Personal information indexing for columnar data storage format

One or more non-transitory computer-readable media storing instructions which, when executed by one or more processors, cause:

• storing in a set of files a plurality row groups of rows that comprise a plurality of columns, wherein for each row group, each column of said plurality of columns is stored in a respective chunk of column pages in the set of files;
• for each row group of said plurality of row groups:
• generating a respective regular expression index that indexes a particular column, determining whether the size of the respective regular expression index is below a threshold, and storing in the set of files said respective regular expression index based on the determination, wherein said regular expression index identifies one or more column pages in the respective chunk of said particular column and said each row group that include a particular column value that satisfies a regular expression.