Too few rows expected by Planner on partitioned tables

A description of what you are trying to achieve and what results you expect:
Our database is growing on a daily basis by about 2.5million rows per table (2 at the moment). Because of that, we decided to partition the data, especially, as we are pre-aggregating the data for weeks, months, quarters and years. Every aggregation is stored in a separate partition:

Days: ..._yYYYYmMMd  (base data)
Weeks: ..._yYYYYmMMw (aggregated all weeks of the month)
month: ..._yYYYYmMM (aggregated month)
etc.


Our problem is, that the planner always predicts one row to be returned, although only a part of the primary key is queried. This problem exceeds feasibility of performance rapidly - a query only involving a few days already takes dozens of seconds. All tables are analyzed and pg_stats looks reasonable IMHO.


PostgreSQL version number you are running:
postgres=# SELECT version();
                                                     version                                                      
------------------------------------------------------------------------------------------------------------------
 PostgreSQL 12.3 (Debian 12.3-1.pgdg100+1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 8.3.0-6) 8.3.0, 64-bit
(1 Zeile)

postgres=# SELECT name, current_setting(name), source
postgres-#   FROM pg_settings
postgres-#   WHERE source NOT IN ('default', 'override');
postgres=# SELECT name, current_setting(name), source
  FROM pg_settings
  WHERE source NOT IN ('default', 'override');
              name              |             current_setting             |        source        
--------------------------------+-----------------------------------------+----------------------
 application_name               | psql                                    | client
 checkpoint_completion_target   | 0.9                                     | configuration file
 client_encoding                | UTF8                                    | client
 cluster_name                   | 12/main                                 | configuration file
 DateStyle                      | ISO, DMY                                | configuration file
 default_text_search_config     | pg_catalog.german                       | configuration file
 dynamic_shared_memory_type     | posix                                   | configuration file
 effective_cache_size           | 6GB                                     | configuration file
 effective_io_concurrency       | 200                                     | configuration file
 enable_partitionwise_aggregate | on                                      | configuration file
 enable_partitionwise_join      | on                                      | configuration file
 external_pid_file              | /var/run/postgresql/12-main.pid         | configuration file
 lc_messages                    | de_DE.UTF-8                             | configuration file
 lc_monetary                    | de_DE.UTF-8                             | configuration file
 lc_numeric                     | de_DE.UTF-8                             | configuration file
 lc_time                        | de_DE.UTF-8                             | configuration file
 listen_addresses               | *                                       | configuration file
 log_line_prefix                | %m [%p] %q%u@%d                         | configuration file
 log_timezone                   | Etc/UTC                                 | configuration file
 maintenance_work_mem           | 512MB                                   | configuration file
 max_connections                | 300                                     | configuration file
 max_parallel_workers           | 2                                       | configuration file
 max_stack_depth                | 2MB                                     | environment variable
 max_wal_size                   | 2GB                                     | configuration file
 max_worker_processes           | 2                                       | configuration file
 min_wal_size                   | 256MB                                   | configuration file
 port                           | 5432                                    | configuration file
 random_page_cost               | 1.1                                     | configuration file
 shared_buffers                 | 2GB                                     | configuration file
 ssl                            | on                                      | configuration file
 ssl_cert_file                  | /etc/ssl/certs/ssl-cert-snakeoil.pem    | configuration file
 ssl_key_file                   | /etc/ssl/private/ssl-cert-snakeoil.key  | configuration file
 stats_temp_directory           | /var/run/postgresql/12-main.pg_stat_tmp | configuration file
 temp_buffers                   | 256MB                                   | configuration file
 TimeZone                       | Etc/UTC                                 | configuration file
 unix_socket_directories        | /var/run/postgresql                     | configuration file
 work_mem                       | 128MB                                   | configuration file
(37 Zeilen)

Operating system and version:
Linux dev 5.4.44-2-pve #1 SMP PVE 5.4.44-2 (Wed, 01 Jul 2020 16:37:57 +0200) x86_64 GNU/Linux

On a quad core virtualized machine with SSD storage and 16GB RAM.


