来阿里云之前，做的一些RDS测试。
几个月过去了，阿里云RDS PG在性能方面做出了大量的代码层优化，感兴趣的童鞋赶紧测试，来PK我之前的测试数据吧。
测试机申请的RDS都是最低配置的，容量5GB，内存1GB，支持100个连接，IOPS 400。
先看看配置吧，为了提高性能，有一些参数是可以调整的，如下：
postgres=> select name,substring(setting,1,10),unit from pg_settings order by category, name;
name | substring | unit
-------------------------------------+---------------------------+------
autovacuum | on |
autovacuum_analyze_scale_factor | 0.1 |
autovacuum_analyze_threshold | 50 |
autovacuum_freeze_max_age | 200000000 |
autovacuum_max_workers | 5 |
autovacuum_multixact_freeze_max_age | 400000000 |
autovacuum_naptime | 60 | s
autovacuum_vacuum_cost_delay | 0 | ms
autovacuum_vacuum_cost_limit | -1 |
autovacuum_vacuum_scale_factor | 0.1 |
autovacuum_vacuum_threshold | 50 |
client_encoding | UTF8 |
DateStyle | ISO, YMD |
default_text_search_config | pg_catalog |
extra_float_digits | 0 |
IntervalStyle | postgres |
lc_collate | zh_CN.UTF- | -- 个人建议LC相关的全部改为C，并且数据库初始化时也建议选C
lc_ctype | zh_CN.UTF- |
lc_messages | C |
lc_monetary | zh_CN.UTF- |
lc_numeric | zh_CN.UTF- |
lc_time | zh_CN.UTF- |
server_encoding | UTF8 |
TimeZone | PRC |
timezone_abbreviations | Default |
gin_fuzzy_search_limit | 0 |
tcp_keepalives_count | 9 |
tcp_keepalives_idle | 7200 | s -- 建议改小，例如60，如果有跨广域网访问的话。
tcp_keepalives_interval | 75 | s -- 建议改小
local_preload_libraries | |
bytea_output | hex |
check_function_bodies | on |
default_tablespace | |
default_transaction_deferrable | off |
default_transaction_isolation | read commi |
default_transaction_read_only | off |
lock_timeout | 0 | ms -- 建议用户针对自己的业务，修改锁等待超时
search_path | "$user",pu |
session_replication_role | origin |
statement_timeout | 0 | ms -- 建议用户针对自己的业务，修改语句执行超时
temp_tablespaces | |
transaction_deferrable | off |
transaction_isolation | read commi |
transaction_read_only | off |
vacuum_freeze_min_age | 50000000 |
vacuum_freeze_table_age | 150000000 |
vacuum_multixact_freeze_min_age | 5000000 |
vacuum_multixact_freeze_table_age | 150000000 |
xmlbinary | base64 |
xmloption | content |
bonjour | off |
bonjour_name | |
listen_addresses | * |
max_connections | 100 |
port | 3009 | -- 这是数据库的监听端口，和RDS提供的端口不一样，因为RDS用了SLB
superuser_reserved_connections | 10 | -- 为超级用户保留的连接，阿里云管理RDS用的，超级用户对客户不开放
unix_socket_group | |
unix_socket_permissions | 0777 | -- 这个权限改为0700更靠谱，交给阿里云来修改。
authentication_timeout | 60 | s
db_user_namespace | off |
krb_caseins_users | off |
password_encryption | on |
ssl | off | -- 对于跨广域网的访问，建议阿里云允许SSL连接，交给阿里云来支持。
ssl_ca_file | |
ssl_cert_file | server.crt |
ssl_crl_file | |
ssl_key_file | server.key |
ssl_prefer_server_ciphers | on |
ssl_renegotiation_limit | 524288 | kB
pg_stat_statements.max | 1000 | -- 阿里云RDS默认开启了pg_stat_statements
