Re: Odd out of memory problem.

hello,

does the problem show up on 2% of all problems after 2 weeks or so?
we had a similar problem on UNIX as well. it even materialized on 100 identical boxes (on 2% of them). it pops up randomly and never stops …
i checked some code paths. some of those messages are direct output via stderr (not even elog).
unfortunately i did not manage to find a box where i could GDB to attack the problem .
it was 8.4.8 as well.

do you see a certain workload which would make the problem reproducable?

regards,

hans

On Mar 26, 2012, at 5:03 PM, Andrew Dunstan wrote:

>
> I'm not sure if this is a bug, but I have wrestling with this problem for a client.
>
> Platform is Windows Servers 2003 64 bit, PostgreSQL 8.4.8., 4Gb RAM, running on an Amazon VM.
>
> Shared buffers: 512Mb, work_mem: 25Mb. There are only a handful of connections to the database, and no other activity.
>
> We are seeing the error shown below. The table in question has two columns (Oid, int) and roughly 43m rows. The only other thing remarkable about the settings is that effective_cache_size is set to 5Gb, which is clearly too high, but surely that shouldn't cause a memory error.
>
> I'm really perplexed as to why this fairly simple query should cause an out of memory error:
>
> select loid, max(pageno) from ldata group by loid order by 2 desc
> limit 10;
>
> I can't see what I might be missing.
>
>
> cheers
>
> andrew
>
> TopMemoryContext: 49816 total in 6 blocks; 5384 free (7 chunks);
> 44432 used
> TopTransactionContext: 8192 total in 1 blocks; 7696 free (0
> chunks); 496 used
> Record information cache: 8192 total in 1 blocks; 1800 free (0
> chunks); 6392 used
> Type information cache: 8192 total in 1 blocks; 1800 free (0
> chunks); 6392 used
> Operator class cache: 8192 total in 1 blocks; 3848 free (0
> chunks); 4344 used
> Operator lookup cache: 24576 total in 2 blocks; 14072 free (6
> chunks); 10504 used
> MessageContext: 40960 total in 3 blocks; 29920 free (6 chunks);
> 11040 used
> smgr relation table: 8192 total in 1 blocks; 2816 free (0
> chunks); 5376 used
> TransactionAbortContext: 32768 total in 1 blocks; 32752 free (0
> chunks); 16 used
> Portal hash: 8192 total in 1 blocks; 3912 free (0 chunks); 4280 used
> PortalMemory: 8192 total in 1 blocks; 8040 free (0 chunks); 152 used
> PortalHeapMemory: 1024 total in 1 blocks; 920 free (0 chunks);
> 104 used
> ExecutorState: 8192 total in 1 blocks; 2144 free (1 chunks);
> 6048 used
> TupleSort: 40984 total in 3 blocks; 24208 free (10 chunks);
> 16776 used
> ExprContext: 0 total in 0 blocks; 0 free (0 chunks); 0 used
> AggContext: 864018432 total in 127 blocks; 3400 free (110
> chunks); 864015032 used
> TupleHashTable: 619175960 total in 95 blocks; 821528 free
> (331 chunks); 618354432 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: 8192 total in 1 blocks; 3376 free (0 chunks);
> 4816 used
> CacheMemoryContext: 667696 total in 20 blocks; 169960 free (2
> chunks); 497736 used
> pg_shdepend_reference_index: 1024 total in 1 blocks; 240 free
> (0 chunks); 784 used
> pg_depend_depender_index: 1024 total in 1 blocks; 152 free (0
> chunks); 872 used
> pg_depend_reference_index: 1024 total in 1 blocks; 152 free (0
> chunks); 872 used
> pg_largeobject_loid_pn_index: 1024 total in 1 blocks; 280 free
> (0 chunks); 744 used
> pg_database_datname_index: 1024 total in 1 blocks; 344 free (0
> chunks); 680 used
> pg_index_indrelid_index: 1024 total in 1 blocks; 304 free (0
> chunks); 720 used
> pg_opclass_am_name_nsp_index: 1024 total in 1 blocks; 152 free
> (0 chunks); 872 used
> pg_foreign_data_wrapper_name_index: 1024 total in 1 blocks; 344
> free (0 chunks); 680 used
> pg_enum_oid_index: 1024 total in 1 blocks; 344 free (0 chunks);
> 680 used
> pg_class_relname_nsp_index: 1024 total in 1 blocks; 240 free (0
> chunks); 784 used
> pg_foreign_server_oid_index: 1024 total in 1 blocks; 344 free
> (0 chunks); 680 used
> pg_statistic_relid_att_index: 1024 total in 1 blocks; 240 free
> (0 chunks); 784 used
> pg_cast_source_target_index: 1024 total in 1 blocks; 240 free
> (0 chunks); 784 used
> pg_language_name_index: 1024 total in 1 blocks; 344 free (0
> chunks); 680 used
> pg_authid_oid_index: 1024 total in 1 blocks; 304 free (0
> chunks); 720 used
