We cannot distinguish between legitimate ghosts and mis-threaded
messages before commit
83425ef12e4b65cdcecd11ddcb38175d4a91d5a0
("searchidx: deal with empty In-Reply-To and References headers")
so we must rebuild the index in parallel to fix it.
# 10 - optimize doc for NNTP overviews
# 11 - merge threads when vivifying ghosts
# 12 - change YYYYMMDD value column to numeric
- SCHEMA_VERSION => 12,
+ # 13 - fix threading for empty References/In-Reply-To
+ # (commit 83425ef12e4b65cdcecd11ddcb38175d4a91d5a0)
+ SCHEMA_VERSION => 13,
# n.b. FLAG_PURE_NOT is expensive not suitable for a public website
# as it could become a denial-of-service vector