pg_stat_statements.save | on |
pg_stat_statements.track | all |
pg_stat_statements.track_utility | on |
allow_system_table_mods | off |
debug_assertions | off |
ignore_checksum_failure | off |
ignore_system_indexes | off |
post_auth_delay | 0 | s
pre_auth_delay | 0 | s
trace_notify | off |
trace_recovery_messages | log |
trace_sort | off |
zero_damaged_pages | off |
exit_on_error | off |
restart_after_crash | on |
deadlock_timeout | 1000 | ms -- 锁时间超过1秒，记录锁等待SQL以及其他状态
max_locks_per_transaction | 64 |
max_pred_locks_per_transaction | 64 |
block_size | 8192 | -- 建议改为用户可选择的块大小，对于有大批量数据导入的应用建议大块。当然这里还涉及FPW，shared buffer空间利用率。
data_checksums | on | -- checksums打开，对性能有一定影响，开启了FULL PAGE WRITE一般没有必要开这个。但另一方面体现了阿里云PG的可靠性第一的理念。
integer_datetimes | on |
max_function_args | 100 |
max_identifier_length | 63 |
max_index_keys | 32 |
segment_size | 131072 | 8kB -- 单个数据文件最大1GB
server_version | 9.4.1 |
server_version_num | 90401 |
wal_block_size | 8192 |
wal_segment_size | 2048 | 8kB -- 单个WAL文件16MB
geqo | on |
geqo_effort | 5 |
geqo_generations | 0 |
geqo_pool_size | 0 |
geqo_seed | 0 |
geqo_selection_bias | 2 |
geqo_threshold | 12 | -- 超过12个对象的JOIN会使用遗传优化算法，不用穷举法
constraint_exclusion | partition |
cursor_tuple_fraction | 0.1 |
default_statistics_target | 100 |
from_collapse_limit | 8 |
join_collapse_limit | 8 |
cpu_index_tuple_cost | 0.005 | -- 成本因子，不知道阿里有没有针对硬件环境调整，看样子是没有调整
cpu_operator_cost | 0.0025 |
cpu_tuple_cost | 0.01 |
effective_cache_size | 98304 | 8kB
random_page_cost | 4 |
seq_page_cost | 1 |
enable_bitmapscan | on |
enable_hashagg | on |
enable_hashjoin | on |
enable_indexonlyscan | on |
enable_indexscan | on |
enable_material | on |
enable_mergejoin | on |
enable_nestloop | on |
enable_seqscan | on |
enable_sort | on |
enable_tidscan | on |
synchronous_standby_names | | -- 未开启同步流复制
vacuum_defer_cleanup_age | 0 |
max_replication_slots | 10 |
max_wal_senders | 5 |
wal_keep_segments | 80 |
wal_sender_timeout | 60000 | ms
hot_standby | on | -- 开启了hot_standby，用于HA。
hot_standby_feedback | on |
max_standby_archive_delay | 30000 | ms -- 如果将来阿里云要开放读写分离，在SLAVE要跑LONG SQL的话，可能要加大这个值
max_standby_streaming_delay | 30000 | ms -- 如果将来阿里云要开放读写分离，在SLAVE要跑LONG SQL的话，可能要加大这个值
wal_receiver_status_interval | 10 | s -- 建议缩短feedback时延
wal_receiver_timeout | 60000 | ms
application_name | psql |
debug_pretty_print | on |
debug_print_parse | off |
debug_print_plan | off |
debug_print_rewritten | off |
log_autovacuum_min_duration | -1 | ms -- 这个值建议改为0，记录所有的垃圾回收操作
log_checkpoints | off | -- 建议打开
log_connections | off | -- 建议打开
log_disconnections | off | -- 建议打开
log_duration | off |
