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perf: JIRA-17851 stream export rows instead of holding them in memory - #118
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filterQuery() built every row of an export into one array and returned it, and normalizeOptionalItems() then made a second full pass over that array to fill in the optional columns. Memory grew with the size of the export, and exports around 100,000 rows were exhausting a 2 GB process limit even after the generator had been made to stream. Rows are now written to a buffer as they are built. The buffer lives in memory up to 8 MB and spills to a temp file beyond that, and it tracks the fixed and optional column names as rows arrive. Reading it back fills each row out to the final column list, so the optional-column behaviour is unchanged: optional columns follow the fixed ones in the order first seen, an optional value takes precedence over a fixed column of the same name, and a row without a value gets an empty string. The CSV writer consumes the rows one at a time and takes the header from the column list, so nothing holds the whole export at once. Measured on 50,000 rows: memory growth stays under 24 MB where it was previously proportional to the row count, and a three-chunk export no longer grows between chunks. BREAKING CHANGE: filterQuery() returns a RowStream rather than an array, and ProcessorData accepts any iterable of rows. ProcessorData gains rows(), getColumns() and getCount(); getData() still returns an array but now loads every row to do so, and should not be used for large exports. getAllOptionalKeys() and normalizeOptionalItems() are removed; their behaviour lives in RowStream. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
📝 WalkthroughWalkthroughThe export pipeline now supports iterable and disk-backed row processing. ChangesStreaming export pipeline
Estimated code review effort: 4 (Complex) | ~45 minutes Merge Risk: 🟡 Moderate · up to A temporary-stream write failure can produce an incomplete export whose reported row count is incorrect. This should be fixed before merge. Sequence Diagram(s)sequenceDiagram
participant EloquentProcessor
participant RowStream
participant ProcessorData
participant CsvDriver
EloquentProcessor->>RowStream: push processed rows
RowStream-->>ProcessorData: provide columns, count, and rows
ProcessorData-->>CsvDriver: expose export data
CsvDriver->>RowStream: iterate normalized rows
RowStream-->>CsvDriver: return CSV row values
🚥 Pre-merge checks | ✅ 4 | ❌ 1❌ Failed checks (1 warning)
✅ Passed checks (4 passed)
✨ Finishing Touches 💡 1📝 Generate docstrings 💡
🧪 Generate unit tests (beta)
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webhanspeter
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September 4, 2026 11:55
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September 4, 2026 11:56
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🟡 Changes recommended
One-shot iterables, lossy serialization, unchecked writes, and an order-dependent memory test introduce correctness and reliability risks.
Once you've addressed the issues Copilot identified, you can request another Copilot review.
Pull request overview
Introduces disk-backed row streaming to reduce memory usage during large exports.
Changes:
- Adds
RowStreambuffering and normalization. - Updates processors and CSV generation to consume iterable rows.
- Adds streaming, normalization, and memory tests.
File summaries
| File | Description |
|---|---|
src/Processor/RowStream.php |
Adds disk-backed row storage. |
src/Processor/ProcessorData.php |
Supports iterable row data. |
src/Processor/EloquentProcessor.php |
Streams processed rows. |
src/Generator/CsvDriver.php |
Writes rows without materializing them. |
tests/Feature/Processor/RowStreamTest.php |
Tests streaming behavior and memory. |
tests/Feature/Processor/ProcessorDataTest.php |
Tests iterable data access. |
tests/Feature/Generator/CsvDriverTest.php |
Tests streamed CSV output. |
phpstan-baseline.neon |
Removes an obsolete suppression. |
Review details
- Files reviewed: 8/8 changed files
- Comments generated: 5
- Review effort level: Balanced
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Actionable comments posted: 1
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Inline comments:
In `@src/Processor/RowStream.php`:
- Around line 71-76: Update push() in Processor\RowStream around the fwrite call
to capture its return value and fail when it returns false or fewer bytes than
the complete encoded JSON line length. Increment $this->count only after the
full line is successfully written, preserving accurate ProcessorData::getCount()
results.
