(JP) 全件scanの多重実行を複数回行うと、Assertion Failedとなることがある。

[taiki-k]

#15 と似た試験になりますが、pgbenchによる多重実行をシェルスクリプトでループさせて走らせていたところ、発生しました。

pgbenchで、2多重での実行で、高確率で発生します。(まれに、発生しないこともあります)

• バックトレース

#0  0x0000003cdbc32925 in raise () from /lib64/libc.so.6
#1  0x0000003cdbc34105 in abort () from /lib64/libc.so.6
#2  0x0000000000949085 in ExceptionalCondition (conditionName=0x7f34909a754e "!(nremain > 0 && nmoved > 0)",
    errorType=0x7f34909a6f44 "FailedAssertion", fileName=0x7f34909a6fa9 "tcache.c", lineNumber=1579) at assert.c:54
#3  0x00007f349098afbd in tcache_split_tcnode (tc_head=0x7f3488702018, tc_node_old=0x7f3488702200) at tcache.c:1579
#4  0x00007f349098d96d in tcache_insert_tuple (tc_head=0x7f3488702018, tc_node=0x7f3488702200, tuple=0x16c1e08) at tcache.c:2118
#5  0x00007f349098d7f5 in tcache_insert_tuple (tc_head=0x7f3488702018, tc_node=0x7f34887065c8, tuple=0x16c1e08) at tcache.c:2086
#6  0x00007f349098d7f5 in tcache_insert_tuple (tc_head=0x7f3488702018, tc_node=0x7f3488706528, tuple=0x16c1e08) at tcache.c:2086
#7  0x00007f349098d7f5 in tcache_insert_tuple (tc_head=0x7f3488702018, tc_node=0x7f34887062a8, tuple=0x16c1e08) at tcache.c:2086
#8  0x00007f349098d7f5 in tcache_insert_tuple (tc_head=0x7f3488702018, tc_node=0x7f3488706028, tuple=0x16c1e08) at tcache.c:2086
#9  0x00007f349098d7f5 in tcache_insert_tuple (tc_head=0x7f3488702018, tc_node=0x7f34887035b0, tuple=0x16c1e08) at tcache.c:2086
#10 0x00007f349098da77 in tcache_build_main (tc_scan=0x16bf870) at tcache.c:2149
#11 0x00007f349098df41 in tcache_scan_next (tc_scan=0x16bf870) at tcache.c:2281
#12 0x00007f3490995bd0 in pgstrom_load_gpuscan (gss=0x16be658) at gpuscan.c:953
#13 0x00007f3490996ce4 in gpuscan_fetch_tuple (node=0x16be658) at gpuscan.c:1278
#14 0x00007f3490997163 in gpuscan_exec (node=0x16be658) at gpuscan.c:1373
#15 0x00000000006807e7 in ExecCustomPlan (cpstate=0x16be658) at nodeCustom.c:37
#16 0x00000000006684b5 in ExecProcNode (node=0x16be658) at execProcnode.c:453
#17 0x000000000067dab4 in agg_retrieve_direct (aggstate=0x16bdec0) at nodeAgg.c:1164
#18 0x000000000067d9cb in ExecAgg (node=0x16bdec0) at nodeAgg.c:1117
#19 0x0000000000668548 in ExecProcNode (node=0x16bdec0) at execProcnode.c:487
#20 0x0000000000665efe in ExecutePlan (estate=0x16bdda8, planstate=0x16bdec0, operation=CMD_SELECT, sendTuples=1 '\001',
    numberTuples=0, direction=ForwardScanDirection, dest=0x16b5448) at execMain.c:1475
#21 0x0000000000663da8 in standard_ExecutorRun (queryDesc=0x16a47f8, direction=ForwardScanDirection, count=0) at execMain.c:308
#22 0x0000000000663beb in ExecutorRun (queryDesc=0x16a47f8, direction=ForwardScanDirection, count=0) at execMain.c:256
#23 0x00000000007f964e in PortalRunSelect (portal=0x16bbd98, forward=1 '\001', count=0, dest=0x16b5448) at pquery.c:946
#24 0x00000000007f9275 in PortalRun (portal=0x16bbd98, count=9223372036854775807, isTopLevel=1 '\001', dest=0x16b5448,
    altdest=0x16b5448, completionTag=0x7fff14bd5a40 "") at pquery.c:790
#25 0x00000000007f29e2 in exec_simple_query (query_string=0x166d568 "SELECT count(*) FROM million_table_i8f8 WHERE data < 0.01;")
    at postgres.c:1045
#26 0x00000000007f7162 in PostgresMain (argc=1, argv=0x15ff520, dbname=0x15ff418 "pgstrom_test", username=0x15ff3f8 "tkondo")
    at postgres.c:4004
#27 0x000000000076e18a in BackendRun (port=0x1627230) at postmaster.c:4104
#28 0x000000000076d840 in BackendStartup (port=0x1627230) at postmaster.c:3778
#29 0x0000000000769bfe in ServerLoop () at postmaster.c:1569
#30 0x0000000000769251 in PostmasterMain (argc=1, argv=0x15fe3b0) at postmaster.c:1222
#31 0x00000000006b8aee in main (argc=1, argv=0x15fe3b0) at main.c:223

• 実行したクエリー

SELECT count(*) FROM million_table_i8f8 WHERE data < 0.01;

• 対象のテーブル

   Table "public.million_table_i8f8"
 Column |       Type       | Modifiers
--------+------------------+-----------
 id     | bigint           |
 data   | double precision |

※ million_table ( #10 で使用したもの)をCOPYでファイルに出力し、million_table_i8f8に入力したものです。

• 使用したシェルスクリプト

#!/bin/bash

RES=0;
COUNT=1;

while [ $RES -eq 0 ];
do
        echo -n Try count $COUNT Start at ;
        date;
        pgbench $@;
        RES=$?;
        COUNT=`expr $COUNT + 1`;
done;

この時のCoreは、以下にbzip2圧縮して置いてありますので、解析にご利用ください。

/home/tkondo/coding/postgres/pg_strom_test/core/core.502.2014-05-15_18-12.bz2

[kaigai]

tcache_headを登録するハッシュ表のロックに関連する問題を修正後、再現しないので、
一旦クローズとする。