log_error_verbosity | default | -- 建议改为 verbose, 记录代码位置
log_hostname | off |
log_line_prefix | \x01 +|
| %p %r % |
log_lock_waits | on |
log_statement | all | -- 又一个对性能有影响的参数，审计所有SQL，当然这里代码层有优化的余地，所以性能影响可以做到很小。
log_temp_files | 100000 | kB
log_timezone | UTC |
client_min_messages | notice |
log_min_duration_statement | 1000 | ms -- 开了log_statement=all, 这个就没有必要了。
log_min_error_statement | error |
log_min_messages | warning |
event_source | PostgreSQL |
log_destination | stderr | -- 建议使用csvlog，或者加一个remote log。日志统一发到监控平台。
log_file_mode | 0600 |
logging_collector | on |
log_rotation_age | 0 | min
log_rotation_size | 10240 | kB
log_truncate_on_rotation | on |
syslog_facility | local0 |
syslog_ident | postgres |
effective_io_concurrency | 1 |
max_worker_processes | 8 |
bgwriter_delay | 20 | ms
bgwriter_lru_maxpages | 100 |
bgwriter_lru_multiplier | 2 |
vacuum_cost_delay | 0 | ms -- 如果想降低垃圾回收对IO的影响，可以改为10毫秒，但是垃圾回收的时间会拉长
vacuum_cost_limit | 200 |
vacuum_cost_page_dirty | 20 |
vacuum_cost_page_hit | 1 |
vacuum_cost_page_miss | 10 |
temp_file_limit | -1 | kB
max_files_per_process | 1000 |
autovacuum_work_mem | -1 | kB
dynamic_shared_memory_type | posix |
huge_pages | try |
maintenance_work_mem | 16384 | kB
max_prepared_transactions | 800 | -- 允许用户使用分布式事务，一般不建议打开，对于不熟悉的用户，可能导致膨胀，xid wrap等不良后果。除非有使用的必要。
max_stack_depth | 2048 | kB
shared_buffers | 32768 | 8kB -- 不同规格，会设置不同的shared buffer大小，一般为规格内存的1/4.
temp_buffers | 1024 | 8kB
track_activity_query_size | 1024 |
work_mem | 4096 | kB
log_executor_stats | off |
log_parser_stats | off |
log_planner_stats | off |
log_statement_stats | off |
track_activities | on |
track_counts | on |
track_functions | all | -- 这个也是对性能有影响的，统计所有的函数调用，为了更好的展示性能指标.
track_io_timing | on | -- 对IO耗时进行统计，相当影响性能
update_process_title | on |
transform_null_equals | off |
array_nulls | on |
backslash_quote | safe_encod |
default_with_oids | off |
escape_string_warning | on |
lo_compat_privileges | off |
quote_all_identifiers | off |
sql_inheritance | on |
standard_conforming_strings | on |
synchronize_seqscans | on |
archive_command | cp %p /u02 |
archive_mode | on | -- 开启了归档，是为了更好的做在线备份
archive_timeout | 0 | s
checkpoint_completion_target | 0.9 | -- 检查点的时间拉这么长，主要是为了减少检查点带来的锯齿，阿里云RDS PG已经改进了检查点的性能影响，代码层。
checkpoint_segments | 64 | -- shared buffer只有256MB，但是这个有1GB的间隔，可以考虑加大shared buffer。前提是cgroup不会限制。
checkpoint_timeout | 300 | s
checkpoint_warning | 30 | s
commit_delay | 0 | -- 未开启分组提交，对于高并发的场景，建议打开。当然也可以关闭synchronous_commit 达到同样的目的。
commit_siblings | 5 |
fsync | on |
full_page_writes | on | -- 如果底层块设备的原子写大于等于block_size，和wal_block_size，可以关闭full_page_writes, 或者底层文件系统可以避免partial write，也可以关闭fpw.