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ℹ️ Review info
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📒 Files selected for processing (8)
phpstan-baseline.neonsrc/Generator/CsvDriver.phpsrc/Processor/EloquentProcessor.phpsrc/Processor/ProcessorData.phpsrc/Processor/RowStream.phptests/Feature/Generator/CsvDriverTest.phptests/Feature/Processor/ProcessorDataTest.phptests/Feature/Processor/RowStreamTest.php
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webhanspeter
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Sep 4, 2026
b = sys.argv[1]
old = "Subclasses that only pass the result into `new ProcessorData(...)` need no change; `ProcessorData` now accepts any iterable of rows."
new = "Subclasses that only pass the result into `new ProcessorData(...)` need no change; `ProcessorData` accepts either an array of rows or a `RowStream`. A one-shot iterable is deliberately not accepted, since the first reader would exhaust it."
b = b.replace(old, new) if old in b else b + "\n\n(Note: `ProcessorData` accepts an array or a `RowStream`, not an arbitrary iterable.)"
old2 = "Rows now go into a `RowStream` the moment they are built. It is a buffer that lives in memory up to 8 MB and spills to a temp file beyond that, and it tracks the fixed and optional column names as rows arrive."
new2 = "Rows now go into a `RowStream` the moment they are built. It is a length-framed buffer that lives in memory up to 8 MB and spills to a temp file beyond that, stores every value as the string the file will contain, and tracks the fixed and optional column names as rows arrive."
b = b.replace(old2, new2) if old2 in b else b
print(b, end='')
PY
gh pr edit 118 --repo worksome/data-export --body-file /tmp/pr118_body.md >/dev/null && rm -f /tmp/pr118_body.md && echo "PR body updated" && cd /Users/hanspeter/.claude/projects/-Users-hanspeter-Documents-Claude-Projects-MSP-functionality-in-Worksome-codebase/memory && python3 - <<'PY'
import io
p = 'project_jira_17824_csvdriver.md'
s = io.open(p, encoding='utf-8').read().rstrip('\n') + """
**Review round on #118 (2026-09-04):** 5 Copilot + 1 CodeRabbit comments; all six were valid, including one I had doubted (v3.0.0 `writeCsv()` DID guard `is_resource($stream)` - diff before pushing back). Result: `ProcessorData` narrowed to `array|RowStream` (one-shot iterables exhausted by `getColumns()`); spool changed from JSON lines to **length-framed `serialize()` with values cast to string at push** (JSON mangled `Stringable` and threw on invalid UTF-8); `fwrite` checked and count incremented only after a full write; read side verifies frame length; `memory_reset_peak_usage()` before the memory-bound baseline.
"""
io.open(p, 'w', encoding='utf-8').write(s + '\n')
print('memory updated')
PY
fix: JIRA-17851 harden the export row buffer after review
ProcessorData now takes an array or a RowStream rather than any iterable.
A one-shot iterable would be exhausted by the column lookup before the
rows were read, and nothing passes one anyway.
The buffer stores each value as the string the file will contain and uses
a length-framed serialize() spool rather than JSON lines. JSON turned a
Stringable into an array and refused bytes that are not valid UTF-8; both
now round-trip exactly, and a value that cannot become a string fails at
once with a clear message. Writes are checked against the frame length
and the row count only moves after a complete write, and reads verify
each frame so a truncated buffer fails loudly rather than yielding a
partial row.