What program you're using to connect to PostgreSQL:
psql and IntelliJ

I'm trying to gather as much information as possible and focus just on one of the two tables (the problem persists in both though):
-------------------------------------------------------------------------------------------------------

Stucture:

CREATE TABLE location_statistics
(
    daterange                daterange NOT NULL,
    spatial_feature_id           INTEGER,
    visitor_profile_id           INTEGER,
    activity_type_combination_id INTEGER,
    activity_chain_id            INTEGER NOT NULL,
    visitors                     REAL,
    dwell_time                   INTEGER,
    travel_time                  INTEGER,
    n                            INTEGER NOT NULL DEFAULT 1,

    PRIMARY KEY ( daterange, spatial_feature_id, visitor_profile_id, activity_type_combination_id,
                 activity_chain_id),
    FOREIGN KEY (daterange) REFERENCES dateranges (daterange) ON DELETE CASCADE ON UPDATE CASCADE,
    FOREIGN KEY (spatial_feature_id) REFERENCES spatial_features (id) ON DELETE CASCADE ON UPDATE CASCADE,
    FOREIGN KEY (visitor_profile_id) REFERENCES visitor_profiles (id) ON DELETE CASCADE ON UPDATE CASCADE,
    FOREIGN KEY (activity_type_combination_id) REFERENCES activity_type_combinations (id) ON DELETE RESTRICT ON UPDATE CASCADE,
    FOREIGN KEY (activity_chain_id) REFERENCES activity_chains (id) ON DELETE CASCADE ON UPDATE CASCADE
) PARTITION BY LIST (daterange);



-------------------------------------------------------------------------------------------------------

Creating of partitions:

CREATE OR REPLACE FUNCTION create_partition_tables(additional_dates TEXT[] = NULL)
    RETURNS VOID
    VOLATILE
    LANGUAGE plpgsql
AS
$$
DECLARE
    new_partition RECORD;
BEGIN

    FOR new_partition IN
        (
            SELECT for_values_str,
                   master_table,
                   partition_name
            FROM resolve_existing_partitions((additional_dates))
            WHERE NOT existing
        )
        LOOP

            EXECUTE ' CREATE TABLE '
                        || new_partition.partition_name
                        || ' PARTITION OF '
                        || new_partition.master_table
                        || ' FOR VALUES IN (' || new_partition.for_values_str || ')';

            RAISE NOTICE 'Partition % for % created',new_partition.partition_name, new_partition.master_table;
        END LOOP;
END
$$;

-------------------------------------------------------------------------------------------------------

Size of table:

SELECT schemaname,relname,n_live_tup
FROM pg_stat_user_tables
where relname like 'location_statistics_y2019m03%'
ORDER BY n_live_tup DESC;

schemaname	relname	n_live_tup
mobility_insights	location_statistics_y2019m03d	23569853
mobility_insights	location_statistics_y2019m03w	19264373
mobility_insights	location_statistics_y2019m03	18105295


-------------------------------------------------------------------------------------------------------



select * from pg_stats
where tablename = 'location_statistics_y2019m03w';