synchronous_commit | on | -- 对于非重要事务，建议在事务级别关闭synchronous_commit 来提高性能。
wal_buffers | 983 | 8kB
wal_level | hot_standb |
wal_log_hints | off |
wal_sync_method | fdatasync | -- 建议根据wal所在的块设备测试一下，使用最快的fsync接口，fdatasync刷data page, 不刷inode。
wal_writer_delay | 200 | ms -- 建议改为10ms
(228 rows)
以上有很多可以优化或调整的地方，希望阿里云RDS团队的人看到或者用户看到，大家一起来把RDS搞好，用好。
接下来先做一个简单的单个实例的性能测试，因为RDS实例是最低配置的，而且鉴于以上配置有些对性能影响较大的，同时网络层面不是直连数据库，因为阿里云里面还有一层中间件，另外还有一个对性能有影响的是用了其他机房的ECS去测试RDS，所以结果可能和我们自己笔记本上测试的都相差甚远。
请看：
生成测试数据，为了减少IOPS，因为CGROUP限制了只有400的IOPS，所以我们的测试数据和索引加起来要小于256MB，用户数据200万条，会话数据200万条，一共400万条初始数据，以及日志表一个。
\timing
set synchronous_commit=off;
create table userinfo (userid int,info jsonb);
insert into userinfo select generate_series(1,2000000);
create table session (userid int,last_login timestamp);
insert into session select generate_series(1,2000000);
create table login_log (userid int,db_user name,client_addr inet,
client_port int,server_addr inet,server_port int,login_time timestamp);
set maintenance_work_mem='1GB';
alter table userinfo add constraint pk_userinfo primary key (userid);
alter table session add constraint pk_session primary key (userid);
postgres=> \dt+
List of relations
Schema | Name | Type | Owner | Size | Description
--------+-----------------+-------+--------+--------+-------------
public | ha_health_check | table | aurora | 40 kB |
public | login_log | table | digoal | 141 MB |
public | session | table | digoal | 75 MB |
public | userinfo | table | digoal | 69 MB |
(4 rows)
postgres=> \di+
List of relations
Schema | Name | Type | Owner | Table | Size | Description
--------+----------------------+-------+--------+-----------------+-------+-------------
public | ha_health_check_pkey | index | aurora | ha_health_check | 16 kB |
public | login_log_pkey | index | digoal | login_log | 22 MB |
public | pk_session | index | digoal | session | 43 MB |
public | pk_userinfo | index | digoal | userinfo | 43 MB |
(4 rows)
将数据加载到内存：
create extension pg_prewarm;
select pg_prewarm('userinfo');
select pg_prewarm('pk_userinfo');
select pg_prewarm('session');
select pg_prewarm('pk_session');
创建测试函数，包含3个操作：
1. 基于PK执行查询用户表，
2. 基于PK更新会话表，
3. 插入日志
共三个操作的事务，使用异步提交。
create or replace function f_test(i_id int) returns void as
$$
declare
v_t timestamp := now();
begin
set synchronous_commit = off;
perform 1 from userinfo where userid=i_id;
update session set last_login=v_t where userid=i_id;
insert into login_log (userid,db_user,client_addr,client_port,server_addr,server_port,login_time)
values (i_id,current_user,inet_client_addr(),inet_client_port(),inet_server_addr(),inet_server_port(),v_t);
return;
end;
$$
language plpgsql strict;
验证：
postgres=> select f_test(1);
f_test
--------
(1 row)
postgres=> select now(),* from session where userid=1;
now | userid | last_login
-------------------------------+--------+---------------------------
