[BUG] Mapping parser exception when using array fields (multi-valued) to vectorize

[juntezhang]

What is the bug?

The neural search plugin returns a mapping parser exception when vectorizing a multi-valued field, i.e. a field with an array of values.

This is an example error that is being returned now:

{
    "took": 2,
    "ingest_took": 126,
    "errors": true,
    "items": [
        {
            "index": {
                "_index": "cbd49d4f7d2f4d378b4cf57b45836e65_standard.v1",
                "_id": "4",
                "status": 400,
                "error": {
                    "type": "mapper_parsing_exception",
                    "reason": "failed to parse field [_fulltext_vectorized] of type [knn_vector] in document with id '4'. Preview of field's value: '{knn=[0.0022234858, -0.035359997, -0.04597883, -0.04428486, -0.051025208, 0.07164392, 0.01914906, 0.019771628, 0.040593114, -0.10260139, -0.03696316, -0.026142513, 0.017337762, -0.07099895, 0.06488337, 0.011845544, 0.02151472, -0.0187775, 0.046898145, -0.0057110838, 0.029207353, 0.06773821, 0.022459025, 0.05387708, 0.017910926, 0.017033821, 0.009532835, -0.014977801, -0.08386825, -0.020387044, 0.0028280425, -0.0011476644, 0.009472969, 0.05817717, -0.029048974, 0.0016374304, 0.004514778, -0.026373068, 0.013422251, 0.027697867, -0.045738325, 0.009399452, 0.041691214, 0.020636152, -0.0015610099, -0.035841465, -0.014133858, -0.049274124, 0.019253967, -0.025773656, -0.022655146, -0.0443389, 0.016633136, -0.022475125, 0.024537688, -8.700431E-4, -0.0014111339, -0.044544637, 0.010789341, -0.007992201, -0.0040981085, 0.06470115, -0.05625269, 0.07036083, 0.013696916, 0.016641788, -0.039222337, -0.01709397, 0.022268193, -0.036803477, -0.005889197, -0.0017428886, 0.012373777, -0.0053222124, 5.630651E-4, -0.03114328, 0.022903379, 0.010015105, -0.09750444, -0.039831508, 0.026119227, 0.04916415, -0.03518284, -0.049163043, -0.058863427, 0.019288998, -0.004651093, -0.0068346174, -0.01554544, -0.0318574, 0.005209178, 0.022621633, 0.051216673, 0.060406737, -0.019851688, -0.020140702, -0.050286926, 0.04648004, 0.028480874, -0.0068861614, -0.038972907, 0.027410269, 0.039639413, 0.008856761, 0.04474063, 0.019777315, 0.04533569, -0.04286205, -0.051645227, 0.021571778, 0.026019301, 0.03279914, 0.007847676, 0.018339507, -0.025968133, -0.011049657, 0.012097716, -0.026544329, -0.017996104, 0.06355469, -0.044277992, -0.021543628, -0.05254539, 0.01735264, 0.09401051, -0.0014846673, 0.05555623, -0.056472104, 0.011484598, -0.006637214, 0.0029666661, -0.01887005, 0.015547031, 0.038509913, 0.05672793, -0.011875595, 0.031623192, -0.015370892, -0.005386455, -2.690006E-4, 0.015663855, -0.026425289, 0.014581022, -0.008019377, 0.009754192, -0.003575142, 4.3682655E-4, -0.0017491437, 0.07600901, -0.0075051626, 0.07084152, 0.032232024, 0.02919557, 0.00843389, 0.057466295, -0.0019165685, -0.047833677, 0.061958246, 0.0022890286, 0.04325089, -0.003123286, -0.064216696, -0.029908644, 0.026410121, 0.028926784, -0.009601688, -0.014144011, 0.0045824777, 0.022797842, 0.012890149, 0.001131833, 0.045201935, -0.008825862, -0.07638976, 0.027312782, 0.019408751, -0.03865251, 0.034349024, -0.0026372483, 0.030560758, -0.044272523, -0.012122316, 0.09661386, -0.02256945, 0.0062002423, 0.08038384, 0.00446424, 0.04955032, -0.0055512907, -0.0026584843, 0.033093628, -0.00980246, -0.0043738247, 0.0063798116, -0.021291338, 0.08625754, -0.03646296, -0.0487054, -0.011571014, -0.028801179, -0.025787387, 0.010490938, 0.003622506, -0.008190592, 0.0470385, -0.008248904, 0.0077942447, 0.020922707, -0.02686499, 0.10285625, 0.07073387, 0.010794978, -0.07248987, -0.095100045, 0.037754994, -0.021165807, -0.03498472, 0.05648951, 0.03388164, -0.029221494, -0.022435514, -9.771192E-4, -0.007607546, 0.03615137, -0.011542751, 0.006586234, -5.4524833E-4, 0.046416942, -0.017986912, -0.04261404, 0.024626905, -0.047040798, -0.033530287, -0.07259043, 0.035305493, -0.057256985, 0.0099811265, 