schemaname	tablename	attname	inherited	null_frac	avg_width	n_distinct	most_common_vals	most_common_freqs	histogram_bounds	correlation	most_common_elems	most_common_elem_freqs	elem_count_histogram
mobility_insights	location_statistics_y2019m03w	daterange	false	0	14	-1							
mobility_insights	location_statistics_y2019m03w	spatial_feature_id	false	0	4	600	{12675,7869,7867,7892,7915,7963,12677,12683,12237,7909,7868,9478,7914,11309,7913,7911,12509,9510,7962,10547,9559,10471,11782,10590,9552,10554,9527,10488,12680,9546,11330,11409,9595,12293,10845,11469,10531,10467,9525,7927,11115,10541,10544,9509,9515,10637,10486,10859,9703,9591,11195,11657,7878,7938,7910,9560,9565,9532,11016,12435,12525,9578,7973,9558,10536,12650,9516,9547,7871,10537,10923,10812,12546,9574,12454,9511,10435,11840,7926,12540,8187,10469,7935,9504,9536,11203,7964,9484,10534,10538,12391,10888,8237,9501,9517,12516,10927,11102,7985,10527}	{0.11813333630561829,0.06599999964237213,0.03723333403468132,0.031433332711458206,0.027033332735300064,0.023233333602547646,0.022333333268761635,0.0212333332747221,0.021166667342185974,0.02083333395421505,0.02033333294093609,0.0201666671782732,0.02006666734814644,0.019200000911951065,0.018833333626389503,0.01823333278298378,0.01510000042617321,0.014333332888782024,0.013633333146572113,0.013399999588727951,0.01146666705608368,0.011300000362098217,0.011233333498239517,0.011033332906663418,0.009666666388511658,0.009233333170413971,0.008433333598077297,0.007966666482388973,0.007966666482388973,0.007466666866093874,0.007300000172108412,0.007199999876320362,0.006566666532307863,0.006500000134110451,0.005799999926239252,0.00570000009611249,0.005166666582226753,0.004833333194255829,0.004766666796058416,0.004666666500270367,0.00423333328217268,0.0041333334520459175,0.004100000020116568,0.003966666758060455,0.0038333332631736994,0.0037666666321456432,0.003700000001117587,0.0035000001080334187,0.003433333244174719,0.0033666666131466627,0.0033333334140479565,0.003100000089034438,0.002933333395048976,0.00286666676402092,0.00283333333209157,0.00283333333209157,0.0026666666381061077,0.0024666667450219393,0.0024333333130925894,0.0024333333130925894,0.0024333333130925894,0.0023333332501351833,0.002266666619107127,0.002266666619107127,0.002266666619107127,0.002266666619107127,0.002233333420008421,0.002233333420008421,0.002199999988079071,0.002199999988079071,0.002199999988079071,0.002166666556149721,0.002166666556149721,0.002133333357051015,0.002099999925121665,0.0020666667260229588,0.0020666667260229588,0.0020666667260229588,0.002033333294093609,0.002033333294093609,0.0019333333475515246,0.0018666667165234685,0.0018333332845941186,0.0018333332845941186,0.0018333332845941186,0.0017999999690800905,0.0017666666535660625,0.0017666666535660625,0.0017666666535660625,0.0017666666535660625,0.0017666666535660625,0.0017333333380520344,0.0017000000225380063,0.0017000000225380063,0.0016666667070239782,0.0016333333915099502,0.0015999999595806003,0.0015999999595806003,0.001500000013038516,0.001500000013038516}	{7870,7891,7906,7917,7954,7965,7966,7969,7974,7977,7979,7984,7986,8132,8171,8194,9479,9482,9488,9491,9493,9496,9498,9499,9503,9507,9512,9513,9520,9521,9524,9526,9530,9534,9537,9541,9544,9554,9562,9570,9573,9577,9581,9583,9586,9599,9675,9736,10436,10442,10450,10464,10482,10491,10495,10510,10513,10515,10516,10523,10529,10535,10539,10543,10553,10575,10602,10718,10756,10816,10882,10902,10928,11008,11025,11064,11158,11276,11316,11382,11486,11538,11602,11673,11731,11766,11775,11835,11906,12052,12088,12130,12277,12356,12383,12397,12408,12471,12545,12627,12678}	0.11252771			