2015-06-10 11:44:01.820262+08 | 1 | 2015-06-10 11:44:01.22805
(1 row)
测试机是阿里云的ECS（1核的ECS，也是较烂的性能了），与数据库在北京的不同机房（因为没找到同机房的ECS），测试：
vi test.sql
\setrandom id 1 2000000
select f_test(:id);
测试5分钟，每5秒输出一次tps统计，测试结果：
pgbench -M prepared -n -r -f ./test.sql -c 16 -j 16 -P 5 -h xxxx -p 3433 -U digoal -T 300 postgres
progress: 5.0 s, 2903.1 tps, lat 5.482 ms stddev 7.189
progress: 10.0 s, 3101.8 tps, lat 5.162 ms stddev 6.366
progress: 15.0 s, 3131.1 tps, lat 5.098 ms stddev 6.286
progress: 20.0 s, 3060.6 tps, lat 5.234 ms stddev 6.591
progress: 25.0 s, 3198.8 tps, lat 4.998 ms stddev 6.069
progress: 30.0 s, 3110.7 tps, lat 5.144 ms stddev 6.362
progress: 35.0 s, 2972.9 tps, lat 5.376 ms stddev 6.899
progress: 40.0 s, 3060.7 tps, lat 5.224 ms stddev 6.609
progress: 45.0 s, 3057.8 tps, lat 5.232 ms stddev 6.642
progress: 50.0 s, 3051.0 tps, lat 5.242 ms stddev 6.601
progress: 55.0 s, 3083.9 tps, lat 5.192 ms stddev 6.454
progress: 60.0 s, 3154.5 tps, lat 5.063 ms stddev 6.247
progress: 65.0 s, 3103.8 tps, lat 5.166 ms stddev 6.421
progress: 70.0 s, 3099.7 tps, lat 5.158 ms stddev 6.464
progress: 75.0 s, 3141.9 tps, lat 5.092 ms stddev 6.292
progress: 80.0 s, 3105.9 tps, lat 5.140 ms stddev 6.406
progress: 85.0 s, 3097.7 tps, lat 5.161 ms stddev 6.412
progress: 90.0 s, 3112.3 tps, lat 5.146 ms stddev 6.339
progress: 95.0 s, 3023.9 tps, lat 5.271 ms stddev 6.627
progress: 100.0 s, 3088.4 tps, lat 5.194 ms stddev 6.426
progress: 105.0 s, 3095.3 tps, lat 5.178 ms stddev 6.358
progress: 110.0 s, 3085.7 tps, lat 5.172 ms stddev 6.465
progress: 115.0 s, 3143.2 tps, lat 5.099 ms stddev 6.185
progress: 122.9 s, 1429.7 tps, lat 6.803 ms stddev 78.508
progress: 127.8 s, 174.7 tps, lat 95.927 ms stddev 617.430
progress: 130.5 s, 443.2 tps, lat 61.379 ms stddev 460.493
progress: 135.5 s, 240.0 tps, lat 68.903 ms stddev 379.392
progress: 143.0 s, 179.9 tps, lat 45.773 ms stddev 314.194
progress: 148.1 s, 330.8 tps, lat 74.456 ms stddev 564.188
progress: 150.2 s, 993.0 tps, lat 20.515 ms stddev 249.150
progress: 158.5 s, 265.6 tps, lat 58.506 ms stddev 422.513
progress: 160.3 s, 1535.6 tps, lat 15.287 ms stddev 188.301
progress: 168.8 s, 377.9 tps, lat 34.676 ms stddev 309.978
progress: 170.0 s, 2758.9 tps, lat 15.764 ms stddev 204.179
progress: 175.0 s, 992.6 tps, lat 16.132 ms stddev 146.747
progress: 180.0 s, 1061.1 tps, lat 15.093 ms stddev 136.797
progress: 185.0 s, 487.3 tps, lat 32.812 ms stddev 302.795
progress: 190.8 s, 1665.7 tps, lat 6.174 ms stddev 57.000
progress: 195.7 s, 834.5 tps, lat 16.647 ms stddev 189.034
progress: 204.2 s, 1839.9 tps, lat 10.975 ms stddev 147.814
progress: 205.0 s, 3180.3 tps, lat 8.171 ms stddev 95.892
progress: 210.0 s, 3216.4 tps, lat 4.972 ms stddev 10.054
progress: 215.0 s, 1229.4 tps, lat 13.029 ms stddev 166.420
progress: 220.0 s, 3178.3 tps, lat 5.039 ms stddev 7.517
progress: 225.0 s, 3261.0 tps, lat 4.897 ms stddev 11.573
