Table of Contents
表与索引膨胀 TOP 10
库表统计信息长时间未更新 TOP 10
库表年龄 TOP 10
巡检处理脚本
定时任务策略
1、表与索引膨胀 TOP 10
CREATE SCHEMA IF NOT EXISTS monitor;
create OR REPLACE view monitor.pg_stat_bloat_tables as
-- 查看表膨胀
with tmp as (
SELECT current_database(), schemaname, tblname, bs*tblpages AS real_size,
(tblpages-est_tblpages)*bs AS extra_size,
CASE WHEN tblpages > 0 AND tblpages - est_tblpages > 0
THEN 100 * (tblpages - est_tblpages)/tblpages::float
ELSE 0
END AS extra_pct, fillfactor,
CASE WHEN tblpages - est_tblpages_ff > 0
THEN (tblpages-est_tblpages_ff)*bs
ELSE 0
END AS bloat_size,
CASE WHEN tblpages > 0 AND tblpages - est_tblpages_ff > 0
THEN 100 * (tblpages - est_tblpages_ff)/tblpages::float
ELSE 0
END AS bloat_pct, is_na
-- , tpl_hdr_size, tpl_data_size, (pst).free_percent + (pst).dead_tuple_percent AS real_frag -- (DEBUG INFO)
FROM (
SELECT ceil( reltuples / ( (bs-page_hdr)/tpl_size ) ) + ceil( toasttuples / 4 ) AS est_tblpages,
ceil( reltuples / ( (bs-page_hdr)*fillfactor/(tpl_size*100) ) ) + ceil( toasttuples / 4 ) AS est_tblpages_ff,
tblpages, fillfactor, bs, tblid, schemaname, tblname, heappages, toastpages, is_na
-- , tpl_hdr_size, tpl_data_size, pgstattuple(tblid) AS pst -- (DEBUG INFO)
FROM (
SELECT
( 4 + tpl_hdr_size + tpl_data_size + (2*ma)
- CASE WHEN tpl_hdr_size%ma = 0 THEN ma ELSE tpl_hdr_size%ma END
- CASE WHEN ceil(tpl_data_size)::int%ma = 0 THEN ma ELSE ceil(tpl_data_size)::int%ma END
) AS tpl_size, bs - page_hdr AS size_per_block, (heappages + toastpages) AS tblpages, heappages,
toastpages, reltuples, toasttuples, bs, page_hdr, tblid, schemaname, tblname, fillfactor, is_na
-- , tpl_hdr_size, tpl_data_size
FROM (
SELECT
tbl.oid AS tblid, ns.nspname AS schemaname, tbl.relname AS tblname, tbl.reltuples,
tbl.relpages AS heappages, coalesce(toast.relpages, 0) AS toastpages,
coalesce(toast.reltuples, 0) AS toasttuples,
coalesce(substring(
array_to_string(tbl.reloptions, ' ')
FROM 'fillfactor=([0-9]+)')::smallint, 100) AS fillfactor,
current_setting('block_size')::numeric AS bs,
CASE WHEN version()~'mingw32' OR version()~'64-bit|x86_64|ppc64|ia64|amd64' THEN 8 ELSE 4 END AS ma,
24 AS page_hdr,
23 + CASE WHEN MAX(coalesce(s.null_frac,0)) > 0 THEN ( 7 + count(s.attname) ) / 8 ELSE 0::int END
+ CASE WHEN bool_or(att.attname = 'oid' and att.attnum < 0) THEN 4 ELSE 0 END AS tpl_hdr_size,
sum( (1-coalesce(s.null_frac, 0)) * coalesce(s.avg_width, 0) ) AS tpl_data_size,
bool_or(att.atttypid = 'pg_catalog.name'::regtype)
OR sum(CASE WHEN att.attnum > 0 THEN 1 ELSE 0 END) <> count(s.attname) AS is_na
FROM pg_attribute AS att
JOIN pg_class AS tbl ON att.attrelid = tbl.oid
JOIN pg_namespace AS ns ON ns.oid = tbl.relnamespace
LEFT JOIN pg_stats AS s ON s.schemaname=ns.nspname
AND s.tablename = tbl.relname AND s.inherited=false AND s.attname=att.attname
LEFT JOIN pg_class AS toast ON tbl.reltoastrelid = toast.oid
WHERE NOT att.attisdropped
AND tbl.relkind in ('r','m','p')
GROUP BY 1,2,3,4,5,6,7,8,9,10
ORDER BY 2,3
) AS s
) AS s2
) AS s3
)
-- WHERE NOT is_na
-- AND tblpages*((pst).free_percent + (pst).dead_tuple_percent)::float4/100 >= 1
select * from tmp where schemaname='public';
create view monitor.pg_stat_bloat_index_tables as
with tmp as (
