错误1
FATAL: connection limit exceeded for non-superusers
原因：非超级用户的连接数（max_connections - superuser_reserved_connections）超过了设定值
解决办法：增加max_connections设定值，但如果增加了过多的话，数据库负担太大还容易产生内存错误。可以记住pg-pool等工具来辅助解决。
错误2
FATAL: sorry, too many clients already
原因：数据库服务器的连接数超过了max_connections设定值。
解决办法：和错误1解决办法类似。
错误3
LOG: checkpoints are occurring too frequently
原因：checkpoint处理正频繁发生。
解决办法：增加checkpoint_segments的值。
错误4
LOG: archive command failed with exit code (X)
原因：archive_command 失败了。
解决办法：因为有可能是硬盘没空间了，所以可以把数据库的log删除一些。
错误5
LOG: number of page slots needed (X) exceeds max_fsm_pages (Y)
原因：max_fsm_pages不足了。
解决办法：增加max_fsm_pages的同时进行 VACUUM FULL。
错误6
ERROR: current transaction is aborted, commands ignored until end of transaction blockp
原因：数据库操作时，前一次操作中已经发生过错误了。
解决办法：PostgreSQL包級：ERROR: current transaction is aborted, commands ignored until end of transaction blockp
错误7
ERROR: operator does not exist: character = integer
原因：PostgreSQL8.3以后，取消了默认类型转换。因此需要使比较的类型保持一致。可以看cast函数。
附录：Table A-1. PostgreSQL Error Codes
| Error Code | Condition Name |
|---|---|
| Class 00 — Successful Completion | |
| 00000 | successful_completion |
| Class 01 — Warning | |
| 01000 | warning |
| 0100C | dynamic_result_sets_returned |
| 01008 | implicit_zero_bit_padding |
| 01003 | null_value_eliminated_in_set_function |
| 01007 | privilege_not_granted |
| 01006 | privilege_not_revoked |
| 01004 | string_data_right_truncation |
| 01P01 | deprecated_feature |
| Class 02 — No Data (this is also a warning class per the SQL standard) | |
| 02000 | no_data |
| 02001 | no_additional_dynamic_result_sets_returned |
| Class 03 — SQL Statement Not Yet Complete | |
| 03000 | sql_statement_not_yet_complete |
| Class 08 — Connection Exception | |
| 08000 | connection_exception |
| 08003 | connection_does_not_exist |
| 08006 | connection_failure |
| 08001 | sqlclient_unable_to_establish_sqlconnection |
| 08004 | sqlserver_rejected_establishment_of_sqlconnection |
| 08007 | transaction_resolution_unknown |
| 08P01 | protocol_violation |
| Class 09 — Triggered Action Exception | |
| 09000 | triggered_action_exception |
| Class 0A — Feature Not Supported | |
| 0A000 | feature_not_supported |
| Class 0B — Invalid Transaction Initiation | |
| 0B000 | invalid_transaction_initiation |
| Class 0F — Locator Exception | |
| 0F000 | locator_exception |
| 0F001 | invalid_locator_specification |
| Class 0L — Invalid Grantor | |
| 0L000 | invalid_grantor |
| 0LP01 | invalid_grant_operation |
| Class 0P — Invalid Role Specification | |
| 0P000 | invalid_role_specification |
| Class 0Z — Diagnostics Exception | |
| 0Z000 | diagnostics_exception |
| 0Z002 | stacked_diagnostics_accessed_without_active_handler |
| Class 20 — Case Not Found | |
| 20000 | case_not_found |
| Class 21 — Cardinality Violation | |
| 21000 | cardinality_violation |
| Class 22 — Data Exception | |
| 22000 | data_exception |
| 2202E | array_subscript_error |
| 22021 | character_not_in_repertoire |
| 22008 | datetime_field_overflow |
| 22012 | division_by_zero |
| 22005 | error_in_assignment |
| 2200B | escape_character_conflict |
| 22022 | indicator_overflow |
| 22015 | interval_field_overflow |
| 2201E | invalid_argument_for_logarithm |
| 22014 | invalid_argument_for_ntile_function |
| 22016 | invalid_argument_for_nth_value_function |
| 2201F | invalid_argument_for_power_function |
| 2201G | invalid_argument_for_width_bucket_function |
| 22018 | invalid_character_value_for_cast |
| 22007 | invalid_datetime_format |
| 22019 | invalid_escape_character |
| 2200D | invalid_escape_octet |
| 22025 | invalid_escape_sequence |
| 22P06 | nonstandard_use_of_escape_character |
| 22010 | invalid_indicator_parameter_value |
| 22023 | invalid_parameter_value |
| 2201B | invalid_regular_expression |
| 2201W | invalid_row_count_in_limit_clause |
| 2201X | invalid_row_count_in_result_offset_clause |
