2\u3001\u51b7\u51bb\u8001\u7684Txid <\/p>\n\n\n\n
- \n
- \u5fc5\u8981\u65f6\u51bb\u7ed3\u8001\u5143\u7ec4\u7684Txid <\/li>\n\n\n\n
- \u66f4\u65b0\u51bb\u7ed3\u7684\u4e0e\u7cfb\u7edf\u76ee\u5f55\uff08pg_database\u548cpg_class\uff09\u76f8\u5173\u7684txid <\/li>\n\n\n\n
- \u5982\u6709\u53ef\u80fd\uff0c\u79fb\u9664clog\u4e2d\u4e0d\u5fc5\u8981\u7684\u90e8\u5206<\/li>\n<\/ul>\n\n\n\n
3\u3001\u5176\u4ed6 <\/p>\n\n\n\n
- \n
- \u66f4\u65b0\u5df2\u5904\u7406\u8868\u7684FSM\u548cVM\u3002 <\/li>\n\n\n\n
- \u66f4\u65b0\u51e0\u4e2a\u7edf\u8ba1\u6570\u636e\uff08pg_stat_all_tables\u7b49\uff09\u3002<\/li>\n<\/ul>\n\n\n\n
2 \u5206\u7c7b<\/h1>\n\n\n\n
2.1 \u666e\u901avacuum<\/h2>\n\n\n\n
\uff081\uff09 \u4ece\u6307\u5b9a\u7684\u8868\u4e2d\u83b7\u53d6\u6bcf\u4e2a\u8868\u3002 <\/p>\n\n\n\n
\uff082\uff09 \u83b7\u53d6\u8868\u7684ShareUpdateExclusiveLock\u9501\u3002\u6b64\u9501\u5141\u8bb8\u8bfb\u53d6\u5176\u4ed6\u4e8b\u52a1\u3002 <\/p>\n\n\n\n
\uff083\uff09 \u626b\u63cf\u6240\u6709\u9875\u9762\u4ee5\u83b7\u53d6\u6240\u6709\u6b7b\u5143\u7ec4\uff0c\u5fc5\u8981\u65f6\u51bb\u7ed3\u65e7\u5143\u7ec4\u3002 <\/p>\n\n\n\n
\uff084\uff09 \u5982\u679c\u5b58\u5728\uff0c\u5219\u79fb\u9664\u6307\u5411\u76f8\u5e94\u6b7b\u5143\u7ec4\u7684\u7d22\u5f15\u5143\u7ec4\u3002 <\/p>\n\n\n\n
\uff085\uff09 \u5bf9\u8868\u7684\u6bcf\u4e00\u9875\u6267\u884c\u4ee5\u4e0b\u6b65\u9aa4\uff086\uff09\u548c\uff087\uff09\u3002 <\/p>\n\n\n\n
\uff086\uff09 \u79fb\u9664\u6b7b\u5143\u7ec4\u5e76\u91cd\u65b0\u5206\u914d\u9875\u9762\u4e2d\u7684\u6d3b\u5143\u7ec4\u3002 <\/p>\n\n\n\n
\uff087\uff09 \u66f4\u65b0\u76ee\u6807\u8868\u7684\u76f8\u5e94FSM\u548cVM\u3002 <\/p>\n\n\n\n
\uff088\uff09 \u5982\u679c\u6700\u540e\u4e00\u9875\u6ca1\u6709\u5143\u7ec4\uff0c\u5219\u622a\u65ad\u6700\u540e\u4e00\u9875\u3002 <\/p>\n\n\n\n
\uff089\uff09 \u66f4\u65b0\u4e0e\u76ee\u6807\u8868\u7684\u771f\u7a7a\u5904\u7406\u76f8\u5173\u7684\u7edf\u8ba1\u4fe1\u606f\u548c\u7cfb\u7edf\u76ee\u5f55\u3002 <\/p>\n\n\n\n
\uff0810\uff09 \u66f4\u65b0\u4e0e\u771f\u7a7a\u5904\u7406\u76f8\u5173\u7684\u7edf\u8ba1\u6570\u636e\u548c\u7cfb\u7edf\u76ee\u5f55\u3002 <\/p>\n\n\n\n
\uff0811\uff09 \u5982\u679c\u53ef\u80fd\u7684\u8bdd\uff0c\u5220\u9664\u4e0d\u5fc5\u8981\u7684\u6587\u4ef6\u548cclog\u7684\u9875\u9762<\/p>\n\n\n\n
![\"\"](\"https:\/\/yuzikimikage.top\/wp-content\/uploads\/2025\/11\/1764233736-image.jpg\")