mobility_insights	location_statistics_y2019m03w	visitor_profile_id	false	0	4	9806	{3081,3114,2739,3642,2445,103,1625,1874,4005,2282,1550,3792,5564,750,1526,4427,2993,4881,1498,2682,5345,5601,8210,1613,2407,5019,1944,2266,3690,4529,4354,1218,11605,4126,5453,11698,11988,4207,6935,559,9151,12020,12048,12006,12049,3695,4874,5596,5945,6740,1366,7186,101,2026,5694,9152,4446,5788,8892,9365,11619,12027,871,5943,7567,7936,7939,8653,437,3971,5733,5961,7872,2728,3358,4154,4605,6187,9057,1967,4625,4837,5784,8910,1482,2036,6268,7557,8835,9,576,933,1686,2145,2229,3000,3692,4645,4666,5386}	{0.0024666667450219393,0.0023333332501351833,0.002300000051036477,0.002199999988079071,0.0020666667260229588,0.002033333294093609,0.002033333294093609,0.002033333294093609,0.0019666666630655527,0.0019333333475515246,0.0019000000320374966,0.0018666667165234685,0.0018666667165234685,0.0018333332845941186,0.0018333332845941186,0.0018333332845941186,0.0017999999690800905,0.0017333333380520344,0.0016333333915099502,0.0015999999595806003,0.0015666666440665722,0.0015666666440665722,0.0015666666440665722,0.0015333333285525441,0.001500000013038516,0.001466666697524488,0.00143333338201046,0.00143333338201046,0.00143333338201046,0.00143333338201046,0.00139999995008111,0.001366666634567082,0.001366666634567082,0.0013333333190530539,0.0013333333190530539,0.0013333333190530539,0.0013333333190530539,0.0012666666880249977,0.0012666666880249977,0.0012333333725109696,0.0012333333725109696,0.0012333333725109696,0.0012333333725109696,0.0012000000569969416,0.0012000000569969416,0.0011666666250675917,0.0011666666250675917,0.0011666666250675917,0.0011666666250675917,0.0011666666250675917,0.0011333333095535636,0.0011333333095535636,0.0010999999940395355,0.0010999999940395355,0.0010999999940395355,0.0010999999940395355,0.0010666666785255075,0.0010666666785255075,0.0010666666785255075,0.0010666666785255075,0.0010666666785255075,0.0010666666785255075,0.0010333333630114794,0.0010333333630114794,0.0010333333630114794,0.0010333333630114794,0.0010333333630114794,0.0010333333630114794,0.0010000000474974513,0.0010000000474974513,0.0010000000474974513,0.0010000000474974513,0.0010000000474974513,0.0009666666737757623,0.0009666666737757623,0.0009666666737757623,0.0009666666737757623,0.0009666666737757623,0.0009666666737757623,0.0009333333582617342,0.0009333333582617342,0.0009333333582617342,0.0009333333582617342,0.0009333333582617342,0.0008999999845400453,0.0008999999845400453,0.0008999999845400453,0.0008999999845400453,0.0008999999845400453,0.0008666666690260172,0.0008666666690260172,0.0008666666690260172,0.0008666666690260172,0.0008666666690260172,0.0008666666690260172,0.0008666666690260172,0.0008666666690260172,0.0008666666690260172,0.0008666666690260172,0.0008666666690260172}	{1,89,222,365,497,628,786,886,987,1108,1200,1320,1459,1584,1677,1812,1953,2080,2183,2306,2436,2581,2690,2798,2871,3018,3138,3294,3391,3525,3678,3783,3917,3992,4097,4253,4362,4442,4564,4693,4788,4897,5045,5157,5285,5414,5520,5630,5722,5843,5941,6041,6217,6444,6683,6892,7117,7330,7544,7730,7906,8076,8273,8471,8645,8789,8931,9063,9227,9378,9519,9610,9657,10667,10998,11483,11760,11960,12181,12262,12336,12440,12519,12629,13608,13782,13974,14116,14278,15670,16742,17892,18814,20657,23107,26119,31244,39466,59333,68728,83799}	-0.03462254			
mobility_insights	location_statistics_y2019m03w	activity_type_combination_id	false	0	4	145	{6,1,8,10,59,28,5,2,67,14,4,11,12,3,9,133,23,90,25,45,92,32,213,37,50,182,71,89,29,33,46,195,61,84,43,17,20,106,18,160,95,137,15,125,203,214,206,218,107,105,143,85,211,27,38,221,126,79,135,217,175,128,42,108,120,159,208,76,130}	{0.15360000729560852,0.14463333785533905,0.11789999902248383,0.06403333693742752,0.056533332914114,0.04636666551232338,0.035466667264699936,0.033533334732055664,0.02669999934732914,0.026133334264159203,0.023900000378489494,0.0203000009059906,0.019866665825247765,0.019233332946896553,0.01876666583120823,0.011966666206717491,0.01126666646450758,0.010066666640341282,0.009533333592116833,0.009499999694526196,0.00860000029206276,0.008366666734218597,0.0077666668221354485,0.00706666661426425,0.006899999920278788,0.006866666488349438,0.006599999964237213,0.006466666702181101,0.00566666666418314,0.004999999888241291,0.004533333238214254,0.004533333238214254,0.004333333112299442,0.0041333334520459175,0.004000000189989805,0.0033333334140479565,0.0031999999191612005,0.0031333332881331444,0.0025