| 2202H | invalid_tablesample_argument |
| 2202G | invalid_tablesample_repeat |
| 22009 | invalid_time_zone_displacement_value |
| 2200C | invalid_use_of_escape_character |
| 2200G | most_specific_type_mismatch |
| 22004 | null_value_not_allowed |
| 22002 | null_value_no_indicator_parameter |
| 22003 | numeric_value_out_of_range |
| 22026 | string_data_length_mismatch |
| 22001 | string_data_right_truncation |
| 22011 | substring_error |
| 22027 | trim_error |
| 22024 | unterminated_c_string |
| 2200F | zero_length_character_string |
| 22P01 | floating_point_exception |
| 22P02 | invalid_text_representation |
| 22P03 | invalid_binary_representation |
| 22P04 | bad_copy_file_format |
| 22P05 | untranslatable_character |
| 2200L | not_an_xml_document |
| 2200M | invalid_xml_document |
| 2200N | invalid_xml_content |
| 2200S | invalid_xml_comment |
| 2200T | invalid_xml_processing_instruction |
| Class 23 — Integrity Constraint Violation | |
| 23000 | integrity_constraint_violation |
| 23001 | restrict_violation |
| 23502 | not_null_violation |
| 23503 | foreign_key_violation |
| 23505 | unique_violation |
| 23514 | check_violation |
| 23P01 | exclusion_violation |
| Class 24 — Invalid Cursor State | |
| 24000 | invalid_cursor_state |
| Class 25 — Invalid Transaction State | |
| 25000 | invalid_transaction_state |
| 25001 | active_sql_transaction |
| 25002 | branch_transaction_already_active |
| 25008 | held_cursor_requires_same_isolation_level |
| 25003 | inappropriate_access_mode_for_branch_transaction |
| 25004 | inappropriate_isolation_level_for_branch_transaction |
| 25005 | no_active_sql_transaction_for_branch_transaction |
| 25006 | read_only_sql_transaction |
| 25007 | schema_and_data_statement_mixing_not_supported |
| 25P01 | no_active_sql_transaction |
| 25P02 | in_failed_sql_transaction |
| Class 26 — Invalid SQL Statement Name | |
| 26000 | invalid_sql_statement_name |
| Class 27 — Triggered Data Change Violation | |
| 27000 | triggered_data_change_violation |
| Class 28 — Invalid Authorization Specification | |
| 28000 | invalid_authorization_specification |
| 28P01 | invalid_password |
| Class 2B — Dependent Privilege Descriptors Still Exist | |
| 2B000 | dependent_privilege_descriptors_still_exist |
| 2BP01 | dependent_objects_still_exist |
| Class 2D — Invalid Transaction Termination | |
| 2D000 | invalid_transaction_termination |
| Class 2F — SQL Routine Exception | |
| 2F000 | sql_routine_exception |
| 2F005 | function_executed_no_return_statement |
| 2F002 | modifying_sql_data_not_permitted |
| 2F003 | prohibited_sql_statement_attempted |
| 2F004 | reading_sql_data_not_permitted |
| Class 34 — Invalid Cursor Name | |
| 34000 | invalid_cursor_name |
| Class 38 — External Routine Exception | |
| 38000 | external_routine_exception |
| 38001 | containing_sql_not_permitted |
| 38002 | modifying_sql_data_not_permitted |
| 38003 | prohibited_sql_statement_attempted |
| 38004 | reading_sql_data_not_permitted |
| Class 39 — External Routine Invocation Exception | |
| 39000 | external_routine_invocation_exception |
| 39001 | invalid_sqlstate_returned |
| 39004 | null_value_not_allowed |
| 39P01 | trigger_protocol_violated |
| 39P02 | srf_protocol_violated |
| 39P03 | event_trigger_protocol_violated |
| Class 3B — Savepoint Exception | |
| 3B000 | savepoint_exception |
| 3B001 | invalid_savepoint_specification |
| Class 3D — Invalid Catalog Name | |
| 3D000 | invalid_catalog_name |
| Class 3F — Invalid Schema Name | |
| 3F000 | invalid_schema_name |
| Class 40 — Transaction Rollback | |
| 40000 | transaction_rollback |
| 40002 | transaction_integrity_constraint_violation |
| 40001 | serialization_failure |
| 40003 | statement_completion_unknown |
| 40P01 | deadlock_detected |
| Class 42 — Syntax Error or Access Rule Violation | |
| 42000 | syntax_error_or_access_rule_violation |