<\/figure>\n\n\n\n\u6e05\u7406\u8fc7\u7a0b\u4f1a\u53c2\u8003vm\u6587\u4ef6\u8fdb\u884c\u53ef\u89c1\u6027\u5224\u65ad\uff0c\u8df3\u8fc7\u4e0d\u5305\u542b\u6b7b\u5143\u7ec4\u7684\u9875\uff0c\u4ece\u800c\u52a0\u901f\u6e05\u7406\u8fc7\u7a0b\u3002<\/p>\n\n\n\n
- \n
- VM\u57289.6\u7248\u4e2d\u5f97\u5230\u4e86\u589e\u5f3a\uff0c\u4ee5\u63d0\u9ad8\u51bb\u7ed3\u5904\u7406\u7684\u6548\u7387<\/li>\n\n\n\n
- \u65b0\u7684VM\u663e\u793a\u9875\u9762\u53ef\u89c1\u6027\u548c\u5173\u4e8e\u5728\u6bcf\u4e2a\u9875\u9762\u4e2d\u5143\u7ec4\u662f\u5426\u51bb\u7ed3\u7684\u4fe1\u606f<\/li>\n<\/ul>\n\n\n\n
![\"\"](\"https:\/\/yuzikimikage.top\/wp-content\/uploads\/2025\/11\/1764233736-image-1.jpg\")
<\/figure>\n\n\n\n2.2 \u6df1\u5ea6vacuum<\/h2>\n\n\n\n
![\"\"](\"https:\/\/yuzikimikage.top\/wp-content\/uploads\/2025\/11\/1764233736-image-2.jpg\")
<\/figure>\n\n\n\nVacuum full\uff1a\u521b\u5efa\u4e86\u65b0\u7684\u6570\u636e\u6587\u4ef6\uff0c\u56e0\u6b64relfilenode \u4f1a\u6539\u53d8\uff0c\u671f\u95f4\u4f1a\u963b\u585e\u8868\u4e0a\u7684\u4e00\u5207\u8bbf\u95ee\u3002<\/p>\n\n\n\n
3 \u51bb\u7ed3\u8fc7\u7a0b<\/h1>\n\n\n\n
\u51bb\u7ed3\u6781\u9650txid\nfreezeLimit_txid=(OldestXmin\u2212vacuum_freeze_min_age)<\/code><\/pre>\n\n\n\n\u542f\u52a8\u51bb\u7ed3\u5904\u7406\u65f6\uff0cPostgreSQL\u8ba1\u7b97\u51bb\u7ed3\u9650\u5236txid\uff0c\u5e76\u51bb\u7ed3t_xmin\u5c0f\u4e8e\u51bb\u7ed3\u9650\u5236txid\u7684\u5143\u7ec4\u3002<\/p>\n\n\n\n
\u5176\u4e2d\u201cOldestXmin\u201d\u662f\u5f53\u524d\u8fd0\u884c\u7684\u4e8b\u52a1\u4e2d\u6700\u65e9\u7684txid\u3002\u4f8b\u5982\uff0c\u5982\u679c\u5728\u6267\u884cVACUUM\u547d\u4ee4\u65f6\u6709\u4e09\u4e2a\u4e8b\u52a1\uff08txids 100\u3001101\u548c102\uff09\u6b63\u5728\u8fd0\u884c\uff0c\u201cOldestXmin\u201d\u662f100\u3002\u5982\u679c\u5f53\u524d\u6ca1\u6709\u5176\u5b83\u4e8b\u52a1\uff0c \u201cOldestXmin\u201d\u662f\u6267\u884c\u6b64\u771f\u7a7a\u547d\u4ee4\u7684txid\u3002\u8fd9\u91cc\uff0cvacuum_freeze_min_age\u662f\u4e00\u4e2a\u914d\u7f6e\u53c2\u6570\uff08\u9ed8\u8ba4\u503c50000000\uff09<\/p>\n\n\n\n
\u6a21\u5f0f<\/strong><\/td> \u89e6\u53d1\u65f6\u673a<\/strong><\/td><\/tr><\/thead> lazy<\/strong><\/td> \u666e\u901a VACUUM\uff08\u81ea\u52a8\u6216\u624b\u52a8\uff09
\u53ea\u8981 \u8868\u7684 relfrozenxid <\/strong>\u8fd8\u6ca1\u8d85\u8fc7 vacuum_freeze_table_age<\/strong><\/td><\/tr>eager<\/strong><\/td> \u5f53 \u8868\u7684 relfrozenxid \u2265 vacuum_freeze_table_age<\/strong>
