Cassandra

Command can be run on the Cassandra Web at localhost:3000 or in the docker container with:

sudo docker exec -it cass1 cqlsh

Note the MATERIALZIED VIEWS and CUSTOM INDEX are already created in the startup script and don't needed to be run again.

Queries

All queries can also be found here.

1. Listing all the posts made by an account.

    SELECT content FROM twitter.tweets where author_id = 233248636;
   

2. Find the 100 accounts with the most followers

# 2. Find the 100 accounts with the most followers
rows = session.execute('SELECT user_id,follower_len FROM twitter.most_follows;')
sorted_rows = dict(sorted(dict(rows).items(), key=lambda item: item[1]))
most_follows = list(sorted_rows.keys())[-100:]
print("Top 100 most followed accounts:",most_follows)

Top 100 most followed accounts: [817268, 173732041, 14506809, 158804228, 358775055, 45416789, 302282272, 65913144, 261001122, 14246001, 7702232, 101204352, 280365428, 15439395, 26929220, 46537966, 32774989, 2367911, 7429892, 88097807, 274153775, 41147062, 127973392, 10350, 12127832, 18666844, 279787626, 14511951, 116036694, 225784456, 270449528, 63796828, 22784458, 364917755, 15693493, 17346342, 28933226, 7872262, 14180231, 100581193, 88323281, 131029775, 25952851, 14692604, 21681252, 309366491, 25376226, 22705686, 188108667, 18715024, 3829151, 41172837, 92319025, 24081780, 15102849, 83943787, 15680204, 7846, 184097849, 7377812, 204317520, 24641194, 14691709, 112939321, 7081402, 153226312, 14269220, 94414805, 108811740, 1065921, 221829166, 116952434, 15222083, 6608332, 17759701, 16098603, 7860742, 20471349, 6519522, 19040580, 14536491, 197504076, 12611642, 36198161, 3840, 22841103, 440963134, 20273398, 17092592, 13348, 17093617, 22679419, 208132323, 18776017, 15846407, 18581803, 5442012, 813286, 3359851, 59804598]

3. Finding the 100 accounts that follow the most of the accounts found in 2).

followed_accs = session.execute(f'SELECT follower_id FROM twitter.follower_relation WHERE user_id IN {tuple(most_follows)};')
_list = list()
for row in followed_accs:
    _list.append(row[0])

followed_top_100 = Counter(_list).most_common(100)
print("100 accounts that follow the most of the accounts found in 2)",followed_top_100)

100 accounts that follow the most of the accounts found in 2) [(3359851, 47), (7860742, 47), (15913, 45), (7861312, 45), (16098603, 43), (18776017, 41), (10350, 39), (48485771, 39), (22679419, 38), (3443591, 37), (18581803, 37), (18927441, 37), (26281970, 37), (7872262, 36), (24742040, 36), (5442012, 36), (10671602, 35), (11928542, 35), (14922225, 35), (16453996, 35), (21681252, 35), (14589257, 34), (15853668, 34), (9451052, 34), (65913144, 34), (14269220, 34), (15234657, 34), (17092592, 34), (59804598, 34), (87764480, 34), (40981798, 34), (16475194, 34), (16464746, 33), (93905958, 33), (20152005, 33), (42361118, 33), (36629388, 33), (18666844, 32), (19413393, 32), (12127832, 32), (14180231, 32), (14983833, 32), (25026165, 32), (18742444, 32), (29758446, 31), (20880546, 31), (116952434, 31), (30207757, 31), (21195122, 31), (43003845, 31), (22784458, 30), (19040580, 30), (14691709, 30), (24004172, 30), (1065921, 30), (26280712, 30), (43170475, 30), (22462180, 30), (7846, 29), (1183041, 29), (3040621, 29), (7377812, 29), (34428380, 29), (20273398, 28), (14230524, 28), (15222083, 28), (24641194, 28), (83943787, 28), (36198161, 28), (14536491, 28), (813286, 27), (12611642, 27), (29514951, 27), (31353077, 27), (18996905, 27), (14471778, 27), (15838599, 27), (16112634, 27), (17526132, 27), (17759701, 27), (31331740, 27), (25952851, 27), (84043660, 27), (9431932, 27), (20397258, 27), (127973392, 27), (16674726, 27), (116036694, 27), (972651, 26), (13687132, 26), (4068821, 26), (7702232, 26), (6080022, 26), (17224642, 26), (20935355, 26), (24081780, 26), (26033920, 26), (28933226, 26), (43933017, 26), (101633415, 26)]

