查看是否存在无效索引

SELECT * FROM pg_class, pg_index WHERE pg_index.indisvalid = false AND pg_index.indexrelid = pg_class.oid;

查看大小

查看表大小:

\d+

查看数据库大小:

\l+

查看表，索引及总大小

SELECT
    table_name,
    pg_size_pretty(table_size) AS table_size,
    pg_size_pretty(indexes_size) AS indexes_size,
    pg_size_pretty(total_size) AS total_size
FROM (
    SELECT
        table_name,
        pg_table_size(table_name) AS table_size,
        pg_indexes_size(table_name) AS indexes_size,
        pg_total_relation_size(table_name) AS total_size
    FROM (
        SELECT ('"' || table_schema || '"."' || table_name || '"') AS table_name
        FROM information_schema.tables
    ) AS all_tables
    ORDER BY total_size DESC
) AS pretty_sizes;

表访问统计

select schemaname,relname,seq_scan,idx_scan,cast(idx_scan as numeric) / (idx_scan + seq_scan)
 as idx_scan_pct 
 from pg_stat_user_tables where (idx_scan +seq_scan) >0 order by idx_scan_pct;

表I/O统计

select relname,cast(heap_blks_hit as numeric) /(heap_blks_hit +heap_blks_read) 
 as hit_pct,heap_blks_hit,heap_blks_read from pg_statio_user_tables 
  where (heap_blks_hit + heap_blks_read) >0 order by hit_pct;

索引访问统计

select relname,cast(idx_blks_hit as numeric) /(idx_blks_hit + idx_blks_read )
  as hit_pct,idx_blks_hit,idx_blks_read from pg_statio_user_tables 
  where (idx_blks_hit +idx_blks_read) >0 order by hit_pct;

索引I/O统计

select indexrelname,cast(idx_blks_hit as numeric) /( idx_blks_hit + idx_blks_read) 
 as hit_pct,idx_blks_hit,idx_blks_read from pg_statio_user_indexes 
 where (idx_blks_hit +idx_blks_read)>0 order by hit_pct ;

按索引访问次统计

select schemaname,relname,indexrelname,idx_scan,pg_size_pretty(pg_relation_size(i.indexrelid)) 
 as index_size from pg_stat_user_indexes i join pg_index using (indexrelid)
 where indisunique is false order by idx_scan,relname;

获取用户所属的schema

\dn+

常用 SQL 收集

insert on conflict

INSERT INTO tbl_Employee 
VALUES (7,'Ramu')
ON CONFLICT (EmpID)
DO UPDATE SET EmpName = Excluded.EmpName;

-- 什么也不做
ON CONFLICT (EmpID) DO NOTHING;

索引相关操作

create [unique] index [CONCURRENTLY] [索引名, 如果不指定, 则由 pg 自动创建相应的名] on 表名 (列名 1, 列名 2);

drop index 索引名 [CASCADE];

copy

-- tsv 格式
copy hs300_pe from '/tmp/hs300.csv' DELIMITER E',';

-- csv 格式
copy hs300_pb from '/tmp/hs300.pb.csv' csv

备份/还原

pg_dump --host localhost --port 5432 --username postgres --format plain --ignore-version --verbose --file "<abstract_file_path>" --table public.tablename dbname


psql -U username -d database -1 -f your_dump.sql

免提示输入密码

PGPASSWORD=你的密码 psql -U postgres -c "select * from t limit 10;"