\u6216 \u624b\u52a8 VACUUM FREEZE<\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nvacuum_freeze_table_age \u9ed8\u8ba4 150 000 000\uff081.5 \u4ebf\u4e8b\u52a1\uff09<\/p>\n\n\n\n
3.1 \u61d2\u60f0\u6a21\u5f0f\uff08Lazy Mode\uff09<\/h2>\n\n\n\n
\u51bb\u7ed3\u8fc7\u7a0b\u4f1a\u6807\u8bb0\u5143\u7ec4\u7684t_infomask \u6807\u5fd7\u4f4d<\/p>\n\n\n\n
![\"\"](\"https:\/\/yuzikimikage.top\/wp-content\/uploads\/2025\/11\/1764233736-image-3.jpg\")
<\/figure>\n\n\n\n\u61d2\u60f0\u6a21\u5f0f\u4f1a\u6839\u636eVM\u6587\u4ef6\u8df3\u8fc7 \u4e0d\u5305\u542b\u6b7b\u5143\u7ec4\u7684\u9875<\/p>\n\n\n\n
3.2 \u6025\u5207\u6a21\u5f0f\uff08Eager Mode\uff09<\/h2>\n\n\n\n
\u6ee1\u8db3\u4ee5\u4e0b\u6761\u4ef6\u65f6\uff0c\u542f\u52a8\u6025\u5207\u6a21\u5f0f\npg_database.datfrozenxid<(OldestXmin\u2212vacuum_freeze_table_age)<\/code><\/pre>\n\n\n\n\u6025\u5207\u6a21\u5f0f\u5f25\u8865\u4e86\u61d2\u60f0\u6a21\u5f0f\u7684\u7f3a\u9677\u3002\u5b83\u6839\u636eVM\u6587\u4ef6\u8fdb\u884c\u5224\u65ad\uff0c\u6240\u6709\u5143\u7ec4\u90fd\u5df2\u51bb\u7ed3\u7684\u9875\u9762\u4f1a\u88ab\u8df3\u8fc7\uff0c\u66f4\u65b0\u76f8\u5173\u7684\u7cfb\u7edf\u76ee\u5f55\uff0c\u5e76\u5728\u53ef\u80fd\u7684\u60c5\u51b5\u4e0b\u5220\u9664\u4e0d\u5fc5\u8981\u7684\u6587\u4ef6\u548cclog\u9875\u9762\u3002<\/p>\n\n\n\n
Clog\u6587\u4ef6\u8bb0\u5f55\u4e86\u4e8b\u52a1\u7684\u72b6\u6001\uff0c\u53ef\u7528\u4e8e\u5143\u7ec4\u7684\u53ef\u89c1\u6027\u5224\u65ad\u3002\u5df2\u88ab\u51bb\u7ed3\u7684\u5143\u7ec4\u90fd\u662f\u53ef\u89c1\u7684\uff0c\u56e0\u6b64\u5c31\u4e0d\u9700\u8981\u4fdd\u7559\u76f8\u5e94\u7684clog\u6587\u4ef6\u3002<\/p>\n\n\n\n
4 Autovacuum<\/h1>\n\n\n\n
\u81ea\u52a8\u6e05\u7406\u8fc7\u7a0b\uff0c\u9700\u8981\u6253\u5f00\u53c2\u6570<\/p>\n\n\n\n
autovacuum = on # ( ON by default )\ntrack_counts = on # ( ON by default )<\/code><\/pre>\n\n\n\n4.1 \u89e6\u53d1\u6761\u4ef6<\/h2>\n\n\n\n
Autovacuum\u64cd\u4f5c\u7684\u5b9e\u9645\u5185\u5bb9:<\/p>\n\n\n\n
1)vacuum;<\/p>\n\n\n\n
2)Analyze<\/p>\n\n\n\n
Autovacuum vacuum\u89e6\u53d1\u6761\u4ef6\uff08\u5982\u679c\u7531\u4e8e\u66f4\u65b0\u548c\u5220\u9664\uff0c\u8868\u4e2d\u7684\u5b9e\u9645\u6b7b\u5143\u7ec4\u6570\u8d85\u8fc7\u6b64\u6709\u6548\u9608\u503c\uff0c\u5219\u8be5\u8868\u5c06\u6210\u4e3aautovacuum\u7684\u5019\u9009\u8868\uff09\uff1a<\/p>\n\n\n\n
