Recommend synthetic _source before disabling _source entirely - #7699
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ash9146 wants to merge 5 commits into
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Recommend synthetic _source before disabling _source entirely#7699ash9146 wants to merge 5 commits into
ash9146 wants to merge 5 commits into
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The mapping-source-field.md reference page lists synthetic _source as the first option to consider for reducing _source disk usage, before disabling _source completely - but this production-guidance page only covered the latter, more disruptive option (reindex/update stop working). Synthetic _source avoids that tradeoff for most common field types by reconstructing _source at retrieval time from doc_values instead of storing it. Notes the Enterprise subscription requirement (per elastic.co/subscriptions, synthetic _source has been an Enterprise feature since 8.17) and the minor document-shape differences synthetic _source can introduce, so this isn't presented as a free lunch.
shainaraskas
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…age.md Co-authored-by: shainaraskas <58563081+shainaraskas@users.noreply.github.com>
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thanks for your contribution, @ash9146 - hope you don't mind me merging these :) |
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Thank you so much for the thorough reviews and support! Happy to contribute! 😊 |
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Summary
The
mapping-source-field.mdreference page lists synthetic_sourceas the first option to consider for reducing
_sourcedisk usage,before disabling
_sourcecompletely:This production-guidance page (
disk-usage.md) only covered the second,more disruptive option under "Disable
_source" - reindex, update, andhighlighting stop working once
_sourceis disabled. Synthetic_sourceavoids that tradeoff for most common field types byreconstructing
_sourceat retrieval time fromdoc_valuesinstead ofstoring it, so reindex and update continue to work normally.
What's added
A new "Reduce
_sourcestorage overhead" section, placed right beforethe existing "Disable
_source" section, that:_sourceas the option to consider first(per elastic.co/subscriptions, synthetic
_sourcehas been anEnterprise feature since 8.17)
_sourcecan differ slightly from theoriginal document (field order, array handling), linking to the
relevant reference section for details
This isn't presented as a strictly better replacement for the existing
"Disable
_source" section - both stay, since synthetic_sourcerequires a subscription and has its own caveats, so fully disabling
_sourceremains a valid option for some readers.Testing
"Disable
_source"