> pg_amop_fam_strat_index: 1024 total in 1 blocks; 88 free (0
> chunks); 936 used
> pg_index_indexrelid_index: 1024 total in 1 blocks; 304 free (0
> chunks); 720 used
> pg_ts_template_tmplname_index: 1024 total in 1 blocks; 280 free
> (0 chunks); 744 used
> pg_ts_config_map_index: 1024 total in 1 blocks; 192 free (0
> chunks); 832 used
> pg_opclass_oid_index: 1024 total in 1 blocks; 304 free (0
> chunks); 720 used
> pg_foreign_data_wrapper_oid_index: 1024 total in 1 blocks; 344
> free (0 chunks); 680 used
> pg_auth_members_member_role_index: 1024 total in 1 blocks; 280
> free (0 chunks); 744 used
> pg_ts_dict_oid_index: 1024 total in 1 blocks; 344 free (0
> chunks); 680 used
> pg_conversion_default_index: 1024 total in 1 blocks; 128 free
> (0 chunks); 896 used
> pg_operator_oprname_l_r_n_index: 1024 total in 1 blocks; 88
> free (0 chunks); 936 used
> pg_trigger_tgrelid_tgname_index: 1024 total in 1 blocks; 240
> free (0 chunks); 784 used
> pg_enum_typid_label_index: 1024 total in 1 blocks; 280 free (0
> chunks); 744 used
> pg_ts_config_oid_index: 1024 total in 1 blocks; 344 free (0
> chunks); 680 used
> pg_user_mapping_oid_index: 1024 total in 1 blocks; 344 free (0
> chunks); 680 used
> pg_opfamily_am_name_nsp_index: 1024 total in 1 blocks; 192 free
> (0 chunks); 832 used
> pg_type_oid_index: 1024 total in 1 blocks; 304 free (0 chunks);
> 720 used
> pg_aggregate_fnoid_index: 1024 total in 1 blocks; 304 free (0
> chunks); 720 used
> pg_constraint_oid_index: 1024 total in 1 blocks; 344 free (0
> chunks); 680 used
> pg_rewrite_rel_rulename_index: 1024 total in 1 blocks; 280 free
> (0 chunks); 744 used
> pg_ts_parser_prsname_index: 1024 total in 1 blocks; 280 free (0
> chunks); 744 used
> pg_ts_config_cfgname_index: 1024 total in 1 blocks; 280 free (0
> chunks); 744 used
> pg_ts_parser_oid_index: 1024 total in 1 blocks; 344 free (0
> chunks); 680 used
> pg_operator_oid_index: 1024 total in 1 blocks; 304 free (0
> chunks); 720 used
> pg_namespace_nspname_index: 1024 total in 1 blocks; 304 free (0
> chunks); 720 used
> pg_ts_template_oid_index: 1024 total in 1 blocks; 344 free (0
> chunks); 680 used
> pg_amop_opr_fam_index: 1024 total in 1 blocks; 240 free (0
> chunks); 784 used
> pg_ts_dict_dictname_index: 1024 total in 1 blocks; 280 free (0
> chunks); 744 used
> pg_auth_members_role_member_index: 1024 total in 1 blocks; 280
> free (0 chunks); 744 used
> pg_type_typname_nsp_index: 1024 total in 1 blocks; 240 free (0
> chunks); 784 used
> pg_opfamily_oid_index: 1024 total in 1 blocks; 344 free (0
> chunks); 680 used
> pg_class_oid_index: 1024 total in 1 blocks; 304 free (0
> chunks); 720 used
> pg_proc_proname_args_nsp_index: 1024 total in 1 blocks; 152
> free (0 chunks); 872 used
> pg_attribute_relid_attnum_index: 1024 total in 1 blocks; 240
> free (0 chunks); 784 used
> pg_proc_oid_index: 1024 total in 1 blocks; 304 free (0 chunks);
> 720 used
> pg_language_oid_index: 1024 total in 1 blocks; 344 free (0
> chunks); 680 used
> pg_namespace_oid_index: 1024 total in 1 blocks; 344 free (0
> chunks); 680 used
> pg_database_oid_index: 1024 total in 1 blocks; 304 free (0
> chunks); 720 used
> pg_amproc_fam_proc_index: 1024 total in 1 blocks; 88 free (0
> chunks); 936 used
> pg_authid_rolname_index: 1024 total in 1 blocks; 304 free (0
> chunks); 720 used
> pg_foreign_server_name_index: 1024 total in 1 blocks; 344 free
> (0 chunks); 680 used
> pg_attribute_relid_attnam_index: 1024 total in 1 blocks; 240
> free (0 chunks); 784 used
> pg_conversion_oid_index: 1024 total in 1 blocks; 344 free (0
> chunks); 680 used
> pg_user_mapping_user_server_index: 1024 total in 1 blocks; 280
> free (0 chunks); 744 used
> pg_conversion_name_nsp_index: 1024 total in 1 blocks; 280 free
> (0 chunks); 744 used
> MdSmgr: 8192 total in 1 blocks; 4240 free (0 chunks); 3952 used
> LOCALLOCK hash: 8192 total in 1 blocks; 3912 free (0 chunks);
> 4280 used
> Timezones: 79320 total in 2 blocks; 5968 free (0 chunks); 73352 used
> ErrorContext: 8192 total in 1 blocks; 8176 free (0 chunks); 16 used
> 2012-03-25 17:18:01 EDT ERROR: out of memory
> 2012-03-25 17:18:01 EDT DETAIL: Failed on request of size 20.
> 2012-03-25 17:18:01 EDT STATEMENT: select loid, max(pageno) from
> ldata group by loid order by 2 desc limit 10;
>
>
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