Autovacuum VACUUM thresold for a table = autovacuum_vacuum_scale_factor * number of tuples + autovacuum_vacuum_threshold<\/code><\/pre>\n\n\n\nAutovacuum ANALYZE\u89e6\u53d1\u6761\u4ef6\uff08\u81ea\u4e0a\u6b21\u5206\u6790\u4ee5\u6765\u63d2\u5165\/\u5220\u9664\/\u66f4\u65b0\u603b\u6570\u8d85\u8fc7\u6b64\u9608\u503c\u7684\u4efb\u4f55\u8868\u90fd\u6709\u8d44\u683c\u8fdb\u884cautovacuum\u5206\u6790\uff09<\/p>\n\n\n\n
Autovacuum ANALYZE threshold for a table = autovacuum_analyze_scale_factor * number of tuples + autovacuum_analyze_threshold<\/code><\/pre>\n\n\n\n<\/p>\n\n\n\n
4.2 \u76f8\u5173\u53c2\u6570<\/h2>\n\n\n\n
\u53c2\u6570\u540d <\/td> \u5355\u4f4d\/\u9ed8\u8ba4 <\/td> \u4e00\u53e5\u8bdd\u4f5c\u7528 <\/td> \u8c03\u4f18\u63d0\u793a <\/td><\/tr> autovacuum <\/td> bool\/on <\/td> \u603b\u5f00\u5173\uff1boff=\u5b8c\u5168\u7981\u7528\u540e\u53f0\u81ea\u52a8\u6e05\u7406 <\/td> \u751f\u4ea7\u5fc5\u987b on\uff0c\u53ea\u4e34\u65f6\u6392\u969c\u53ef\u5173 <\/td><\/tr> autovacuum_max_workers <\/td> int\/3 \u2605 <\/td> \u00a0\u63a7\u5236\u81ea\u52a8\u6e05\u7406\uff08autovacuum\uff09\u8fdb\u7a0b\u7684\u6700\u5927\u5e76\u53d1\u6570\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/td> CPU\u22658 \u6838\u53ef\u21926\uff1bIO \u5403\u7d27\u65f6\u5148\u63d0 worker \u518d\u964d cost <\/td><\/tr> autovacuum_naptime <\/td> s\/60 \u2605 <\/td> \u00a0\u4e24\u6b21\u6e05\u7406\u64cd\u4f5c\u4e4b\u95f4\u7684\u7b49\u5f85\u65f6\u95f4\u00a0,\u63a7\u5236 autovacuum \u7684\u8fd0\u884c\u9891\u7387\u3002\u8f83\u77ed\u7684\u65f6\u95f4\u95f4\u9694\u610f\u5473\u7740 autovacuum \u66f4\u9891\u7e41\u5730\u8fd0\u884c\u3002\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/td> \u5927\u5e93\u53ef\u628a 60\u219230 \u8ba9\u201c\u5927\u8868\u201d\u66f4\u5feb\u88ab\u626b\u63cf\u5230 <\/td><\/tr> autovacuum_vacuum_threshold <\/td> int\/50 \u2605 <\/td> \u89e6\u53d1 VACUUM \u57fa\u7840\u884c\u6570\uff1adeadtuple \u2265 50 + 0.2\u00d7reltuples<\/td> \u5927\u8868\u21920\uff0c\u9760\u6bd4\u4f8b\u5373\u53ef <\/td><\/tr> autovacuum_vacuum_scale_factor <\/td> float\/0.2 \u2605 <\/td> \u00a0\u4e0e\u4e0a\u884c\u7ec4\u6210\u201c20% \u53d8\u5316\u5c31\u626b\u201d\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/td> 10 TB \u7ea7\u8868\u21920.05 \u751a\u81f3 