Prevent out of memory errors by reducing work_mem?

Hi,

I´m getting an out of memory error running the following query over 6
tables (the *BASE* tables have over 1 million rows each) on Postgresql
9.1. The machine has 4GB RAM:

SELECT *
FROM dtng."Z_BASE" zb
LEFT JOIN dtng."Z_BASE_COUNTRY" zbc ON zb."ISIN" = zbc."ISIN"
LEFT JOIN dtng."PRODUCT_TYPES" pt ON zb."ID_PRODUCT_TYPE" =
pt."ID_PRODUCT_TYPE"
JOIN voola.export_product_groups epg ON pt."ID_PRODUCT_GROUP" =
epg.id_product_group
FULL OUTER JOIN warrants."W_BASE" wb ON zb."ISIN" = wb."ISIN"
LEFT JOIN warrants."W_BASE_COUNTRY" wbc ON wb."ISIN" = wbc."ISIN"
WHERE coalesce(zbc."ID_COUNTRY", wbc."ID_COUNTRY") = 'DE'

This is the query plan:

Hash Right Join (cost=1498106.22..2102918.77 rows=7487 width=2708)
Hash Cond: ((wbc."ISIN")::bpchar = (wb."ISIN")::bpchar)
Filter: ((COALESCE(zbc."ID_COUNTRY", wbc."ID_COUNTRY"))::bpchar =
'DE'::bpchar)
-> Seq Scan on "W_BASE_COUNTRY" wbc (cost=0.00..45668.41 rows=1497341
width=160)
-> Hash (cost=1015864.28..1015864.28 rows=1474955 width=2548)
-> Hash Full Join (cost=420009.31..1015864.28 rows=1474955 width=2548)
Hash Cond: ((zb."ISIN")::bpchar = (wb."ISIN")::bpchar)
-> Hash Right Join (cost=266400.82..518612.27 rows=505517 width=2341)
Hash Cond: ((zbc."ISIN")::bpchar = (zb."ISIN")::bpchar)
-> Seq Scan on "Z_BASE_COUNTRY" zbc (cost=0.00..47831.60 rows=1614860
width=106)
-> Hash (cost=120372.86..120372.86 rows=505517 width=2235)
-> Hash Join (cost=662.44..120372.86 rows=505517 width=2235)
Hash Cond: (zb."ID_PRODUCT_TYPE" = pt."ID_PRODUCT_TYPE")
-> Seq Scan on "Z_BASE" zb (cost=0.00..106484.75 rows=1634275 width=1377)
-> Hash (cost=631.12..631.12 rows=2506 width=858)
-> Hash Join (cost=2.64..631.12 rows=2506 width=858)
Hash Cond: (pt."ID_PRODUCT_GROUP" = (epg.id_product_group)::bpchar)
-> Seq Scan on "PRODUCT_TYPES" pt (cost=0.00..573.03 rows=8103 width=853)
-> Hash (cost=1.73..1.73 rows=73 width=5)
-> Seq Scan on export_product_groups epg (cost=0.00..1.73 rows=73 width=5)
-> Hash (cost=93399.55..93399.55 rows=1474955 width=207)
-> Seq Scan on "W_BASE" wb (cost=0.00..93399.55 rows=1474955 width=207)

I tried reducing work_mem from 8MB to 64kB to force usage of temporary
files for the hash joins instead of working memory, as written in
chapter 18.4.1 of the documentation. But that didn´t help.

I know that the query is poorly written and already rewrote it to use
less memory. My question is if/how it is possible to prevent the out of
memory error at the price of speed (disk usage).I already searched the
internet for an answer but without luck...

Thanks a lot,
Jan

P.S.: Here is the Postgres log:

TopMemoryContext: 2181968 total in 13 blocks; 9888 free (12 chunks);
2172080 used
TopTransactionContext: 8192 total in 1 blocks; 7112 free (0 chunks);
1080 used
Type information cache: 24576 total in 2 blocks; 11888 free (5 chunks);
12688 used
Record information cache: 24576 total in 2 blocks; 15984 free (5
chunks); 8592 used
TableSpace cache: 8192 total in 1 blocks; 3216 free (0 chunks); 4976 used
Operator lookup cache: 24576 total in 2 blocks; 11888 free (5 chunks);
12688 used
Prepared Queries: 24576 total in 2 blocks; 15984 free (5 chunks); 8592 used
MessageContext: 8192 total in 1 blocks; 6976 free (0 chunks); 1216 used
Operator class cache: 8192 total in 1 blocks; 1680 free (0 chunks); 6512
used
smgr relation table: 24576 total in 2 blocks; 5696 free (4 chunks);
18880 used
TransactionAbortContext: 32768 total in 1 blocks; 32736 free (0 chunks);
32 used
Portal hash: 8192 total in 1 blocks; 1680 free (0 chunks); 6512 used
PortalMemory: 8192 total in 1 blocks; 7888 free (0 chunks); 304 used
PortalHoldContext: 24576 total in 2 blocks; 15888 free (4 chunks); 8688 used
PortalHeapMemory: 534144 total in 68 blocks; 6656 free (14 chunks);
527488 used
ExecutorState: 3442985408 total in 412394 blocks; 5173848 free (16
chunks); 3437811560 used
HashTableContext: 0 total in 0 blocks; 0 free (0 chunks); 0 used
HashBatchContext: 16384 total in 1 blocks; 2304 free (0 chunks); 14080 used
HashTableContext: 0 total in 0 blocks; 0 free (0 chunks); 0 used
HashBatchContext: 262144 total in 5 blocks; 74976 free (3 chunks);
187168 used
HashTableContext: 8192 total in 1 blocks; 6080 free (0 chunks); 2112 used
HashBatchContext: 4194304 total in 9 blocks; 79984 free (11 chunks);
4114320 used
HashTableContext: 8192 total in 1 blocks; 7104 free (0 chunks); 1088 used
HashBatchContext: 8421424 total in 12 blocks; 2017200 free (13 chunks);
6404224 used
HashTableContext: 67166304 total in 5 blocks; 57248 free (15 chunks);
67109056 used
HashBatchContext: 234881024 total in 37 blocks; 259488 free (62 chunks);
234621536 used
ExprContext: 0 total in 0 blocks; 0 free (0 chunks); 0 used
ExprContext: 0 total in 0 blocks; 0 free (0 chunks); 0 used
ExprContext: 0 total in 0 blocks; 0 free (0 chunks); 0 used
ExprContext: 0 total in 0 blocks; 0 free (0 chunks); 0 used
ExprContext: 0 total in 0 blocks; 0 free (0 chunks); 0 used
ExprContext: 8192 total in 1 blocks; 8160 free (0 chunks); 32 used
ExprContext: 0 total in 0 blocks; 0 free (0 chunks); 0 used
ExprContext: 0 total in 0 blocks; 0 free (0 chunks); 0 used
ExprContext: 8192 total in 1 blocks; 8160 free (0 chunks); 32 used
ExprContext: 0 total in 0 blocks; 0 free (0 chunks); 0 used
ExprContext: 0 total in 0 blocks; 0 free (0 chunks); 0 used
ExprContext: 8192 total in 1 blocks; 8160 free (0 chunks); 32 used
ExprContext: 8192 total in 1 blocks; 8160 free (0 chunks); 32 used
ExprContext: 0 total in 0 blocks; 0 free (0 chunks); 0 used
ExprContext: 0 total in 0 blocks; 0 free (0 chunks); 0 used
ExprContext: 0 total in 0 blocks; 0 free (0 chunks); 0 used
Relcache by OID: 24576 total in 2 blocks; 12832 free (3 chunks); 11744 used
CacheMemoryContext: 1390112 total in 23 blocks; 70696 free (1 chunks);
1319416 used
unnamed prepared statement: 516096 total in 6 blocks; 192440 free (4
chunks); 323656 used
tmp_idx: 2048 total in 1 blocks; 72 free (0 chunks); 1976 used
PRODUCT_TYPES_pkey: 2048 total in 1 blocks; 728 free (0 chunks); 1320 used
PRODUCT_TYPES_ID_PRODUCT_TYPE_key: 2048 total in 1 blocks; 712 free (0
chunks); 1336 used
W_BASE_COUNTRY_NSIN: 2048 total in 1 blocks; 776 free (0 chunks); 1272 used
W_BASE_COUNTRY_ISIN: 2048 total in 1 blocks; 728 free (0 chunks); 1320 used
