Peter, moving the conversation here from "pgsql: Improve nbtree skip scan primitive scan scheduling" thread on -committers. Attached is another regression test for your consideration, which gives rise to the following assertion:
TRAP: failed Assert("numSkipArrayKeys == 0"), File: "nbtpreprocesskeys.c", Line: 1859, PID: 7210 0 postgres 0x00000001032f30e0 ExceptionalCondition + 108 1 postgres 0x0000000102e83100 _bt_preprocess_keys + 6036 2 postgres 0x0000000102e87338 _bt_first + 168 3 postgres 0x0000000102e84680 btgettuple + 196 4 postgres 0x0000000102e75cdc index_getnext_tid + 68 5 postgres 0x00000001030017a0 IndexOnlyNext + 228 6 postgres 0x0000000102fe5b2c ExecScan + 228 7 postgres 0x0000000103011088 ExecSort + 536 8 postgres 0x0000000102fdbc68 standard_ExecutorRun + 312 9 postgres 0x00000001031bdfb8 PortalRunSelect + 236 10 postgres 0x00000001031bdbd4 PortalRun + 492 11 postgres 0x00000001031bcb18 exec_simple_query + 1292 12 postgres 0x00000001031b9d1c PostgresMain + 1388 13 postgres 0x00000001031b59a8 BackendInitialize + 0 14 postgres 0x000000010310edd8 postmaster_child_launch + 372 15 postgres 0x000000010311303c ServerLoop + 4948 16 postgres 0x0000000103111360 InitProcessGlobals + 0 17 postgres 0x0000000103030c00 help + 0 18 dyld 0x000000018eb17154 start + 2476 This looks sufficiently different from the assertion mentioned on the other thread to be worth posting here. — Mark Dilger EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
_skipscan2.sql
Description: application/sql