0.026785806, -0.0038653421, -0.0112647405, -0.04575772, -0.008731651, -0.043923464, 0.0221416, 0.02560391, 0.0151665285, 0.050818447, 0.050663058, 0.04115714, 0.0023678623, -0.035306197, -0.084681004, 0.023927884, -0.029665923, 0.01732664, 0.023585321, -0.09153603, 0.011902792, 0.014034639, -0.016245406, -0.028288625, -0.033873256, 0.003353059, 0.053711176, 0.020320253, 0.047022935, 0.017852021, -0.004466688, 0.01584446, 0.013000825, 0.010487262, -0.01842222, 4.192322E-4, -0.023091855, -0.008465306, 0.006698411, 0.093931206, -0.0033818672, 0.010160068, 0.022345843, 0.060346037, 0.013339592, 0.022352727, -0.03324387, 0.04028923, -0.03625564, -0.014581585, -0.041865215, 0.0026519487, -0.05310946, 0.048063193, 0.0455302, -0.00788708, -0.015701849, -0.018672984, -0.020087173, 0.019534169, 0.0039749774, 0.027360147, -0.031662032, 0.030710638, 0.03512735, 0.048522025, -0.062308006, -0.040190976, -0.032376904, -0.007325561, 0.0063507366, -0.011564964, 0.020408038, -0.0019888023, -0.03727972, -0.012309679, 0.047042694, 0.034211647, -0.051655166, 0.035434086, 0.061370537, 0.008199342, 0.015067597, 0.014224768, -0.012992773, 0.0077665015, 0.0095752645, -0.041191015, -0.03864752, -0.045672048, -0.03465211, -0.035151068, 0.04701482, -0.109876476, -0.046479177, 0.005260139, 0.006503089, -0.024829691, 0.0110920165, 0.019567052, -0.0012819336, -0.0050430726, -0.020127827, -0.026641257, -0.014725637, 0.11150941, 0.060796894, 0.015541844, 0.0066707935, 0.008368974, -0.052622072, -0.04412639, 0.030551784, -0.026100276, -0.005876258, 0.005038192, -0.026032347, 0.008800204, 0.026139341, 5.213012E-4, 0.0065577067, -0.05505976, 0.0330918, -0.008326094, -0.0396188, 0.0025030947, 0.026069254, 0.023491057, 0.02984612, -0.014990682, -0.06625647, -0.0046483255, 0.02964674, 0.0015031297, -0.015714135, -0.02850169, -0.0055536265, 0.0066902246, -0.007848156, -7.6600706E-4, 0.04313042, -0.015721817, 0.005434864, 0.024475155, -0.03546163, 0.017684974, 0.010431305, -3.305352E-5, -0.09190294, 0.008938634, 0.04076338, 0.0041706664, -0.016136287, -0.05161017, 0.053476337, 0.015459943, -0.023108725, 0.039780494, 0.024200078, -0.0838633, 0.06269914, -0.05062816, -0.06510745, -0.0025781589, 0.07451038, -0.02091673, 0.044712655, -0.04894433, 0.028831981, 0.034012303, -0.0023153357, -0.04997018, -0.075276874, 0.030397471, 0.014266653, 0.02622722, 0.0047556623, -0.038664035, 0.0015079024, 0.0032861913, -0.03532062, 0.046805825, -0.019798208, -0.006433615, -0.018331818, 0.031093929, -0.049762033, 0.036538515, 0.0041088043, -0.028467398, 0.03458563, 0.012369647, 0.0052060084, -0.023429459, -0.0024426244, 0.001823067, 0.019299336, 0.017141998, 0.0031919046, -0.07006116, -0.041087616, -0.0058480343, 0.058516745, 0.032500196, 0.020187413, 0.006855557, -0.012927736, 0.0022162858, -0.06437811, -0.009692816, 0.0039992286, 0.05996473, -0.021586077, -0.040819686, -0.024930276, 0.042631, -0.10328431, 0.014596877, 0.05685491, -0.013609369, 0.016496915, -0.0033860805, -0.021132236, 0.037780456, -0.024468174, -0.009608023, -0.023516266, -0.03733314, -0.006833277, -0.016395053, 0.0070661553, -0.0020087238, -0.056234054, -0.0077887755, 0.01678384, -0.025155602, -0.023703402, 0.028658977, -0.012632824, -0.015815027, -0.11297324, 0.043369632, 0.02495586, 0.028703807, 0.03492561, -0.011649105, 0.031252336, -0.022072453, -0.04119532, 0.07378223, -0.02075963, 0.016274827, -0.013694347, -0.016307695, 0.001300256, -0.036652822, 0.034588035, 1.8075841E-33, -0.0013329218, -0.04732977, 0.00996674, -0.029841881, -0.038386185, -0.04705207, 0.009828712, -0.0120018525, 0.01957792, -0.002065031, -0.014865287, 0.0020658378, 0.0045970078, 0.018740244, -0.023252893, 0.022443427, -0.06343757, -0.025586, -0.0037992818, -0.03004964, 0.013667456, -0.018568411, -0.028990187, 0.009482019, -0.06301416, -0.013344209, 0.017539762, 0.003624506, 0.03288363, 0.01715692, -0.006730218, 0.03863204, -0.0082167955, -0.001636874, 0.046989333, 0.021004293, -0.006706133, -0.00930357, 