333333760499954,0.002166666556149721,0.0020666667260229588,0.0016333333915099502,0.0015333333285525441,0.00143333338201046,0.0013000000035390258,0.0013000000035390258,0.0012666666880249977,0.0012666666880249977,0.0011666666250675917,0.0010333333630114794,0.0010333333630114794,0.0009333333582617342,0.0009333333582617342,0.0007666666642762721,0.000733333348762244,0.000733333348762244,0.000699999975040555,0.0006666666595265269,0.0006666666595265269,0.0006666666595265269,0.0006333333440124989,0.0006000000284984708,0.0004666666791308671,0.0004666666791308671,0.0004666666791308671,0.0004333333345130086,0.0004333333345130086,0.000366666674381122,0.000366666674381122}	{22,26,36,54,54,54,64,64,70,77,87,88,96,97,98,98,101,112,114,114,118,119,127,127,131,138,145,148,148,151,151,153,153,155,155,155,163,164,164,165,166,169,169,170,170,173,176,180,184,187,187,187,194,194,201,201,201,219,227,227,228,231,231,232,233,233,251,256,272,274,286,303,303,315,324,490}	0.027344994			
mobility_insights	location_statistics_y2019m03w	activity_chain_id	false	0	4	75638	{5161,5206,5162,5184,5195,5323,5397,5815,6530,5216,7603,6545,5153,6332,6981,7432,5818,5415,5596,7121,7531,5359,5618,5967,6393,7884,14611,21593,355,5325,5986,6407,23475,5213,6039,6385,6621,6849,9910,10026,11114,15860,164,165,200,5165,5262,5890,6043,6231,6659,6950,7251,7284,8228,8456,8923,9212,9851,9886,12203,12983,14685,16472,21550,43,271,307,992,5220,5243,5481,5482,5509,5516,5532,5603,5621,5757,5917,6026,6063,6139,6146,6210,6214,6464,6499,6671,6728,6758,6889,7010,7173,7643,8032,8081,8290,9676,10875}	{0.002133333357051015,0.0017999999690800905,0.00143333338201046,0.0011333333095535636,0.0010333333630114794,0.000699999975040555,0.000699999975040555,0.000699999975040555,0.0006666666595265269,0.0006333333440124989,0.0006333333440124989,0.0005000000237487257,0.0004666666791308671,0.0004666666791308671,0.0004666666791308671,0.0004666666791308671,0.0004333333345130086,0.000366666674381122,0.000366666674381122,0.000366666674381122,0.000366666674381122,0.00033333332976326346,0.00033333332976326346,0.00033333332976326346,0.00033333332976326346,0.00033333332976326346,0.00033333332976326346,0.00033333332976326346,0.0003000000142492354,0.0003000000142492354,0.0003000000142492354,0.0003000000142492354,0.0003000000142492354,0.00026666666963137686,0.00026666666963137686,0.00026666666963137686,0.00026666666963137686,0.00026666666963137686,0.00026666666963137686,0.00026666666963137686,0.00026666666963137686,0.00026666666963137686,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503}	{16,3832,5935,6980,8254,9534,11187,13024,15280,17910,20278,23752,27191,30933,35166,39736,44912,84588,87937,91731,96462,98710,99978,101481,102822,104232,105743,107178,108599,109896,111309,112882,114244,115636,117258,118951,120523,122033,123500,124882,126475,127916,129472,131137,132751,134476,135966,137506,139103,140651,142235,143923,145489,147256,148803,150223,151772,153331,155019,156745,158504,160131,161734,163321,164954,166505,168223,169899,171482,173009,174615,176117,177796,179595,181180,182924,184591,186335,188152,189909,191799,193278,194998,196949,198845,200761,202607,204272,206366,208030,209664,211457,213181,214854,216416,218122,219912,221852,223592,225495,227061}	-0.13226064			
mobility_insights	location_statistics_y2019m03w	visitors	false	0	4	141556	{2.231728,2.515927,1.690992,2.716124,1.666667,4.006526,4.547657,2.685691,2.042206,2.0369,2.907664,3.202489,3.321924,5,2.21855,0.357143,1.781995,2.773392,2.430318,3.585561,0.251593,0.294118,0.333333,0.416667,0.47619,1.997838,2.901269,3.665649,0.083864,0.166667,0.228721,0.278577,0.284229,0.3125,0.375056,0.833333,2.434593,2.616505,2.744186,2.95092,3.26703,3.7,3.959243}	{0.0008999999845400453,0.0007999999797903001,0.0006333333440124989,0.0005666666547767818,0.0005333333392627537,0.0005333333392627537,0.0005333333392627537,0.0005000000237487257,0.0004333333345130086,0.00039999998989515007,0.00039999998989515007,0.000366666674381122,0.000366666674381122,0.000366666674381122,0.00033333332976326346,0.0003000000142492354,0.0003000000142492354,0.0003000000142492354,0.00026666666963137686,0.00026666666963137686,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503,0.00019999999494757503}	