progress: 230.0 s, 3149.3 tps, lat 5.073 ms stddev 7.657
progress: 235.0 s, 3200.8 tps, lat 4.995 ms stddev 7.128
progress: 240.0 s, 3128.6 tps, lat 5.121 ms stddev 9.665
progress: 245.0 s, 3063.0 tps, lat 5.223 ms stddev 6.571
progress: 250.0 s, 3047.3 tps, lat 5.250 ms stddev 6.514
progress: 255.0 s, 3192.3 tps, lat 5.007 ms stddev 6.121
progress: 260.0 s, 3113.3 tps, lat 5.148 ms stddev 6.379
progress: 265.0 s, 3278.1 tps, lat 4.871 ms stddev 5.762
progress: 270.0 s, 3091.6 tps, lat 5.181 ms stddev 6.378
progress: 275.0 s, 3172.2 tps, lat 5.034 ms stddev 6.098
progress: 280.0 s, 2879.8 tps, lat 5.556 ms stddev 7.319
progress: 285.0 s, 3267.2 tps, lat 4.900 ms stddev 5.850
progress: 290.0 s, 3174.6 tps, lat 5.035 ms stddev 6.097
progress: 295.0 s, 3201.1 tps, lat 4.996 ms stddev 6.033
progress: 300.0 s, 3071.6 tps, lat 5.216 ms stddev 6.439
transaction type: Custom query
scaling factor: 1
query mode: prepared
number of clients: 16
number of threads: 16
duration: 300 s
number of transactions actually processed: 720287
latency average: 6.663 ms
latency stddev: 72.356 ms
tps = 2400.926759 (including connections establishing)
tps = 2401.013184 (excluding connections establishing)
statement latencies in milliseconds:
0.002118 \setrandom id 1 2000000
6.659889 select f_test(:id);
性能抖动分析，虽然拿不到数据库的日志，但是基本上判断和检查点有关，检查点时会产生刷脏数据的IO，因此更新会变慢，同时又开启了FPW，所以接下来的脏块写WAL BUFFER开销会变大，所以性能抖动严重，这个是需要优化的，但是IOPS是无法优化的硬伤。详见我以前写的一些分析文章：
http://blog.163.com/digoal@126/blog/static/163877040201542103933969/
http://blog.163.com/digoal@126/blog/static/1638770402015463252387/
http://blog.163.com/digoal@126/blog/static/16387704020154651655783/
http://blog.163.com/digoal@126/blog/static/16387704020154653422892/
http://blog.163.com/digoal@126/blog/static/16387704020154811421484/
http://blog.163.com/digoal@126/blog/static/16387704020154129958753/
所以我们再看看不带更新, 只有查询和插入的测试吧：
create or replace function f_test(i_id int) returns void as
$$
declare
v_t timestamp := now();
begin
set synchronous_commit = off;
perform 1 from userinfo where userid=i_id;
-- update session set last_login=v_t where userid=i_id;
insert into login_log (userid,db_user,client_addr,client_port,server_addr,server_port,login_time)
values (i_id,current_user,inet_client_addr(),inet_client_port(),inet_server_addr(),inet_server_port(),v_t);
return;
end;
$$
language plpgsql strict;
测试结果，性能相当平稳：
pgbench -M prepared -n -r -f ./test.sql -c 16 -j 16 -P 5 -h xxxx -p 3433 -U digoal -T 300 postgres
progress: 5.0 s, 3571.7 tps, lat 4.466 ms stddev 4.847
progress: 10.0 s, 3653.7 tps, lat 4.379 ms stddev 4.484
progress: 15.0 s, 3675.6 tps, lat 4.352 ms stddev 4.416
progress: 20.0 s, 3688.8 tps, lat 4.337 ms stddev 4.420
progress: 25.0 s, 3766.2 tps, lat 4.247 ms stddev 4.116
progress: 30.0 s, 3626.6 tps, lat 4.411 ms stddev 4.657
progress: 35.0 s, 3683.6 tps, lat 4.342 ms stddev 4.424