0.045862682, -0.012914553, -0.037851233, -0.08964776, -0.03390127, 0.044933114, -0.031888396, -0.07620988, -0.0020800682, 0.012426403, -0.07331452, 0.0076321703, -0.040095836, -0.038698476, 0.0017401874, 0.024982955, 0.0014869848, 0.028290188, -0.07428447, 0.034169685, -0.079832755, -0.038579136, 0.008933051, -0.006873085, 0.07893267, -0.01009624, 0.022934059, 0.009754162, 0.014792834, 0.060311176, 0.03243314, -0.006624844, -0.034329288, -0.007510828, 0.050048847, -0.004304317, 0.02510955, 0.021710811, 0.0307444, -0.0021874288, 0.015229203, 0.047972646, -0.039895188, 0.012476255, 0.02703852, 0.09733716, 0.06299362, 0.010616695, -0.0046062027, 0.044824835, 0.0061520166, -0.006623393, 0.09986233, 0.02122441, 0.055295713, 0.001532098, 0.012163582, 0.0018900193, 1.3753287E-4, 0.015736612, -0.0063640936, 0.02673144, 0.035468813, -0.0111199105, 0.037446886, 0.02064939, -0.0016271996, -0.0027657875, -0.0046730214, -0.034245532, -0.0066429153, -0.018573927, -0.015771288, -0.0057752146, 0.028279593, 0.052879356, 0.070884794, -0.012343979, -0.022187816, -0.027230598, -0.057736237, 0.017123338, 0.05645999, -0.029136037, 0.018418355, 0.03351841, 0.034862872, 0.065103404, -0.019825313, -0.018390888, -0.021154428, -0.027518576, 0.043791376, -0.0072945477, 0.055040803, 0.016504884, 0.035224862, -0.032629233, -0.014595143, -0.05553731, -0.0298001, 0.012567941, -0.017359268, 0.07743764, -0.019259855, 0.028261904, -0.0067304126, -0.00778184, 0.035145696, -0.03499496, 0.043350633, 0.032245047, 0.057637613, -0.008384977, 0.025610931, -0.038622297, -0.076179355, -0.011728838, -0.052147277, -0.027141817, 0.0031384584, 0.057403617, -0.03149885, -0.07207539, -0.031181404, 0.034629732, 0.0046421094, 0.05123516, 0.048581116, 0.0026500921, 0.0069391984, -0.03898162, -0.057580877, -0.01872841, -0.023232281, 0.008946941, 0.019862209, 0.03084452, -0.02284944, -0.04255101, 0.018957136, -0.007989339, -0.015704466, 0.02101821, -0.010253275, -0.09247238, 0.006889824, -0.050714917, -0.013169677, 0.010791484, -0.01209312, 0.052326225, -0.015788112, -0.03533834, 0.018179337, -0.02753798, 0.03551319, -0.008871127, -0.0095051015, 0.0124840215, 0.046523266, 0.04466758, 0.03454243, 0.03360791, 0.010210552, -0.015331205, -0.0956788, -0.0251008, -0.014605966, -0.060167354, 0.004341411, -0.00951521, 0.042475585, 0.011100874, -0.03497262, -0.043598466, -0.00374743, -0.050682824, 0.07120098, 0.028575115, 0.014855652, 0.055505354, -0.020940848, -0.02267042, -0.007144853, 0.014108742, 0.023034291, -0.013486119, -0.0065789875, -0.04207302, -0.05829398, 0.030400414, -0.04194086, -0.041272007, 0.008843035, 0.057984617, 0.0541426, 0.007082873, 0.050124623, 0.05790826, 0.07747711, 0.030769683, -0.036104802, -0.030300677, -0.041837405, 0.024292568, 0.054189228, -0.015752152, 0.0042987284, 0.012297104, -0.059740506, 0.024804313, -0.01837132, 0.027748019, -0.021990905, 0.020890879, -7.413028E-4, -0.02815649, -0.017462464, 0.022596458, -0.0059415614, 0.04076583, 0.04511265, 0.08606662, 0.045326464, -0.020486556, 0.027558114, -0.063122466, -0.04743531, -0.022816103, -0.013700926, 0.015591036, -0.065042675, 0.005773686, -0.029538473]}'",
                    "caused_by": {
                        "type": "json_parse_exception",
                        "reason": "Current token (START_OBJECT) not numeric, can not use numeric value accessors\n at [Source: (byte[])\"{\"_fulltext_source\":[\"cowboy\"],\"_fulltext_vectorized\":[{\"knn\":[0.0022234858,-0.035359997,-0.04597883,-0.04428486,-0.051025208,0.07164392,0.01914906,0.019771628,0.040593114,-0.10260139,-0.03696316,-0.026142513,0.017337762,-0.07099895,0.06488337,0.011845544,0.02151472,-0.0187775,0.046898145,-0.0057110838,0.029207353,0.06773821,0.022459025,0.05387708,0.017910926,0.017033821,0.009532835,-0.014977801,-0.08386825,-0.020387044,0.0028280425,-0.0011476644,0.009472969,0.\"[truncated 9087 bytes]; line: 1, column: 92]"
                    }
                }
            }
        }
    ]
}