4. Listing the information for the personal home page of any account (best try with the accounts found in 2); the start page should contain the following (implement as separate queries):

   • the number of followers && the number of followed accounts

     SELECT follower_len, follows_len FROM twitter.user_stats WHERE user_id = 233248636; //cheack user_id can be changed

     

   • either the 25 newest or the 25 most popular posts of the followed accounts (via DB query)

     25 newest

     CREATE MATERIALIZED VIEW twitter.start_view_new AS
       SELECT user_id_x,follower_id,number_of_likes,number_of_shares,date_time,name,author,content,id FROM twitter.user
       WHERE user_id_x IS NOT NULL AND follower_id IS NOT NULL AND date_time IS NOT NULL AND id IS NOT NULL
       PRIMARY KEY ((user_id_x),date_time,follower_id,id);
     
     SELECT * FROM twitter.start_view_new WHERE user_id_x = 172883064 ORDER BY date_time DESC LIMIT 25;
     

   

   25 most popular
   
      CREATE MATERIALIZED VIEW twitter.start_view_like AS
       SELECT user_id_x,follower_id,number_of_likes,number_of_shares,date_time,author,name,content,id FROM twitter.user
       WHERE user_id_x IS NOT NULL AND follower_id IS NOT NULL AND number_of_likes IS NOT NULL AND id IS NOT NULL
       PRIMARY KEY ((user_id_x),number_of_likes,follower_id,id);
   
      SELECT * FROM twitter.start_view_like WHERE user_id_x = 172883064 ORDER BY number_of_likes DESC LIMIT 25; 
   

   

5. Caching of the posts for the home page (cf. 4) requires a so-called fan-out in the cache of each follower when writing a new post

    CREATE MATERIALIZED VIEW twitter.start_view_user1 AS
     SELECT follower_id,number_of_likes,date_time,author,name,content,id FROM twitter.user 
     WHERE user_id_x IS NOT NULL AND user_id_x=172883064 AND follower_id IS NOT NULL AND number_of_likes IS NOT NULL AND id IS NOT NULL 
     PRIMARY KEY ((user_id_x),number_of_likes,follower_id,id);
    // # order by need partion key in WHERE
    SELECT * from twitter.start_view_taylor WHERE user_id_x=172883064 ORDER BY number_of_likes DESC LIMIT 25;
    // INSERT new tweet
    INSERT INTO twitter.user
    (user_id_x,follower_id,name,author ,content ,country ,date_time ,id ,language ,latitude ,longitude ,number_of_likes ,number_of_shares ,user_id_y)
    VALUES
    (172883064, 233248636, 'NoName','taylorswift12', 'Hallo there BDEA','DE', dateof(now()), 'NoID', 'de', 48, 48, 10000000, 0, 0);
   
    INSERT INTO twitter.tweets(author, content, country, date_time, id, language, latitude, longitude, number_of_likes, number_of_shares ,author_id)
    VALUES
    ('taylorswift12', 'Hallo there BDEA','DE', dateof(now()), 'NoID', 'de', 48, 48, 10000000, 0, 0 '233248636');
   

   

6. List of the 25 most popular posts that contain a given word (if possible also with AND linking several words)

    // To order by the 25 most number_of_like is at our knowledge not possible with the current dataschema
    CREATE CUSTOM INDEX search_in ON twitter.tweets (content) USING 'org.apache.cassandra.index.sasi.SASIIndex'
      WITH OPTIONS = {  'mode': 'CONTAINS', 'analyzer_class': 'org.apache.cassandra.index.sasi.analyzer.NonTokenizingAnalyzer',
      'case_sensitive': 'false' };
    SELECT * from twitter.tweets WHERE content LIKE '%world%' limit 25;