{2e-06,0.00196,0.003629,0.00529,0.00717,0.00941,0.011622,0.013755,0.016387,0.019173,0.022388,0.02522,0.028369,0.031243,0.03431,0.037177,0.04011,0.043427,0.046591,0.04976,0.052685,0.05561,0.058774333,0.061956,0.065245,0.068608,0.072032,0.0754775,0.078632,0.081756,0.084959,0.088382,0.091822,0.095209,0.098459,0.102495,0.106105,0.109757,0.113244,0.116785,0.120467,0.124337,0.128564,0.132854,0.136804,0.140986,0.145268,0.149572,0.153727,0.157896,0.162,0.166096,0.170477,0.174326,0.178639,0.182968,0.187422,0.191749,0.19638,0.200433,0.205387,0.209918,0.214573,0.218993,0.224327,0.229155,0.234454,0.239658,0.244123,0.249223,0.254667,0.260309,0.265922,0.271871,0.277339,0.283247,0.289332,0.296549,0.303343,0.309744,0.317473,0.325838,0.335268,0.344108,0.352898,0.363003,0.3743145,0.387081,0.401563,0.420192,0.440096,0.461973,0.490929,0.528797,0.574014,0.652174,0.7746,1.056453,1.79342,2.771285,14.935622}	0.010959746			
mobility_insights	location_statistics_y2019m03w	dwell_time	false	0	4	45441	{84600,82800,3600,4500,5400,8100,22500,24300,19800,85499,6300,7200,20700,23400,28800,3722,9000,15300,21600,10800,9900,10802,17100,79200,85500,11700,13500,14400,18900,25200,12600,16200,18000,83700,900,3672,3785,3885,5395,5803,5882,7227,27000,27900,43200,80100}	{0.002199999988079071,0.0010000000474974513,0.0008333333535119891,0.0007999999797903001,0.0006666666595265269,0.0006000000284984708,0.0006000000284984708,0.0006000000284984708,0.0005666666547767818,0.0005666666547767818,0.0004666666791308671,0.0004666666791308671,0.0004666666791308671,0.0004666666791308671,0.0004666666791308671,0.00039999998989515007,0.00039999998989515007,0.00039999998989515007,0.00039999998989515007,0.000366666674381122,0.00033333332976326346,0.00033333332976326346,0.00033333332976326346,0.00033333332976326346,0.00033333332976326346,0.0003000000142492354,0.0003000000142492354,0.0003000000142492354,0.0003000000142492354,0.0003000000142492354,0.00026666666963137686,0.00026666666963137686,0.00026666666963137686,0.00026666666963137686,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356}	{901,2191,3633,3768,3915,4052,4205,4339,4491,4656,4827,5001,5185,5397,5634,5858,6082,6301,6551,6807,7083,7382,7726,8047,8396,8763,9194,9619,9983,10422,10807,11222,11641,12068,12558,13041,13493,13974,14398,14902,15401,15892,16457,16919,17431,17930,18442,18975,19508,20077,20672,21238,21709,22227,22779,23430,24002,24556,25239,26011,26758,27547,28312,29178,29973,30780,31617,32484,33460,34584,35745,36979,38294,39664,41203,42960,44652,46476,48492,50223,52200,54421,56359,58815,61658,64739,67538,70443,73060,75490,77594,79466,80991,82197,83188,83999,84836,85406,85738,86091,86400}	-0.066642396			
mobility_insights	location_statistics_y2019m03w	travel_time	false	0	4	11756	{0,5,2700,900,3600,1800,3599,10,425,810,1680,2245}	{0.5346666574478149,0.0006666666595265269,0.0005000000237487257,0.0004666666791308671,0.00039999998989515007,0.000366666674381122,0.00026666666963137686,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356,0.00023333333956543356}	{2,139,279,423,551,648,752,852,937,1024,1112,1195,1286,1375,1451,1540,1631,1760,1861,1958,2058,2162,2264,2367,2470,2575,2683,2805,2912,3013,3146,3270,3373,3513,3604,3709,3824,3951,4067,4205,4328,4437,4532,4681,4841,5002,5147,5291,5452,5602,5763,5924,6060,6223,6390,6554,6719,6917,7109,7294,7490,7698,7904,8095,8299,8537,8724,8982,9242,9536,9775,10066,10363,10632,10933,11273,11643,12014,12368,12776,13176,13580,14021,14450,14922,15462,15934,16468,17097,17693,18538,19456,20254,21245,22403,23780,25470,27648,31072,36178,62080}	0.31811374			
mobility_insights	location_statistics_y2019m03w	n	false	0	4	7	{1,2,3,4,5,6,7}	{0.9218999743461609,0.04879999905824661,0.014600000344216824,0.0075333332642912865,0.0038666666951030493,0.0026000000070780516,0.000699999975040555}		0.85469824			