How can one reproduce the bug?

Add in the mapping the vectorized field configuration as explained in the tutorial of Sease.

Create an ingest pipeline with this in the request body:

{
    "neural_pipeline": {
        "description": "Neural search pipeline",
        "processors": [
            {
                "text_embedding": {
                    "model_id": "<MODEL_ID>",
                    "field_map": {
                        "_fulltext_source": "_fulltext_vectorized"
                    }
                }
            }
        ]
    }
}

Then index the following document to the Bulk API:

    {"index":{"_id":4}}
    {"_fulltext_source":["cowboy"]}

It consists of a field with as value an array with 1 value.

What is the expected behavior?

The expected behavior is that it would vectorize all values in the array and use these values in the ANN search.

What is your host/environment?

MacOS 13.4.1, but running in Docker with latest Ubuntu.

Do you have any screenshots?

N/A

Do you have any additional context?

I am happy to contribute to a solution.

[navneet1v]

@zane-neo can you please look into this issue.

[zane-neo]

@juntezhang I can reproduce this issue with index setting like below:

{
    "settings": {
        "index": {
            "knn": true,
            "knn.algo_param.ef_search": 100,
            "refresh_interval": -1,
            "default_pipeline": "my-pipeline"
        },
        "number_of_shards": 1,
        "number_of_replicas": 0
    },
    "mappings": {
        "properties": {
            "text_knn": {
                "type": "knn_vector",
                "dimension": 384,
                "method": {
                    "name": "hnsw",
                    "space_type": "l2",
                    "engine": "nmslib",
                    "parameters": {
                        "ef_construction": 128,
                        "m": 24
                    }
                }
            }
        }
    }
}

With this index setting, you'll get mapping exception indeed because the created knn vectors of the input list are encapsulated into a nested list. Please try to create your index like below:

{
    "settings": {
        "index": {
            "knn": true,
            "knn.algo_param.ef_search": 100,
            "refresh_interval": -1,
            "default_pipeline": "my-pipeline"
        },
        "number_of_shards": 1,
        "number_of_replicas": 0
    },
    "mappings": {
        "properties": {
            "text_knn": {
                "type": "nested",
                "properties": {
                    "knn": {
                        "type": "knn_vector",
                        "dimension": 384,
                        "method": {
                            "name": "hnsw",
                            "space_type": "l2",
                            "engine": "nmslib",
                            "parameters": {
                                "ef_construction": 128,
                                "m": 24
                            }
                        }
                    }
                }
            }
        }
    }
}

And try again, thanks.

[zane-neo]

@juntezhang Closing this issue, if you still facing errors, please let us know.

[juntezhang]

I can confirm that this solutions works! Sorry for the late response.