Look at the sources: fast-parquet-row-count-in-spark and parquet-count-metadata-explanation
Stackoverflow and official spark documentation tells us that parquet file should contains row count in metadata. And spark added this by default since 1.6
I tried to see this "field" but have no luck. May be I am doing something wrong? Could somebody tell me how ensure that some parquet file has such filed? Any link to small but good parquet file welcome! For now I am invoking org.apache.parquet.tools.Main with arguments meta D:\myparquet_file.parquet and see no count key word in results.
CodePudding user response：
You can inspect a parquet file using parquet-tools:
- Install
parquet-tools:
pip install parquet-tools
- Create a parquet file. I used spark to create a small parquet file with 3 rows:
import spark.implicits._
val df: DataFrame = Seq((1, 2, 3), (4, 5, 6), (7, 8, 9)).toDF("col1", "col2", "col3")
df.coalesce(1).write.parquet("data/")
- inspect the parquet file:
parquet-tools inspect /path/to/parquet/file
The output should be something like:
############ file meta data ############
created_by: parquet-mr version 1.10.1 (build a89df8f9932b6ef6633d06069e50c9b7970bebd1)
num_columns: 3
num_rows: 3
num_row_groups: 1
format_version: 1.0
serialized_size: 654
############ Columns ############
col1
col2
col3
############ Column(col1) ############
name: col1
path: col1
max_definition_level: 0
max_repetition_level: 0
physical_type: INT32
logical_type: None
converted_type (legacy): NONE
############ Column(col2) ############
name: col2
path: col2
max_definition_level: 0
max_repetition_level: 0
physical_type: INT32
logical_type: None
converted_type (legacy): NONE
############ Column(col3) ############
name: col3
path: col3
max_definition_level: 0
max_repetition_level: 0
physical_type: INT32
logical_type: None
converted_type (legacy): NONE
You can see under the file meta data section the num_rows field that represent the number of rows in the parquet file.
CodePudding user response：
You can find the row count in the field RC just beside the row group.
row group 1: RC:148192 TS:10503944 OFFSET:4
Full output of parquet-tool with meta option below.
> parquet-tools meta part-00000-fc34f237-c985-4ebc-822b-87fa446f6f70.c000.snappy.parquet
file: file:/Users/matthewropp/team_demo/los-angeles-parking-citations/raw_citations/issue_month=201902/part-00000-fc34f237-c985-4ebc-822b-87fa446f6f70.c000.snappy.parquet
creator: parquet-mr version 1.10.0 (build 031a6654009e3b82020012a18434c582bd74c73a)
extra: org.apache.spark.sql.parquet.row.metadata = {"type":"struct","fields":[{"name":":created_at","type":"string","nullable":true,"metadata":{}},{"name":":id","type":"string","nullable":true,"metadata":{}},{"name":":updated_at","type":"string","nullable":true,"metadata":{}},{"name":"agency","type":"integer","nullable":true,"metadata":{}},{"name":"body_style","type":"string","nullable":true,"metadata":{}},{"name":"color","type":"string","nullable":true,"metadata":{}},{"name":"fine_amount","type":"integer","nullable":true,"metadata":{}},{"name":"issue_date","type":"date","nullable":true,"metadata":{}},{"name":"issue_time","type":"integer","nullable":true,"metadata":{}},{"name":"latitude","type":"decimal(8,1)","nullable":true,"metadata":{}},{"name":"location","type":"string","nullable":true,"metadata":{}},{"name":"longitude","type":"decimal(8,1)","nullable":true,"metadata":{}},{"name":"make","type":"string","nullable":true,"metadata":{}},{"name":"marked_time","type":"string","nullable":true,"metadata":{}},{"name":"meter_id","type":"string","nullable":true,"metadata":{}},{"name":"plate_expiry_date","type":"date","nullable":true,"metadata":{}},{"name":"route","type":"string","nullable":true,"metadata":{}},{"name":"rp_state_plate","type":"string","nullable":true,"metadata":{}},{"name":"ticket_number","type":"string","nullable":false,"metadata":{}},{"name":"vin","type":"string","nullable":true,"metadata":{}},{"name":"violation_code","type":"string","nullable":true,"metadata":{}},{"name":"violation_description","type":"string","nullable":true,"metadata":{}}]}
file schema: spark_schema
--------------------------------------------------------------------------------
: created_at: OPTIONAL BINARY O:UTF8 R:0 D:1
: id: OPTIONAL BINARY O:UTF8 R:0 D:1
: updated_at: OPTIONAL BINARY O:UTF8 R:0 D:1
agency: OPTIONAL INT32 R:0 D:1
body_style: OPTIONAL BINARY O:UTF8 R:0 D:1
color: OPTIONAL BINARY O:UTF8 R:0 D:1
fine_amount: OPTIONAL INT32 R:0 D:1
issue_date: OPTIONAL INT32 O:DATE R:0 D:1
issue_time: OPTIONAL INT32 R:0 D:1
latitude: OPTIONAL INT32 O:DECIMAL R:0 D:1
location: OPTIONAL BINARY O:UTF8 R:0 D:1
