Streaming table reads
To read an entire table snapshot, use the read subcommand. Data is transferred as a stream, which enables you to read any size table.
Read data:
ydb table read episodes \
--ordered \
--limit 5 \
--columns series_id,season_id,episode_id,title
Where:
--ordered: Order read entries by key.--limit: Limit the number of entries to read.--columns: Columns whose values should be read (all by default) in CSV format.
Result:
┌───────────┬───────────┬────────────┬───────────────────────────────┐
| series_id | season_id | episode_id | title |
├───────────┼───────────┼────────────┼───────────────────────────────┤
| 1 | 1 | 1 | "Yesterday's Jam" |
├───────────┼───────────┼────────────┼───────────────────────────────┤
| 1 | 1 | 2 | "Calamity Jen" |
├───────────┼───────────┼────────────┼───────────────────────────────┤
| 1 | 1 | 3 | "Fifty-Fifty" |
├───────────┼───────────┼────────────┼───────────────────────────────┤
| 1 | 1 | 4 | "The Red Door" |
├───────────┼───────────┼────────────┼───────────────────────────────┤
| 1 | 1 | 5 | "The Haunting of Bill Crouse" |
└───────────┴───────────┴────────────┴───────────────────────────────┘
To only get the number of read entries, use the --count-only parameter:
ydb table read episodes \
--columns series_id \
--count-only
Result:
70