7:22 AM, Seref Arikan wrote:

This is interesting. Most binary encoding methods I use produce
smaller files than the text files for the same content.

'1' vs INTEGER 1 ... 1 byte vs 4 bytes.

now add metadata necessary to represent the original json structure.

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john r pierce 37N 122W
somewhere on the middle of the left coast

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Thanks Oleg, I'll check the slides.

On Wed, Sep 24, 2014 at 8:07 PM, Oleg Bartunov <obartunov@gmail.com> wrote: