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. Pg_dump does not block other database operations. (But it will block the operations that require the exclusive lock, such as vacuum full .) NOTE: If your database structure depends on OID (for example, used as a foreign key), you must tell pg_dump to reverse the oId. To reverse the OID, you can use the-O command line option. It also does not dump "large objects ". If you are using a large object, see the pg_dump command manual page. 2.2 pg_dumpall

The concept of the inert environment is described as follows:1) use an inert environment to replace the normal environment;2) adding neutral substances or additives to objects;3) implementation process in vacuum; The principle of the inert environment is opposite to that of the preceding principle 38. This places the system in an inert environment rather than an active environment. The manufacture of inert environments may consider a variety of envir

. -Z (--analyze) Calculates the statistical value used for the planner. -H (--host=host) Specifies the host name of the PostgreSQL server. -P (--port=port) Specifies the listener port for the server, or the default 5432 if unspecified. -U (--username=username) The login user name for this operation. -W (--no-password) If the current logged-on user does not have a password, you can specify this option to log on direct

avoiding an error when the function contains a forward reference. The target database is Postgres/enterprisedb, and the default value is true. -retrycount VALUE Specifies the number of retries of the MTK migration for objects that failed due to cross schema dependencies. The value parameter should be greater than 0 and the default value is 2. -analyze it will invoke the analyze operation on the target Postgres or Postgres Plus Advanced Server database. ANALYZE collects statistics for migrated t

several values that have special meanings: Txid = 0 means Invalid Txid, usually used as the validity of the judgment Txid;Txid = 1 means Bootstrap Txid, in the present case, only when initializing the database at intidb timeTxid = 2 means Frozen Txid, which is generally used in vacuum (mentioned later). Remember this assumption: TXID Small firms modify tuples that are visible to txid large transactions, and vice versa. 1.2 tuples (t

/python, SQL, and C. Trigger Pre-line triggers, post-line triggers, and statement triggers are supported, and trigger statements are written in a procedural language compound statement. Pre-line triggers, post-line triggers, and statement triggers are supported, and the trigger process is written in C. System configuration File My.conf Postgresql.conf Database configuration My.conf Postgresql.conf Client Connec

compression and MDB database, the SQLite database does not reclaim the control by default, after a large amount of data deletion, the volume of the database file will not change, to compress the database file, you can perform a VACUUM command. VACUUM will reorganize the database from the beginning. This will use the database with an empty "free list", and the database file will be minimal.private void Comp

First, Introduction:Although SQLite database is composed of a single file, but in fact there are some hidden temporary files in SQLite runtime, these temporary files for different purposes exist, for developers, they are transparent, so in the process of development we do not need to pay attention to their existence. However, if you can have a good understanding of the mechanism and application scenarios of these temporary files, it is very helpful for us to optimize and maintain the application

[Self.database Setshouldcachestatements:yes]. This means that for each call you do not need to compile each statement again.I have never found a good guideline to use vacuum, and if the database is not regularly compressed, it will be slower. My app will run a vacuum, but only once a week (it stores the last vacuum in the nsuserdefaults and then checks for a wee

(0,4)| 1004 |li0924 (4Rows We have just removed (0,5) this record; Now let's insert this record; MyDB= Insert intoTestValues(1001,'AK'); INSERT 0 1MyDB= SelectCtid* fromtest; Ctid|Id|name-------+------+--------(0,1)| 1001 |Lottu (0,2)| 1002 |Rax (0,3)| 1003 |Xuan (0,4)| 1004 |li0924 (0,6)| 1001 |AK (5Rows Strange, why not (0,5), but (0,6) this is related to the multi-version of PostgreSQL, and the pseudo-column Cmin,cmax, with the ctid of this article is not related to, this is the characteri

languages), PL/TCL, Pl/perl, Pl/python, SQL, and C. Trigger Pre-line triggers, post-line triggers, and statement triggers are supported, and trigger statements are written in a procedural language compound statement. Pre-line triggers, post-line triggers, and statement triggers are supported, and the trigger process is written in C. System configuration File My.conf Postgresql.conf Database configuration My.conf Postgresql.

USING COVERING INDEX archivedTagUniqueID (archived=?) (~10 rows) Much better.More Performance TipsSomewhere in the Fmdb is the ability to cache statements, so when creating or opening a database, I always call [Self.database Setshouldcachestatements:yes]. This means that for each call you do not need to compile each statement again. I have never found a good guideline to use vacuum, and if the database is not regularly compressed, it will be slower.

First, Introduction: Although the SQLite database is made up of a single file, there are, in fact, some hidden temporary files that exist at the time of the SQLite runtime, which exist for different purposes and are transparent to developers, so we don't need to be concerned about their presence in the development process. However, if you have a good understanding of the mechanisms and scenarios for these temporary files, then it is very helpful for us to optimize and maintain our applications

College English Words v vacant/' veikənt/a. Empty, unoccupied, vast/va:st/a, large, massive vacuum/' vækjuəm/n, Vacuum vacuum cleaner vapour/' veipə/N. Steam, vapour vague/veig/a a vague, vague, vain/vein/a. Vain; conceit. Valid/' vælid/a. Effective, legitimate value/' vælju:/N. Value vt. Evaluation van/væn/n. Caravan, van vanish/' væniʃ/VI. Suddenly disappeared.

1. Use of explainThe explain command can view the execution plan, as already described in the previous blog. This method is our most important debugging tool.2. Update the statistics used in the execution plan in a timely manner Since statistics are not updated every time the database is operated, it is usually updated in the VACUUM, ANALYZE, CREATE Index, and so on when the DDL is executed,Therefore, the statistics used to execute the plan are likely

(specialized procedural languages), PL/TCL, Pl/perl, Pl/python, SQL, and C. Trigger Pre-line triggers, post-line triggers, and statement triggers are supported, and trigger statements are written in a procedural language compound statement. Pre-line triggers, post-line triggers, and statement triggers are supported, and the trigger process is written in C. System configuration File My.conf Postgresql.conf Database configuration

'; 5.3 Rebuilding of the Index -- If a table is updated frequently, the index performance is not good; you need to rebuild the index. Lottu=# select pg_size_pretty(pg_relation_size('ind_t_id_1')); Pg_size_pretty ---------------- 2200 kB (1 row) Lottu=# delete from t where id > 1000; DELETE 99000 Lottu=# analyze t; ANALYZE Lottu=# select pg_size_pretty(pg_relation_size('ind_t_id_1')); Pg_size_pretty ---------------- 2200 kB Lottu=# insert into t select generate_series(2000,100000),'lot

/pgsql (specialized procedural languages), PL/TCL, Pl/perl, Pl/python, SQL, and C. Trigger Pre-line triggers, post-line triggers, and statement triggers are supported, and trigger statements are written in a procedural language compound statement. Pre-line triggers, post-line triggers, and statement triggers are supported, and the trigger process is written in C. System configuration File My.conf Postgresql.conf Database configurat

the table, and the AutoIncrement property prompts the error: Database or disk is full. 3) Vacuum command and ROWID There are articles on the Internet that use vacuum command, will lead to rowid redistribution use, such as the original rowID is 1,3,5 3 records, after vacuum, will be reorganized into three-way. I personally tested it and did not reproduce it. 3.WI

PostgreSQL provides some functions to help improve performance. There are several main aspects. 1. Use the explain command to view the execution plan. In the previous blog PostgreSQL provides some functions to help improve performance. There are several main aspects. 1. Run the EXPLAIN command to view the execution plan. In the previous blog PostgreSQL provides some functions to help improve performance. There are several main aspects.1. Use EXPLAINThe EXPLAIN command can view the execution