progress: 40.0 s, 3735.7 tps, lat 4.282 ms stddev 4.283
progress: 45.0 s, 3818.3 tps, lat 4.189 ms stddev 4.027
progress: 50.0 s, 3736.7 tps, lat 4.281 ms stddev 4.259
progress: 55.0 s, 3763.7 tps, lat 4.250 ms stddev 4.158
progress: 60.0 s, 3768.1 tps, lat 4.245 ms stddev 4.169
progress: 65.0 s, 3699.0 tps, lat 4.324 ms stddev 4.355
progress: 70.0 s, 3698.1 tps, lat 4.326 ms stddev 4.345
progress: 75.0 s, 3653.2 tps, lat 4.378 ms stddev 4.496
progress: 80.0 s, 3623.2 tps, lat 4.415 ms stddev 4.615
progress: 85.0 s, 3653.9 tps, lat 4.378 ms stddev 4.464
progress: 90.0 s, 3548.9 tps, lat 4.507 ms stddev 4.958
progress: 95.0 s, 3656.9 tps, lat 4.374 ms stddev 4.520
progress: 100.0 s, 3750.1 tps, lat 4.265 ms stddev 4.221
progress: 105.0 s, 3742.4 tps, lat 4.274 ms stddev 4.190
progress: 110.0 s, 3662.2 tps, lat 4.368 ms stddev 4.464
progress: 115.0 s, 3652.6 tps, lat 4.379 ms stddev 4.431
progress: 120.0 s, 3707.2 tps, lat 4.315 ms stddev 4.363
progress: 125.0 s, 3765.1 tps, lat 4.248 ms stddev 4.216
progress: 130.0 s, 3750.7 tps, lat 4.265 ms stddev 4.244
progress: 135.0 s, 3693.3 tps, lat 4.331 ms stddev 4.371
progress: 140.0 s, 3748.8 tps, lat 4.267 ms stddev 4.264
progress: 145.0 s, 3702.3 tps, lat 4.320 ms stddev 4.297
progress: 150.0 s, 3584.9 tps, lat 4.462 ms stddev 4.832
progress: 155.0 s, 3537.5 tps, lat 4.522 ms stddev 4.942
progress: 160.0 s, 3638.0 tps, lat 4.397 ms stddev 4.472
progress: 165.0 s, 3645.4 tps, lat 4.388 ms stddev 4.489
progress: 170.0 s, 3642.1 tps, lat 4.392 ms stddev 4.488
progress: 175.0 s, 3650.1 tps, lat 4.382 ms stddev 4.473
progress: 180.0 s, 3550.6 tps, lat 4.505 ms stddev 4.733
progress: 185.0 s, 3550.3 tps, lat 4.505 ms stddev 4.613
progress: 190.0 s, 3703.2 tps, lat 4.319 ms stddev 4.374
progress: 195.0 s, 3666.0 tps, lat 4.363 ms stddev 4.440
progress: 200.0 s, 3660.2 tps, lat 4.371 ms stddev 4.520
progress: 205.0 s, 3686.4 tps, lat 4.339 ms stddev 4.374
progress: 210.0 s, 3557.1 tps, lat 4.497 ms stddev 4.882
progress: 215.0 s, 3546.0 tps, lat 4.505 ms stddev 4.914
progress: 220.0 s, 3726.5 tps, lat 4.298 ms stddev 4.293
progress: 225.0 s, 3740.5 tps, lat 4.276 ms stddev 4.247
progress: 230.0 s, 3704.3 tps, lat 4.318 ms stddev 4.337
progress: 235.0 s, 3635.7 tps, lat 4.400 ms stddev 4.510
progress: 240.0 s, 3592.6 tps, lat 4.453 ms stddev 4.675
progress: 245.0 s, 3581.2 tps, lat 4.466 ms stddev 4.732
progress: 250.0 s, 3609.8 tps, lat 4.431 ms stddev 4.626
progress: 255.0 s, 3628.8 tps, lat 4.408 ms stddev 4.549
progress: 260.0 s, 3611.0 tps, lat 4.430 ms stddev 4.608
progress: 265.0 s, 3666.0 tps, lat 4.363 ms stddev 4.395
progress: 270.0 s, 3657.9 tps, lat 4.373 ms stddev 4.575
progress: 275.0 s, 3603.4 tps, lat 4.439 ms stddev 4.791
progress: 280.0 s, 3794.4 tps, lat 4.215 ms stddev 4.105
progress: 285.0 s, 3759.1 tps, lat 4.255 ms stddev 4.123
progress: 290.0 s, 3631.6 tps, lat 4.405 ms stddev 4.468