0.01\uff0c\u51cf\u5c11\u81a8\u80c0 <\/td><\/tr> autovacuum_analyze_threshold <\/td> int\/50 <\/td> \u89e6\u53d1 ANALYZE \u57fa\u7840\u884c\u6570 <\/td> \u540c threshold\uff0c\u901a\u5e38\u540c\u6b65\u8c03 <\/td><\/tr> autovacuum_analyze_scale_factor <\/td> float\/0.1 <\/td> 10% \u53d8\u5316\u5c31 ANALYZE <\/td> \u53ef\u7565\u4f4e\u4e8e vacuum_factor <\/td><\/tr> autovacuum_vacuum_cost_limit <\/td> int\/-1 <\/td> \u672c\u8868 cost \u4e0a\u9650\uff1b-1=\u53d6 vacuum_cost_limit <\/td> IO \u6162\u76d8\u2192\u63d0\u9ad8 200\u21921000 <\/td><\/tr> autovacuum_vacuum_cost_delay <\/td> ms\/-1 <\/td> \u00a0autovacuum \u6bcf\u6b21\u6e05\u7406\u64cd\u4f5c\u4e4b\u95f4\u7684\u5ef6\u8fdf\u65f6\u95f4\u3002\u5b83\u7528\u4e8e\u63a7\u5236 autovacuum \u7684\u8d44\u6e90\u6d88\u8017\uff0c\u907f\u514d\u5bf9\u751f\u4ea7\u73af\u5883\u9020\u6210\u8fc7\u5927\u538b\u529b\u3002
\u8f83\u4f4e\u7684\u503c\u610f\u5473\u7740 autovacuum \u5728\u6e05\u7406\u65f6\u4f1a\u66f4\u79ef\u6781\u5730\u8fd0\u884c\uff0c\u4f46\u53ef\u80fd\u4f1a\u5bf9\u7cfb\u7edf\u6027\u80fd\u4ea7\u751f\u66f4\u5927\u5f71\u54cd\u3002\uff1b-1=\u53d6 vacuum_cost_delay\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/td>\u4e0e cost_limit \u53cd\u6bd4\uff0c\u53ef\u8c03 0 \u52a0\u901f <\/td><\/tr> autovacuum_freeze_max_age <\/td> xid\/200 000 000 \u2605<\/td> \u8868 relfrozenxid \u8ddd\u5f53\u524d XID \u8d85\u6b64\u503c\u2192\u5f3a\u5236 freeze <\/td> \u63d0\u524d\u2192150 000 000 \u51cf\u5c11 eager VACUUM <\/td><\/tr> autovacuum_multixact_freeze_max_age <\/td> xid\/400 000 000 <\/td> MultiXact \u7248\u540c\u4e0a <\/td> \u901a\u5e38\u540c\u6bd4\u4f8b\u4e0b\u8c03 <\/td><\/tr> autovacuum_vacuum_insert_threshold <\/td> int\/1000 <\/td> \u226517 \u65b0\u589e\uff1aINSERT \u884c\u6570\u57fa\u7840\u503c <\/td> _append-only \u8868\u21920 \u9760\u56e0\u5b50 <\/td><\/tr> autovacuum_vacuum_insert_scale_factor<\/td> float\/0.2 <\/td> INSERT 20% \u4e5f vacuum <\/td> append-only\u21920.05 \u9632\u65b0\u9875\u81a8\u80c0 <\/td><\/tr> log_autovacuum_min_duration <\/td> ms\/-1 \u2605 <\/td> \u2265\u6b64\u6beb\u79d2\u2192\u65e5\u5fd7\uff1b-1=\u4e0d\u8bb0\uff0c0=\u5168\u8bb0 <\/td> \u6392\u969c\u65f6\u21920\uff0c\u65e5\u5e38\u2192250 ms <\/td><\/tr> vacuum_cost_limit <\/td> int\/200 <\/td> \u00a0\u63a7\u5236 VACUUM \u64cd\u4f5c\uff08\u6e05\u7406\u548c\u56de\u6536\u7a7a\u95f4\uff09\u7684\u8d44\u6e90\u6d88\u8017\u9650\u5236\u3002\u5b83\u5b9a\u4e49\u4e86\u5728\u6bcf\u6b21 VACUUM \u64cd\u4f5c\u4e2d\uff0c\u5141\u8bb8\u6d88\u8017\u7684\u6700\u5927\u201c\u6210\u672c\u201d\uff08\u4ee5\u5355\u4f4d\u8ba1\uff09\u3002\u6210\u672c\u662f\u6839\u636e I\/O \u548c CPU \u6d88\u8017\u8ba1\u7b97\u7684\u3002