W_BASE_COUNTRY_pkey: 2048 total in 1 blocks; 712 free (0 chunks); 1336 used
W_BASE_pkey: 2048 total in 1 blocks; 728 free (0 chunks); 1320 used
Z_BASE_COUNTRY_STATUS: 2048 total in 1 blocks; 776 free (0 chunks); 1272
used
Z_BASE_COUNTRY_NSIN_ID_COUNTRY: 2048 total in 1 blocks; 176 free (0
chunks); 1872 used
Z_BASE_COUNTRY_NSIN: 2048 total in 1 blocks; 776 free (0 chunks); 1272 used
Z_BASE_COUNTRY_ISIN: 2048 total in 1 blocks; 728 free (0 chunks); 1320 used
Z_BASE_COUNTRY_ID_COUNTRY: 2048 total in 1 blocks; 776 free (0 chunks);
1272 used
Z_BASE_COUNTRY_pkey: 2048 total in 1 blocks; 712 free (0 chunks); 1336 used
Z_BASE_IS_INDICATIVE: 2048 total in 1 blocks; 776 free (0 chunks); 1272 used
Z_BASE_ID_PRODUCT_TYPE_index: 2048 total in 1 blocks; 728 free (0
chunks); 1320 used
Z_BASE_ID_ISSUER_GROUP_index: 2048 total in 1 blocks; 776 free (0
chunks); 1272 used
Z_BASE_ID_ISSUER_GROUP_ID_PRODUCT_TYPE_index: 2048 total in 1 blocks;
712 free (0 chunks); 1336 used
Z_BASE_pkey: 2048 total in 1 blocks; 728 free (0 chunks); 1320 used
pg_constraint_conrelid_index: 2048 total in 1 blocks; 728 free (0
chunks); 1320 used
CachedPlan: 1024 total in 1 blocks; 784 free (0 chunks); 240 used
CachedPlanSource: 1024 total in 1 blocks; 656 free (0 chunks); 368 used
pg_attrdef_oid_index: 2048 total in 1 blocks; 776 free (0 chunks); 1272 used
pg_attrdef_adrelid_adnum_index: 2048 total in 1 blocks; 664 free (0
chunks); 1384 used
pg_settings: 23552 total in 5 blocks; 3040 free (1 chunks); 20512 used
pg_toast_2619_index: 2048 total in 1 blocks; 664 free (0 chunks); 1384 used
pg_index_indrelid_index: 2048 total in 1 blocks; 728 free (0 chunks);
1320 used
CachedPlan: 1024 total in 1 blocks; 784 free (0 chunks); 240 used
CachedPlanSource: 1024 total in 1 blocks; 664 free (1 chunks); 360 used
pg_db_role_setting_databaseid_rol_index: 2048 total in 1 blocks; 664
free (0 chunks); 1384 used
pg_opclass_am_name_nsp_index: 3072 total in 2 blocks; 1496 free (2
chunks); 1576 used
pg_foreign_data_wrapper_name_index: 3072 total in 2 blocks; 1768 free (4
chunks); 1304 used
pg_enum_oid_index: 3072 total in 2 blocks; 1768 free (4 chunks); 1304 used
pg_class_relname_nsp_index: 3072 total in 2 blocks; 1656 free (3
chunks); 1416 used
pg_foreign_server_oid_index: 3072 total in 2 blocks; 1768 free (4
chunks); 1304 used
pg_statistic_relid_att_inh_index: 3072 total in 2 blocks; 1496 free (2
chunks); 1576 used
pg_cast_source_target_index: 3072 total in 2 blocks; 1656 free (3
chunks); 1416 used
pg_language_name_index: 3072 total in 2 blocks; 1768 free (4 chunks);
1304 used
pg_collation_oid_index: 3072 total in 2 blocks; 1768 free (4 chunks);
1304 used
pg_amop_fam_strat_index: 3072 total in 2 blocks; 1496 free (2 chunks);
1576 used
pg_index_indexrelid_index: 3072 total in 2 blocks; 1720 free (3 chunks);
1352 used
pg_ts_template_tmplname_index: 3072 total in 2 blocks; 1704 free (4
chunks); 1368 used
pg_ts_config_map_index: 3072 total in 2 blocks; 1544 free (2 chunks);
1528 used
pg_opclass_oid_index: 3072 total in 2 blocks; 1720 free (3 chunks); 1352
used
pg_foreign_data_wrapper_oid_index: 3072 total in 2 blocks; 1768 free (4
chunks); 1304 used
pg_ts_dict_oid_index: 3072 total in 2 blocks; 1768 free (4 chunks); 1304
used
pg_conversion_default_index: 3072 total in 2 blocks; 1544 free (2
chunks); 1528 used
pg_operator_oprname_l_r_n_index: 3072 total in 2 blocks; 1496 free (2
chunks); 1576 used
pg_trigger_tgrelid_tgname_index: 3072 total in 2 blocks; 1656 free (3
chunks); 1416 used
pg_enum_typid_label_index: 3072 total in 2 blocks; 1704 free (4 chunks);
1368 used