progress: 295.0 s, 3741.2 tps, lat 4.275 ms stddev 4.196
progress: 300.0 s, 3743.8 tps, lat 4.273 ms stddev 4.223
transaction type: Custom query
scaling factor: 1
query mode: prepared
number of clients: 16
number of threads: 16
duration: 300 s
number of transactions actually processed: 1101227
latency average: 4.357 ms
latency stddev: 4.453 ms
tps = 3670.717757 (including connections establishing)
tps = 3670.852824 (excluding connections establishing)
statement latencies in milliseconds:
0.002000 \setrandom id 1 2000000
4.354966 select f_test(:id);
小结：
1. RDS内部再优化一下，性能还会更加靠谱。可以参考前面的参数分析。
2. 另外需要注意别触碰到IOPS的瓶颈，因为是用cgroup限制的，影响很大。
3. RDS用了异步流复制，所以用户需要注意，是否有绝对的不丢事务的需求，这点一定要和阿里云确定清楚，如果有，必须要使用同步流复制。
其他：
在阿里云RDS中使用dblink：
CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw OPTIONS (host 'xxxxxx', dbname 'postgres', port '3433');
CREATE USER MAPPING FOR digoal SERVER fdtest OPTIONS (user 'xxx', password 'xxx');
GRANT USAGE ON FOREIGN SERVER fdtest TO digoal;
SELECT dblink_connect('myconn', 'fdtest');
查看数据库的真实IP
postgres=> SELECT * from dblink('myconn', 'select inet_server_addr()') as t(ip inet);
ip
---------------
10.151.133.18
(1 row)
查看客户端的真实IP，从现象上看，至少中间件这层在IP层好像是透明的，或者做了协议适配。
postgres=> SELECT * from dblink('myconn', 'select inet_client_addr()') as t(ip inet);
ip
---------------
10.151.133.19
(1 row)
查看standby状态，普通用户现在了一些信息的查看。
postgres=> select * from pg_stat_replication ;
pid | usesysid | usename | application_name | client_addr | client_hostname | client_port | backend_start | backend_xmin | st
ate | sent_location | write_location | flush_location | replay_location | sync_priority | sync_state
--------+----------+------------+------------------+-------------+-----------------+-------------+---------------+--------------+---
----+---------------+----------------+----------------+-----------------+---------------+------------
204877 | 16384 | replicator | standby1 | | | | | 3310 |
| | | | | |
(1 row)
除了普通用户digoal, 还有几个用户是RDS后台用的，复制用的。
postgres=> \du
List of roles
Role name | Attributes | Member of
-------------------------+------------------------------------------------+-----------
aurora | Superuser | {}
aurora_proxy | Superuser | {}
digoal | Create role, Create DB | {}
pgrdskp501t1znuuzp2xxxx | Superuser, Create role, Create DB, Replication | {} -- 这里可能暴露了主机名，建议改改
replicator | Superuser, Replication | {}
待续。。。
后期再测试使用plproxy分布式处理的性能
【参考】
http://blog.163.com/digoal@126/blog/static/163877040201542103933969/
http://blog.163.com/digoal@126/blog/static/1638770402015463252387/
http://blog.163.com/digoal@126/blog/static/16387704020154651655783/
http://blog.163.com/digoal@126/blog/static/16387704020154653422892/
http://blog.163.com/digoal@126/blog/static/16387704020154811421484/
http://blog.163.com/digoal@126/blog/static/16387704020154129958753/
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