\u8f83\u9ad8\u7684\u503c\u5141\u8bb8 VACUUM \u64cd\u4f5c\u66f4\u79ef\u6781\u5730\u4f7f\u7528\u8d44\u6e90\uff0c\u800c\u8f83\u4f4e\u7684\u503c\u5219\u9650\u5236\u5176\u8d44\u6e90\u4f7f\u7528\uff0c\u4ee5\u51cf\u5c11\u5bf9\u751f\u4ea7\u73af\u5883\u7684\u5f71\u54cd\u3002\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/td>\u4e0e autovacuum_vacuum_cost_limit \u8054\u52a8<\/td><\/tr> vacuum_cost_delay <\/td> ms\/0 <\/td> \u00a0vacuum \u6bcf\u6b21\u6e05\u7406\u64cd\u4f5c\u4e4b\u95f4\u7684\u5ef6\u8fdf\u65f6\u95f4<\/td> IO \u5403\u7d27\u21922-10 ms\uff0cSSD\u21920 <\/td><\/tr> vacuum_freeze_min_age <\/td> xid\/50 000 000 <\/td> \u9875\u7ea7 freeze \u6700\u5c0f XID \u5e74\u9f84 <\/td> \u901a\u5e38\u4e0d\u52a8\uff1b\u8c03\u5927\u2192\u5c11\u5199\uff0c\u8c03\u5c0f\u2192\u65e9 freeze <\/td><\/tr> vacuum_freeze_table_age <\/td> xid\/150 000 000 \u2605<\/td> \u8868\u7ea7 eager freeze \u9608\u503c <\/td> \u4e0e freeze_max_age \u540c\u6b65\u4e0b\u8c03 <\/td><\/tr> vacuum_multixact_freeze_table_age <\/td> xid\/150 000 000 <\/td> MultiXact \u7248\u540c\u4e0a <\/td> \u540c\u4e0a <\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n \u4f7f\u7528\u53e3\u8bc0
\u201cworker+naptime<\/strong> \u51b3\u5b9a\u626b\u591a\u5feb\uff1bfactor+threshold<\/strong> \u51b3\u5b9a\u626b\u4e0d\u626b\uff1bcost+delay<\/strong> \u51b3\u5b9a\u626b\u591a\u731b\uff1bfreeze_max_age<\/strong> \u51b3\u5b9a\u626b\u591a\u72e0\uff1blog_duration<\/strong> \u770b\u626b\u591a\u6162\u3002\u201d<\/p>\n\n\n\n5 \u76f8\u5173\u67e5\u8be2\u811a\u672c<\/h1>\n\n\n\n
<\/p>\n\n\n\n
#\u67e5\u8be2pg_class.relfrozenxid\u548cpg_database.datfrozenxid\nSELECT n.nspname as \"Schema\", c.relname as \"Name\", c.relfrozenxid\n FROM pg_catalog.pg_class c\n LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace\n WHERE c.relkind IN ('r','')\n AND n.nspname <> 'information_schema' AND n.nspname !