longitude: OPTIONAL INT32 O:DECIMAL R:0 D:1
make: OPTIONAL BINARY O:UTF8 R:0 D:1
marked_time: OPTIONAL BINARY O:UTF8 R:0 D:1
meter_id: OPTIONAL BINARY O:UTF8 R:0 D:1
plate_expiry_date: OPTIONAL INT32 O:DATE R:0 D:1
route: OPTIONAL BINARY O:UTF8 R:0 D:1
rp_state_plate: OPTIONAL BINARY O:UTF8 R:0 D:1
ticket_number: REQUIRED BINARY O:UTF8 R:0 D:0
vin: OPTIONAL BINARY O:UTF8 R:0 D:1
violation_code: OPTIONAL BINARY O:UTF8 R:0 D:1
violation_description: OPTIONAL BINARY O:UTF8 R:0 D:1
row group 1: RC:148192 TS:10503944 OFFSET:4
--------------------------------------------------------------------------------
: created_at: BINARY SNAPPY DO:0 FPO:4 SZ:607/616/1.01 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: 2019-02-28T00:16:06.329Z, max: 2019-03-02T00:20:00.249Z, num_nulls: 0]
: id: BINARY SNAPPY DO:0 FPO:611 SZ:2365472/3260525/1.38 VC:148192 ENC:BIT_PACKED,PLAIN,RLE ST:[min: row-2229_y75z.ftdu, max: row-zzzs_4hta.8fub, num_nulls: 0]
: updated_at: BINARY SNAPPY DO:0 FPO:2366083 SZ:602/611/1.01 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: 2019-02-28T00:16:06.329Z, max: 2019-03-02T00:20:00.249Z, num_nulls: 0]
agency: INT32 SNAPPY DO:0 FPO:2366685 SZ:4871/5267/1.08 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: 1, max: 58, num_nulls: 0]
body_style: BINARY SNAPPY DO:0 FPO:2371556 SZ:36244/61827/1.71 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: , max: WR, num_nulls: 0]
color: BINARY SNAPPY DO:0 FPO:2407800 SZ:111267/111708/1.00 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: , max: YL, num_nulls: 0]
fine_amount: INT32 SNAPPY DO:0 FPO:2519067 SZ:71989/82138/1.14 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: 25, max: 363, num_nulls: 63]
issue_date: INT32 SNAPPY DO:0 FPO:2591056 SZ:20872/23185/1.11 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: 2019-02-01, max: 2019-02-27, num_nulls: 0]
issue_time: INT32 SNAPPY DO:0 FPO:2611928 SZ:210026/210013/1.00 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: 1, max: 2359, num_nulls: 41]
latitude: INT32 SNAPPY DO:0 FPO:2821954 SZ:508049/512228/1.01 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: 99999.0, max: 6513161.2, num_nulls: 0]
location: BINARY SNAPPY DO:0 FPO:3330003 SZ:1251364/2693435/2.15 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,PLAIN,RLE ST:[min: , max: ZOMBAR/VALERIO, num_nulls: 0]
longitude: INT32 SNAPPY DO:0 FPO:4581367 SZ:516233/520692/1.01 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: 99999.0, max: 1941557.4, num_nulls: 0]
make: BINARY SNAPPY DO:0 FPO:5097600 SZ:147034/150364/1.02 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: , max: YAMA, num_nulls: 0]
marked_time: BINARY SNAPPY DO:0 FPO:5244634 SZ:11675/17658/1.51 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: , max: 959.0, num_nulls: 0]
meter_id: BINARY SNAPPY DO:0 FPO:5256309 SZ:172432/256692/1.49 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: , max: YO97, num_nulls: 0]
plate_expiry_date: INT32 SNAPPY DO:0 FPO:5428741 SZ:149849/152288/1.02 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: 2000-02-01, max: 2099-12-01, num_nulls: 18624]
route: BINARY SNAPPY DO:0 FPO:5578590 SZ:38377/45948/1.20 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: , max: WTD, num_nulls: 0]
rp_state_plate: BINARY SNAPPY DO:0 FPO:5616967 SZ:33281/60186/1.81 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: AB, max: XX, num_nulls: 0]
ticket_number: BINARY SNAPPY DO:0 FPO:5650248 SZ:801039/2074791/2.59 VC:148192 ENC:BIT_PACKED,PLAIN ST:[min: 1020798376, max: 4350802142, num_nulls: 0]
vin: BINARY SNAPPY DO:0 FPO:6451287 SZ:64/60/0.94 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: , max: , num_nulls: 0]
violation_code: BINARY SNAPPY DO:0 FPO:6451351 SZ:94784/131071/1.38 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: 000, max: 8942, num_nulls: 0]
violation_description: BINARY SNAPPY DO:0 FPO:6546135 SZ:95937/132641/1.38 VC:148192 ENC:BIT_PACKED,PLAIN_DICTIONARY,RLE ST:[min: , max: YELLOW ZONE, num_nulls: 0]
> parquet-tools dump -m -c make part-00000-fc34f237-c985-4ebc-822b-87fa446f6f70.c000.snappy.parquet | head -20
BINARY make
--------------------------------------------------------------------------------
*** row group 1 of 1, values 1 to 148192 ***
value 1: R:0 D:1 V:HYDA
value 2: R:0 D:1 V:NISS
value 3: R:0 D:1 V:NISS
value 4: R:0 D:1 V:TOYO
value 5: R:0 D:1 V:AUDI
value 6: R:0 D:1 V:MERC
value 7: R:0 D:1 V:LEX
value 8: R:0 D:1 V:BMW
value 9: R:0 D:1 V:GMC
value 10: R:0 D:1 V:HOND
value 11: R:0 D:1 V:TOYO
value 12: R:0 D:1 V:NISS
value 13: R:0 D:1 V:
value 14: R:0 D:1 V:THOR
value 15: R:0 D:1 V:DODG
value 16: R:0 D:1 V:DODG
value 17: R:0 D:1 V:HOND