The CSV writer checks the stream is a resource again before doing any
work, which the streaming rewrite had dropped. The memory test resets
the process peak before its baseline so the bound measures only itself.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
ProcessorData now takes an array or a RowStream rather than any iterable. A one-shot iterable would be exhausted by the column lookup before the rows were read, and nothing passes one anyway. The buffer stores each value as the string the file will contain and uses a length-framed serialize() spool rather than JSON lines. JSON turned a Stringable into an array and refused bytes that are not valid UTF-8; both now round-trip exactly, and a value that cannot become a string fails at once with a clear message. Writes are checked against the frame length and the row count only moves after a complete write, and reads verify each frame so a truncated buffer fails loudly rather than yielding a partial row. The CSV writer checks the stream is a resource again before doing any work, which the streaming rewrite had dropped. The memory test resets the process peak before its baseline so the bound measures only itself. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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🟡 Changes recommended
Late fixed columns can change legacy CSV header ordering despite the compatibility claim.
Once you've addressed the issues Copilot identified, you can request another Copilot review.
Review details
- Files reviewed: 8/8 changed files
- Comments generated: 1
- Review effort level: Balanced
owenvoke
reviewed
Sep 4, 2026
Second review round on the row stream. The header put every fixed column before the optional ones. The old normalisation appended the optional keys to every row and the writer took the header as the union of row keys in first-seen order, so a fixed column that first appeared in a later row used to come after the optional columns. The stream now remembers how many fixed columns the first row had and reproduces that order, with a test for the case. ProcessorData::getData() is removed on the maintainer's request. It was the one way left to pull a whole export back into memory, the package tests were its only callers, and this is a major release. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
owenvoke
approved these changes
Sep 4, 2026
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Summary
EloquentProcessor::filterQuery()built every row of an export into one array, andnormalizeOptionalItems()then made a second full pass over it to fill in the optional columns. So memory grew with the size of the export. Streaming the generator (v3.0.0) made the file writer flat, but the processor still held the whole export, and exports around 100k rows were exhausting a 2 GB process limit.Rows now go into a
RowStreamthe moment they are built. It is a length-framed buffer that lives in memory up to 8 MB and spills to a temp file beyond that, stores every value as the string the file will contain, and tracks the fixed and optional column names as rows arrive. Reading it back fills each row out to the final column list. The CSV writer consumes rows one at a time and takes the header from the stream's column list, so nothing ever holds the whole export.Why the buffer, and not a plain generator
An optional column only exists once some row has a value for it, so the header cannot be written until every row has been built. A plain generator would need a second pass over the database. Spilling the built rows to disk keeps a single database pass and flat memory.
Behaviour is unchanged
The normalisation rules move into
RowStreamunchanged, and each is now covered by a test:Verified in a consuming application on a realistic export with custom optional columns, values containing commas and quotes, and several parent records: header identical to v3.0.0, and 0 field differences across every column that is not an auto-increment id or a generated name. A three-chunk export that previously grew by 2-4 MB per chunk now stays flat between chunks.
Measured
RowStreamTest: 50,000 rows of ~1 KB each - which would be ~50 MB held in memory - grow the process by under 24 MB, and the bound does not move with the row count.Breaking changes
Needs a major release.
filterQuery()returns aRowStreamrather than an array. Subclasses that only pass the result intonew ProcessorData(...)need no change;ProcessorDataaccepts either an array of rows or aRowStream. A one-shot iterable is deliberately not accepted, since the first reader would exhaust it.ProcessorDatagainsrows(),getColumns()andgetCount(), and losesgetData(). It was the one way to pull a whole export back into memory, which is what this change removes;iterator_to_array($processorData->rows(), false)gives the same array where a test needs one.getAllOptionalKeys()andnormalizeOptionalItems()are removed fromEloquentProcessor.RowStreamis re-iterable andCountable, so anything that counted or looped the old array keeps working.Test plan
RowStreamtests: header order (including a column that first appears in a later row), precedence, padding, re-iteration, empty, byte-exact values, stringification, refusing a non-stringable value, and the 50k-row memory bound.ProcessorDatacovered for both aRowStreamand a plain array.CsvDriverwrites aRowStreamwith the header from its columns.rows()and are green with the same expected arrays.🤖 Generated with Claude Code
Summary by CodeRabbit
New Features
Bug Fixes
Tests