~ '^pg_toast'\n AND pg_catalog.pg_table_is_visible(c.oid)\n ORDER BY c.relfrozenxid::text::bigint DESC;\n\n\nSELECT datname, datfrozenxid FROM pg_database WHERE datname = 'testdb';\n\n#\u67e5\u8be2\u67d0\u5f20\u8868\u7684\u7a7a\u95f2\u7a7a\u95f4\u6bd4\u4f8b\ntestdb=# CREATE EXTENSION pg_freespacemap;\nCREATE EXTENSION\ntestdb=# SELECT count(*) as \"number of pages\",\n pg_size_pretty(cast(avg(avail) as bigint)) as \"Av. freespace size\",\n round(100 * avg(avail)\/8192 ,2) as \"Av. freespace ratio\"\n FROM pg_freespace('accounts');\n\n#\u67e5\u8be2\u68c0\u67e5\u6307\u5b9a\u8868\u7684\u6bcf\u9875\u7684\u53ef\u7528\u7a7a\u95f4\u6bd4\u7387\nSELECT *, round(100 * avail\/8192 ,2) as \"freespace ratio\"\n FROM pg_freespace('accounts');\n\n#\u67e5\u8be2\u8868\u4e0a\u7684\u63d2\u5165\/\u5220\u9664\/\u66f4\u65b0\u6570\nSELECT n_tup_ins as \"inserts\",n_tup_upd as \"updates\",n_tup_del as \"deletes\", n_live_tup as \"live_tuples\", n_dead_tup as \"dead_tuples\"\n\t FROM pg_stat_user_tables\n\t WHERE schemaname = 'scott' and relname = 'employee';\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"1 \u4f5c\u7528 1\u3001\u79fb\u9664\u6b7b\u5143\u7ec4   …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"emotion":"","emotion_color":"","title_style":"","license":"","footnotes":""},"categories":[22],"tags":[],"class_list":["post-314","post","type-post","status-publish","format-standard","hentry","category-22"],"_links":{"self":[{"href":"https:\/\/yuzikimikage.top\/index.php\/wp-json\/wp\/v2\/posts\/314","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/yuzikimikage.top\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/yuzikimikage.top\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/yuzikimikage.top\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/yuzikimikage.top\/index.php\/wp-json\/wp\/v2\/comments?post=314"}],"version-history":[{"count":5,"href":"https:\/\/yuzikimikage.top\/index.php\/wp-json\/wp\/v2\/posts\/314\/revisions"}],"predecessor-version":[{"id":325,"href":"https:\/\/yuzikimikage.top\/index.php\/wp-json\/wp\/v2\/posts\/314\/revisions\/325"}],"wp:attachment":[{"href":"https:\/\/yuzikimikage.top\/index.php\/wp-json\/wp\/v2\/media?parent=314"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/yuzikimikage.top\/index.php\/wp-json\/wp\/v2\/categories?post=314"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/yuzikimikage.top\/index.php\/wp-json\/wp\/v2\/tags?post=314"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}