| 42601 | syntax_error |
| 42501 | insufficient_privilege |
| 42846 | cannot_coerce |
| 42803 | grouping_error |
| 42P20 | windowing_error |
| 42P19 | invalid_recursion |
| 42830 | invalid_foreign_key |
| 42602 | invalid_name |
| 42622 | name_too_long |
| 42939 | reserved_name |
| 42804 | datatype_mismatch |
| 42P18 | indeterminate_datatype |
| 42P21 | collation_mismatch |
| 42P22 | indeterminate_collation |
| 42809 | wrong_object_type |
| 42703 | undefined_column |
| 42883 | undefined_function |
| 42P01 | undefined_table |
| 42P02 | undefined_parameter |
| 42704 | undefined_object |
| 42701 | duplicate_column |
| 42P03 | duplicate_cursor |
| 42P04 | duplicate_database |
| 42723 | duplicate_function |
| 42P05 | duplicate_prepared_statement |
| 42P06 | duplicate_schema |
| 42P07 | duplicate_table |
| 42712 | duplicate_alias |
| 42710 | duplicate_object |
| 42702 | ambiguous_column |
| 42725 | ambiguous_function |
| 42P08 | ambiguous_parameter |
| 42P09 | ambiguous_alias |
| 42P10 | invalid_column_reference |
| 42611 | invalid_column_definition |
| 42P11 | invalid_cursor_definition |
| 42P12 | invalid_database_definition |
| 42P13 | invalid_function_definition |
| 42P14 | invalid_prepared_statement_definition |
| 42P15 | invalid_schema_definition |
| 42P16 | invalid_table_definition |
| 42P17 | invalid_object_definition |
| Class 44 — WITH CHECK OPTION Violation | |
| 44000 | with_check_option_violation |
| Class 53 — Insufficient Resources | |
| 53000 | insufficient_resources |
| 53100 | disk_full |
| 53200 | out_of_memory |
| 53300 | too_many_connections |
| 53400 | configuration_limit_exceeded |
| Class 54 — Program Limit Exceeded | |
| 54000 | program_limit_exceeded |
| 54001 | statement_too_complex |
| 54011 | too_many_columns |
| 54023 | too_many_arguments |
| Class 55 — Object Not In Prerequisite State | |
| 55000 | object_not_in_prerequisite_state |
| 55006 | object_in_use |
| 55P02 | cant_change_runtime_param |
| 55P03 | lock_not_available |
| Class 57 — Operator Intervention | |
| 57000 | operator_intervention |
| 57014 | query_canceled |
| 57P01 | admin_shutdown |
| 57P02 | crash_shutdown |
| 57P03 | cannot_connect_now |
| 57P04 | database_dropped |
| Class 58 — System Error (errors external to PostgreSQL itself) | |
| 58000 | system_error |
| 58030 | io_error |
| 58P01 | undefined_file |
| 58P02 | duplicate_file |
| Class F0 — Configuration File Error | |
| F0000 | config_file_error |
| F0001 | lock_file_exists |
| Class HV — Foreign Data Wrapper Error (SQL/MED) | |
| HV000 | fdw_error |
| HV005 | fdw_column_name_not_found |
| HV002 | fdw_dynamic_parameter_value_needed |
| HV010 | fdw_function_sequence_error |
| HV021 | fdw_inconsistent_descriptor_information |
| HV024 | fdw_invalid_attribute_value |
| HV007 | fdw_invalid_column_name |
| HV008 | fdw_invalid_column_number |
| HV004 | fdw_invalid_data_type |
| HV006 | fdw_invalid_data_type_descriptors |
| HV091 | fdw_invalid_descriptor_field_identifier |
| HV00B | fdw_invalid_handle |
| HV00C | fdw_invalid_option_index |
| HV00D | fdw_invalid_option_name |
| HV090 | fdw_invalid_string_length_or_buffer_length |
| HV00A | fdw_invalid_string_format |
| HV009 | fdw_invalid_use_of_null_pointer |
| HV014 | fdw_too_many_handles |
| HV001 | fdw_out_of_memory |
| HV00P | fdw_no_schemas |
| HV00J | fdw_option_name_not_found |
| HV00K | fdw_reply_handle |
| HV00Q | fdw_schema_not_found |
| HV00R | fdw_table_not_found |
| HV00L | fdw_unable_to_create_execution |
| HV00M | fdw_unable_to_create_reply |
| HV00N | fdw_unable_to_establish_connection |
| Class P0 — PL/pgSQL Error | |
| P0000 | plpgsql_error |
| P0001 | raise_exception |
| P0002 | no_data_found |
| P0003 | too_many_rows |
| P0004 | assert_failure |
| Class XX — Internal Error | |
| XX000 | internal_error |
| XX001 | data_corrupted |
| XX002 | index_corrupted |