The correct answer is A. The statements will load the data only once in the table .
By default, Snowflake tracks metadata for files that have already been loaded into a table. This load metadata helps prevent the same staged file from being loaded again into the same table when using the default COPY INTO < table > behavior.
Why A is correct:
Snowflake's default copy behavior prevents duplicate loading of the same file into the same table. Even if multiple identical COPY INTO statements run against the same file, Snowflake uses load metadata to avoid loading the same file multiple times.
Important default behavior:
The default value of FORCE is FALSE. This means Snowflake does not reload files that have already been loaded successfully into the table.
Why the other options are incorrect:
B). Data is not duplicated under the default settings because Snowflake tracks loaded files.
C). Running parallel copy statements does not automatically fail just because they reference the same file.
D). COPY INTO < table > does not overwrite table data by default. It appends loaded rows, but duplicate file loading is prevented by load metadata.
Official Snowflake documentation reference:
Snowflake documentation explains that Snowflake maintains load metadata for tables and prevents reloading the same files by default unless FORCE = TRUE is specified.
Reference: Snowflake Documentation - COPY INTO < table > ; Snowflake Documentation - Load metadata; Snowflake Documentation - FORCE copy option; SnowPro Core Study Guide - Data Loading and Unloading.
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Best practices for loading data into Snowflake include aiming for data file sizes between 100 MB and 250 MB when compressed, as this size is optimal for parallel processing and minimizes overhead. Enclosing fields with delimiter characters in quotes ensures proper field recognition during the load process. Splitting large files into smaller ones allows for better distribution of the load across compute resources, enhancing performance and efficiency.

Federated authentication in Snowflake allows users to use their organizational credentials to log in to Snowflake, leveraging Single Sign-On (SSO). The key activities enabled by this setup include:
B). Initiating user sessions: Federated authentication streamlines the process of starting a user session in Snowflake by using the existing authentication mechanisms of an organization.
C). Logging into Snowflake: It simplifies the login process, allowing users to authenticate with their organization ' s identity provider instead of managing separate credentials for Snowflake.
References:
Snowflake Documentation: Configuring Federated Authentication