SELECT current_database(), nspname AS schemaname, tblname, idxname, bs*(relpages)::bigint AS real_size,
bs*(relpages-est_pages)::bigint AS extra_size,
100 * (relpages-est_pages)::float / relpages AS extra_pct,
fillfactor,
CASE WHEN relpages > est_pages_ff
THEN bs*(relpages-est_pages_ff)
ELSE 0
END AS bloat_size,
100 * (relpages-est_pages_ff)::float / relpages AS bloat_pct,
is_na
-- , 100-(pst).avg_leaf_density AS pst_avg_bloat, est_pages, index_tuple_hdr_bm, maxalign, pagehdr, nulldatawidth, nulldatahdrwidth, reltuples, relpages -- (DEBUG INFO)
FROM (
SELECT coalesce(1 +
ceil(reltuples/floor((bs-pageopqdata-pagehdr)/(4+nulldatahdrwidth)::float)), 0 -- ItemIdData size + computed avg size of a tuple (nulldatahdrwidth)
) AS est_pages,
coalesce(1 +
ceil(reltuples/floor((bs-pageopqdata-pagehdr)*fillfactor/(100*(4+nulldatahdrwidth)::float))), 0
) AS est_pages_ff,
bs, nspname, tblname, idxname, relpages, fillfactor, is_na
-- , pgstatindex(idxoid) AS pst, index_tuple_hdr_bm, maxalign, pagehdr, nulldatawidth, nulldatahdrwidth, reltuples -- (DEBUG INFO)
FROM (
SELECT maxalign, bs, nspname, tblname, idxname, reltuples, relpages, idxoid, fillfactor,
( index_tuple_hdr_bm +
maxalign - CASE -- Add padding to the index tuple header to align on MAXALIGN
WHEN index_tuple_hdr_bm%maxalign = 0 THEN maxalign
ELSE index_tuple_hdr_bm%maxalign
END
+ nulldatawidth + maxalign - CASE -- Add padding to the data to align on MAXALIGN
WHEN nulldatawidth = 0 THEN 0
WHEN nulldatawidth::integer%maxalign = 0 THEN maxalign
ELSE nulldatawidth::integer%maxalign
END
)::numeric AS nulldatahdrwidth, pagehdr, pageopqdata, is_na
-- , index_tuple_hdr_bm, nulldatawidth -- (DEBUG INFO)
FROM (
SELECT n.nspname, ct.relname AS tblname, i.idxname, i.reltuples, i.relpages,
i.idxoid, i.fillfactor, current_setting('block_size')::numeric AS bs,
CASE -- MAXALIGN: 4 on 32bits, 8 on 64bits (and mingw32 ?)
WHEN version() ~ 'mingw32' OR version() ~ '64-bit|x86_64|ppc64|ia64|amd64' THEN 8
ELSE 4
END AS maxalign,
/* per page header, fixed size: 20 for 7.X, 24 for others */
24 AS pagehdr,
/* per page btree opaque data */
16 AS pageopqdata,
/* per tuple header: add IndexAttributeBitMapData if some cols are null-able */
CASE WHEN max(coalesce(s.stanullfrac,0)) = 0
THEN 8 -- IndexTupleData size
ELSE 8 + (( 32 + 8 - 1 ) / 8) -- IndexTupleData size + IndexAttributeBitMapData size ( max num filed per index + 8 - 1 /8)
END AS index_tuple_hdr_bm,
/* data len: we remove null values save space using it fractionnal part from stats */
sum( (1-coalesce(s.stanullfrac, 0)) * coalesce(s.stawidth, 1024)) AS nulldatawidth,
max( CASE WHEN a.atttypid = 'pg_catalog.name'::regtype THEN 1 ELSE 0 END ) > 0 AS is_na
FROM (
SELECT idxname, reltuples, relpages, tbloid, idxoid, fillfactor,
CASE WHEN indkey=0 THEN idxoid ELSE tbloid END AS att_rel,
CASE WHEN indkey=0 THEN i ELSE indkey END AS att_pos
FROM (
SELECT idxname, reltuples, relpages, tbloid, idxoid, fillfactor, indkey, generate_series(1,indnatts) AS i
FROM (
SELECT ci.relname AS idxname, ci.reltuples, ci.relpages, i.indrelid AS tbloid,
i.indexrelid AS idxoid,
coalesce(substring(
array_to_string(ci.reloptions, ' ')
from 'fillfactor=([0-9]+)')::smallint, 90) AS fillfactor,
