perf(table): import the expression parser lazily - #4012
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The parser is only used by _parse_row_filter for string row filters, but importing it at module level pulls in pyparsing (and unittest, argparse and difflib through pyparsing.testing) on every `import pyiceberg.table` and `load_catalog`.
Fokko
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Sep 24, 2026
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Reasonable change, thanks @kuldeeepy
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Rationale for this change
pyiceberg.tableimportspyiceberg.expressions.parserat module level, but only_parse_row_filteruses it, when the row filter is a string. Importing it pulls in pyparsing, and throughpyparsing.testingalso unittest, argparse and difflib. So everyimport pyiceberg.tableandload_catalogpays for it, even when no string filter is used.This moves the import into
_parse_row_filter, the same way the file already importsArrowScanlocally. After the change pyparsing is no longer loaded byfrom pyiceberg.catalog import load_catalog, and the number of loaded modules goes from 389 to 361. On my machine that import takes about 6% less CPU time.Are these changes tested?
Covered by the existing parser and row filter tests.
make lintandmake testpass.Are there any user-facing changes?
No.
This change was made with AI assistance (Claude Code). I checked the import paths and ran the measurements and tests myself.