-------------------------------------------------------------------------------------------------------

Query:
EXPLAIN ( ANALYZE , BUFFERS )
SELECT sum(visitors * n)
FROM location_statistics st
WHERE st.daterange = '[2019-03-04,2019-03-11)'::DATERANGE
  AND spatial_feature_id = 12675
QUERY PLAN
Aggregate  (cost=2.79..2.80 rows=1 width=8) (actual time=143.073..143.073 rows=1 loops=1)
  Buffers: shared hit=67334
  ->  Index Scan using location_statistics_y2019m03w_pkey on location_statistics_y2019m03w st  (cost=0.56..2.78 rows=1 width=8) (actual time=0.026..117.284 rows=516277 loops=1)
        Index Cond: ((daterange = '[2019-03-04,2019-03-11)'::daterange) AND (spatial_feature_id = 12675))
        Buffers: shared hit=67334
Planning Time: 0.082 ms
Execution Time: 143.095 ms


For completeness sake:

EXPLAIN (ANALYZE , BUFFERS)
SELECT sum(visitors * n)
FROM location_statistics_y2019m03w st
WHERE st.daterange = '[2019-03-04,2019-03-11)'::DATERANGE
  AND spatial_feature_id = 12675
QUERY PLAN
Aggregate  (cost=2.79..2.80 rows=1 width=8) (actual time=156.304..156.305 rows=1 loops=1)
  Buffers: shared hit=66602 read=732
  ->  Index Scan using location_statistics_y2019m03w_pkey on location_statistics_y2019m03w st  (cost=0.56..2.78 rows=1 width=8) (actual time=0.194..111.464 rows=516277 loops=1)
        Index Cond: ((daterange = '[2019-03-04,2019-03-11)'::daterange) AND (spatial_feature_id = 12675))
        Buffers: shared hit=66602 read=732
Planning Time: 0.058 ms
Execution Time: 156.326 ms


As can be seen, the planner predicts one row to be returned, although it should be around 3% (11% of the entries are of the given ID, which are distributed over 4 weeks = date ranges) of the table. Using the partition table directly, does not change this fact.

How can I solve this problem?

Thank you very much in advance.