[YSQL] Occasional SIGSEGV in yb_cost_index

[gauravk-in]

Jira Link: DB-7600

Description

Following query with more than one inequality filter on more than one index keys can lead to a very occasional SIGSEGV.

This only occurs when the new base scans cost model is enabled.

SET yb_enable_base_scans_cost_model = ON;
SET yb_enable_optimizer_statistics = ON;
create table test (k1 int, k2 int, k3 int, PRIMARY KEY (k1 ASC, k2 ASC, k3 ASC));
ANALYZE test;
/*+ IndexScan(test) */ explain select * from test where k1 > 10 and k1 < 20 and k2 > 10 and k2 < 30;

Here is the backtrace from the coredump.

* thread #1, name = 'postgres', stop reason = signal SIGSEGV
  * frame #0: 0x000055b42e04cdb4 postgres`list_nth_cell(list=0x0000000000000000, n=-2) at list.c:396:17
    frame #1: 0x000055b42e08e945 postgres`yb_cost_index(path=0x0000258abf17f570, root=0x0000258abf9c04b0, loop_count=1, partial_path=<unavailable>) at costsize.c:6337:14
    frame #2: 0x000055b42e0c8d34 postgres`create_index_path(root=0x0000258abf9c04b0, index=0x0000258abf9c1e58, indexclauses=0x0000258abf17f3e8, indexclausecols=0x0000258abf17f438, indexorderbys=0x0000000000000000, indexorderbycols=0x0000000000000000, pathkeys=0x0000000000000000, indexscandir=ForwardScanDirection, indexonly=<unavailable>, required_outer=0x0000000000000000, loop_count=0, partial_path=<unavailable>) at pathnode.c:1312:3
    frame #3: 0x000055b42e096375 postgres`build_index_paths(root=0x0000258abf9c04b0, rel=0x0000258abf9c1ab0, index=0x0000258abf9c1e58, clauses=0x00007ffe444453e8, useful_predicate=<unavailable>, scantype=ST_ANYSCAN, skip_nonnative_saop=0x00007ffe444453a7, skip_lower_saop=0x00007ffe444453a6) at indxpath.c:1332:11
    frame #4: 0x000055b42e093107 postgres`get_index_paths(root=<unavailable>, rel=<unavailable>, index=<unavailable>, clauses=<unavailable>, bitindexpaths=0x00007ffe44445728) at indxpath.c:959:15
    frame #5: 0x000055b42e092900 postgres`create_index_paths(root=0x0000258abf9c04b0, rel=0x0000258abf9c1ab0) at indxpath.c:281:3
    frame #6: 0x000055b42e022b3b postgres`ybcGetForeignPaths(root=0x0000258abf9c04b0, baserel=0x0000258abf9c1ab0, foreigntableid=<unavailable>) at ybc_fdw.c:177:2
    frame #7: 0x000055b42e086214 postgres`set_rel_pathlist(root=0x0000258abf9c04b0, rel=0x0000258abf9c1ab0, rti=1, rte=0x0000258abeb8db00) at allpaths.c:0
    frame #8: 0x000055b42e08305f postgres`make_one_rel at allpaths.c:360:3
    frame #9: 0x000055b42e083015 postgres`make_one_rel(root=0x0000258abf9c04b0, joinlist=0x0000258abf9c1e28) at allpaths.c:230:2
    frame #10: 0x000055b42e0ab905 postgres`query_planner(root=0x0000258abf9c04b0, tlist=0x0000258abf9c0f50, qp_callback=<unavailable>, qp_extra=0x00007ffe444459a8) at planmain.c:265:14
    frame #11: 0x000055b42e0ae923 postgres`grouping_planner(root=0x0000258abf9c04b0, inheritance_update=<unavailable>, tuple_fraction=<unavailable>) at planner.c:1928:17
    frame #12: 0x000055b42e0ace34 postgres`subquery_planner(glob=0x0000258abf9c0e00, parse=0x0000258abeb8d9f0, parent_root=0x0000000000000000, hasRecursion=false, tuple_fraction=0) at planner.c:976:3
    frame #13: 0x000055b42e0abc10 postgres`standard_planner(parse=0x0000258abeb8d9f0, cursorOptions=256, boundParams=<unavailable>) at planner.c:405:9
    frame #14: 0x00007ffab49cb053
    frame #15: 0x000055b42e1883f0 postgres`pg_plan_queries [inlined] pg_plan_query(querytree=<unavailable>, cursorOptions=<unavailable>, boundParams=0x0000000000000000) at postgres.c:893:9
    frame #16: 0x000055b42e1883b9 postgres`pg_plan_queries(querytrees=<unavailable>, cursorOptions=<unavailable>, boundParams=0x0000000000000000) at postgres.c:959:11
    frame #17: 0x000055b42e18f077 postgres`yb_exec_simple_query_impl at postgres.c:1136:19
    frame #18: 0x000055b42e18eb44 postgres`yb_exec_simple_query_impl(query_string=0x0000258abfd06118) at postgres.c:4748:2
    frame #19: 0x000055b42e18f7b9 postgres`yb_exec_query_wrapper_one_attempt(exec_context=0x0000258abfd06000, restart_data=0x00007ffe444461a0, functor=(postgres`yb_exec_simple_query_impl at postgres.c:4747), functor_context=0x0000258abfd06118, attempt=0, retry=0x00007ffe444463c8) at postgres.c:4716:3
    frame #20: 0x000055b42e18bb88 postgres`PostgresMain at postgres.c:4740:3
    frame #21: 0x000055b42e18bb54 postgres`PostgresMain [inlined] yb_exec_simple_query(query_string="/*+  SeqScan(t_range_1m_4keys) */ select * from t_range_1m_4keys where k1 > 2 and k1 < 8 and k2 > 5 and k2 < 10", exec_context=0x0000258abfd06000) at postgres.c:4763:2
    frame #22: 0x000055b42e18bb4d postgres`PostgresMain(argc=<unavailable>, argv=0x0000258abfcd13c8, dbname=<unavailable>, username=<unavailable>) at postgres.c:5388:23
    frame #23: 0x000055b42e0f6b31 postgres`BackendRun(port=0x0000258abfc081e0) at postmaster.c:4658:2
    frame #24: 0x000055b42e0f5f0d postgres`ServerLoop [inlined] BackendStartup(port=0x0000258abfc081e0) at postmaster.c:4296:3
    frame #25: 0x000055b42e0f5ecc postgres`ServerLoop at postmaster.c:1775:7
    frame #26: 0x000055b42e0f216b postgres`PostmasterMain(argc=25, argv=0x0000258abfd00000) at postmaster.c:1431:11
    frame #27: 0x000055b42e048f06 postgres`PostgresServerProcessMain(argc=25, argv=0x0000258abfd00000) at main.c:234:3
    frame #28: 0x000055b42e049502 postgres`main + 34

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