i.indnatts,
string_to_array(textin(int2vectorout(i.indkey)),' ')::int[ ] AS indkey
FROM pg_index i
JOIN pg_class ci ON ci.oid=i.indexrelid
WHERE ci.relam=(SELECT oid FROM pg_am WHERE amname = 'btree')
AND ci.relpages > 0
) AS idx_data
) AS idx_data_cross
) i
JOIN pg_attribute a ON a.attrelid = i.att_rel
AND a.attnum = i.att_pos
JOIN pg_statistic s ON s.starelid = i.att_rel
AND s.staattnum = i.att_pos
JOIN pg_class ct ON ct.oid = i.tbloid
JOIN pg_namespace n ON ct.relnamespace = n.oid
GROUP BY 1,2,3,4,5,6,7,8,9,10
) AS rows_data_stats
) AS rows_hdr_pdg_stats
) AS relation_stats
) select * from tmp where schemaname='public'
ORDER BY bloat_size desc,bloat_pct desc ;
-- 表膨胀 TOP 10 的表, 并且表膨胀大小要超过 10MB, 膨胀率大于 30%
select tblname from monitor.pg_stat_bloat_tables where bloat_size >=1000000 and bloat_pct>=30 order by bloat_size desc , bloat_pct desc limit 10;
-- 索引膨胀 TOP 10 的表, 并且膨胀大小要超过 10MB, 膨胀率大于 30%
with tmp as (select * from monitor.pg_stat_bloat_index_tables where bloat_size >=10000000 and bloat_pct>=30 order by bloat_size desc , bloat_pct desc ) select tblname from tmp group by tblname limit 10;
psql -U postgres -d $db <<"EOF"
(select tblname from monitor.pg_stat_bloat_tables where bloat_size >=1000000 and bloat_pct>=30 order by bloat_size desc , bloat_pct desc limit 10)
union
(with tmp as (select * from monitor.pg_stat_bloat_index_tables where bloat_size >=10000000 and bloat_pct>=30 order by bloat_size desc , bloat_pct desc ) select tblname from tmp group by tblname limit 10)
EOF
2、库表统计信息长时间未更新 TOP 10
-- 查询统计信息最久未更新的前十张表
drop view if exists monitor.pg_stat_nonanalyze_tables;
create or replace view monitor.pg_stat_nonanalyze_tables
as
SELECT
schemaname,
relname AS tablename,
last_analyze,
last_autoanalyze,
-- 计算距离现在的时间差（天数）
EXTRACT(EPOCH FROM (
NOW() - COALESCE(last_analyze, '1970-01-01')
))/86400 AS days_since_last_manual_analyze,
EXTRACT(EPOCH FROM (
NOW() - COALESCE(last_autoanalyze, '1970-01-01')
))/86400 AS days_since_last_auto_analyze,
-- 取两个时间差中的最大值作为排序依据
GREATEST(
NOW() - COALESCE(last_analyze, '1970-01-01'),
NOW() - COALESCE(last_autoanalyze, '1970-01-01')
) AS max_days_since_last_analyze
FROM pg_stat_user_tables
where schemaname='public'
ORDER BY max_days_since_last_analyze DESC
LIMIT 10
;
3、库表年龄 TOP 10
drop view if exists monitor.pg_stat_nonfreeze_tables ;
create or replace view monitor.pg_stat_nonfreeze_tables
as
SELECT
n.nspname AS schemaname,
c.relname AS tablename,
age(c.relfrozenxid) AS xid_age
FROM pg_class c
JOIN pg_namespace n ON n.oid = c.relnamespace
WHERE c.relkind in ('r') -- 普通表
AND n.nspname ='public'
AND age(c.relfrozenxid) > 100000000 -- 超过1亿
ORDER BY age(c.relfrozenxid) DESC
LIMIT 10;
4、巡检处理脚本
# 膨胀清理
psql -Upostgres -d postgres > to_be_repack_tables.txt -qAtX <<"EOF"
-- 表膨胀 TOP 10 的表, 并且表膨胀大小要超过 10MB, 膨胀率大于 30%
(select tblname from monitor.pg_stat_bloat_tables where bloat_size >=1000000 and bloat_pct>=30 order by bloat_size desc , bloat_pct desc limit 10)
union
-- 索引膨胀 TOP 10 的表, 并且膨胀大小要超过 10MB, 膨胀率大于 30%
(with tmp as (select * from monitor.pg_stat_bloat_index_tables where bloat_size >=10000000 and bloat_pct>=30 order by bloat_size desc , bloat_pct desc ) select tblname from tmp group by tblname limit 10)
EOF