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GM_Match Table

The GM_Match table holds one summary row per DNA match in GEDmatch — the kit-to-kit relationship between your kit and another kit, with the shared and largest centimorgan totals and an estimated number of generations. The per-chromosome detail behind these totals lives in GM_Segment.

GEDmatch gathering is currently unavailable in the Client and is expected to return in a future update. This page documents the schema and the behavior of the existing gather code as written.

kita and kitb

In this table kita is your (primary) kit — the base kit being gathered — and kitb is the match kit. A match row is written once per kita/kitb pair. Inserts are de-duplicated on that pair, so an existing row is not overwritten on a re-gather.

How It Is Populated

  • Match list — the primary source. Populates shared, largest, x_largest, x_shared, and gen, and sets matchdate to the time of the gather. Matches outside the configured minimum/maximum cM range are skipped.
  • AutoSegment / cluster nodes — populates only shared, largest, and matchdate.
  • ICW gather — when in-common-with data is gathered for a pair, icwdate is set on the matching GM_Match row.

Column Reference

ColumnTypeDescription
Idint (PK)Auto-incrementing primary key
kitastringYour (primary) kit number — the base kit being gathered. References GM_Kit.kit_num.
kitbstringThe match kit number. References GM_Kit.kit_num.
largestdecimalLargest shared autosomal segment, in cM.
x_largestdecimalLargest shared X-chromosome segment, in cM.
x_shareddecimalTotal shared X-chromosome DNA, in cM.
shareddecimalTotal shared autosomal DNA, in cM.
gendecimalGEDmatch’s estimated number of generations to a common ancestor.
matchdateDateTimeWhen the match summary was gathered.
icwdateDateTimeWhen in-common-with data was last gathered for this pair. Set during the ICW stage.
segdateDateTimeIntended to record when segment data was last gathered for this pair. Not assigned by the current gather code.
segdate exists in the schema but is not written by the current GEDmatch gather code, so it remains at its default value.

Related Tables

  • GM_Kit — kit registry; resolves kita / kitb to names, emails, and haplogroups.
  • GM_Segment — the per-chromosome segments that make up the shared totals on this row.
  • GM_ICW — the shared (in-common-with) matches behind icwdate.