pg_ts_config_oid_index: 3072 total in 2 blocks; 1768 free (4 chunks);
1304 used
pg_user_mapping_oid_index: 3072 total in 2 blocks; 1768 free (4 chunks);
1304 used
pg_opfamily_am_name_nsp_index: 3072 total in 2 blocks; 1544 free (2
chunks); 1528 used
pg_foreign_table_relid_index: 3072 total in 2 blocks; 1768 free (4
chunks); 1304 used
pg_type_oid_index: 3072 total in 2 blocks; 1720 free (3 chunks); 1352 used
pg_aggregate_fnoid_index: 3072 total in 2 blocks; 1768 free (4 chunks);
1304 used
pg_constraint_oid_index: 3072 total in 2 blocks; 1768 free (4 chunks);
1304 used
pg_rewrite_rel_rulename_index: 3072 total in 2 blocks; 1656 free (3
chunks); 1416 used
pg_ts_parser_prsname_index: 3072 total in 2 blocks; 1704 free (4
chunks); 1368 used
pg_ts_config_cfgname_index: 3072 total in 2 blocks; 1704 free (4
chunks); 1368 used
pg_ts_parser_oid_index: 3072 total in 2 blocks; 1768 free (4 chunks);
1304 used
pg_operator_oid_index: 3072 total in 2 blocks; 1720 free (3 chunks);
1352 used
pg_namespace_nspname_index: 3072 total in 2 blocks; 1720 free (3
chunks); 1352 used
pg_ts_template_oid_index: 3072 total in 2 blocks; 1768 free (4 chunks);
1304 used
pg_amop_opr_fam_index: 3072 total in 2 blocks; 1496 free (2 chunks);
1576 used
pg_default_acl_role_nsp_obj_index: 3072 total in 2 blocks; 1544 free (2
chunks); 1528 used
pg_collation_name_enc_nsp_index: 3072 total in 2 blocks; 1544 free (2
chunks); 1528 used
pg_ts_dict_dictname_index: 3072 total in 2 blocks; 1704 free (4 chunks);
1368 used
pg_type_typname_nsp_index: 3072 total in 2 blocks; 1656 free (3 chunks);
1416 used
pg_opfamily_oid_index: 3072 total in 2 blocks; 1768 free (4 chunks);
1304 used
pg_class_oid_index: 3072 total in 2 blocks; 1720 free (3 chunks); 1352 used
pg_proc_proname_args_nsp_index: 3072 total in 2 blocks; 1496 free (2
chunks); 1576 used
pg_attribute_relid_attnum_index: 3072 total in 2 blocks; 1656 free (3
chunks); 1416 used
pg_proc_oid_index: 3072 total in 2 blocks; 1720 free (3 chunks); 1352 used
pg_language_oid_index: 3072 total in 2 blocks; 1768 free (4 chunks);
1304 used
pg_namespace_oid_index: 3072 total in 2 blocks; 1720 free (3 chunks);
1352 used
pg_amproc_fam_proc_index: 3072 total in 2 blocks; 1496 free (2 chunks);
1576 used
pg_foreign_server_name_index: 3072 total in 2 blocks; 1768 free (4
chunks); 1304 used
pg_attribute_relid_attnam_index: 3072 total in 2 blocks; 1704 free (4
chunks); 1368 used
pg_conversion_oid_index: 3072 total in 2 blocks; 1768 free (4 chunks);
1304 used
pg_user_mapping_user_server_index: 3072 total in 2 blocks; 1704 free (4
chunks); 1368 used
pg_conversion_name_nsp_index: 3072 total in 2 blocks; 1704 free (4
chunks); 1368 used
pg_authid_oid_index: 3072 total in 2 blocks; 1720 free (3 chunks); 1352 used
pg_auth_members_member_role_index: 3072 total in 2 blocks; 1656 free (3
chunks); 1416 used
pg_tablespace_oid_index: 3072 total in 2 blocks; 1720 free (3 chunks);
1352 used
pg_database_datname_index: 3072 total in 2 blocks; 1720 free (3 chunks);
1352 used
pg_auth_members_role_member_index: 3072 total in 2 blocks; 1704 free (4
chunks); 1368 used
pg_database_oid_index: 3072 total in 2 blocks; 1720 free (3 chunks);
1352 used
pg_authid_rolname_index: 3072 total in 2 blocks; 1720 free (3 chunks);
1352 used
MdSmgr: 8192 total in 1 blocks; 5024 free (0 chunks); 3168 used
LOCALLOCK hash: 24576 total in 2 blocks; 13920 free (4 chunks); 10656 used
Timezones: 83472 total in 2 blocks; 3744 free (0 chunks); 79728 used
ErrorContext: 8192 total in 1 blocks; 8160 free (0 chunks); 32 used
<2013-01-25 10:17:20 CET - strube> ERROR: out of memory
<2013-01-25 10:17:20 CET - strube> DETAIL: Failed on request of size 8240.