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Functions for Receiving COPY DataManual ChaptersPG1832.10.2. Functions for Receiving COPY Data These functions are used to receive data during COPY TO STDOUT. They will fail if called when the connection is not in COPY_OUT state. PQgetCopyDat…Functions for Receiving COPY Data Functions for Sending Cancel RequestsManual ChaptersPG1832.7.1. Functions for Sending Cancel Requests PQcancelCreate Prepares a connection over which a cancel request can be sent. PGcancelConn *PQcancelCreate(PGconn *conn); PQcancelCreate creates…Functions for Sending Cancel Requests Functions for Sending COPY DataManual ChaptersPG1832.10.1. Functions for Sending COPY Data These functions are used to send data during COPY FROM STDIN. They will fail if called when the connection is not in COPY_IN state. PQputCopyData # S…Functions for Sending COPY Data Functions ProvidedManual ChaptersPG18F.42.1. Functions Provided ssl_is_used() returns boolean Returns true if current connection to server uses SSL, and false otherwise. ssl_version() returns text Returns the name of the protoc…Functions Provided Functions ProvidedManual ChaptersPG18F.43.1. Functions Provided Table F.33 summarizes the functions provided by the tablefunc module. Table F.33. tablefunc Functions Function Description normal_rand ( numvals integer, mean floa…Functions Provided Further InformationManual ChaptersPG184. Further Information Besides the documentation, that is, this book, there are other resources about PostgreSQL: Wiki The PostgreSQL wiki contains the project's FAQ (Frequently Asked Questi…Further Information Further ReadingManual ChaptersPG1861.4. Further Reading The following resources contain additional information about genetic algorithms: The Hitch-Hiker's Guide to Evolutionary Computation, (FAQ for news://comp.ai.genetic) E…Further Reading Further ReadingManual ChaptersPG1823.3.5. Further Reading These are good sources to start learning about various kinds of encoding systems. CJKV Information Processing: Chinese, Japanese, Korean & Vietnamese Computing Contai…Further Reading Future Implementation Tasks for PostgreSQL GEQOManual ChaptersPG1861.3.2. Future Implementation Tasks for PostgreSQL GEQO Work is still needed to improve the genetic algorithm parameter settings. In file src/backend/optimizer/geqo/geqo_main.c, routines gim…Future Implementation Tasks for PostgreSQL GEQO fuzzystrmatch — determine string similarities and distanceManual ChaptersPG18F.16. fuzzystrmatch — determine string similarities and distance The fuzzystrmatch module provides several functions to determine similarities and distance between strings. Caution At presen…fuzzystrmatch — determine string similarities and distance Gathering Document StatisticsManual ChaptersPG1812.4.4. Gathering Document Statistics The function ts_stat is useful for checking your configuration and for finding stop-word candidates. ts_stat(sqlquery text, [ weights text, ] OUT word t…Gathering Document Statistics gen_salt()Manual ChaptersPG18F.26.2.2. gen_salt() gen_salt(type text [, iter_count integer ]) returns text Generates a new random salt string for use in crypt(). The salt string also tells crypt() which algorithm to use…gen_salt() GeneralManual ChaptersPG1836.10.6.1. General The PostgreSQL server contains several well-demarcated APIs for server plugins, such as the function manager (fmgr, described in this chapter), SPI (Chapter 45), and vario…General General Coding GuidelinesManual ChaptersPG1850.1.2. General Coding Guidelines Developers should keep the following in mind when implementing token validation: Token Confidentiality Modules should not write tokens, or pieces of tokens,…General Coding Guidelines General FunctionsManual ChaptersPG18F.23.1. General Functions get_raw_page(relname text, fork text, blkno bigint) returns bytea get_raw_page reads the specified block of the named relation and returns a copy as a bytea value. …General Functions General FunctionsManual ChaptersPG18F.37.1. General Functions pg_get_wal_record_info(in_lsn pg_lsn) returns record # Gets WAL record information about a record that is located at or after the in_lsn argument. For example: post…General Functions General Hashing FunctionsManual ChaptersPG18F.26.1. General Hashing FunctionsGeneral Hashing Functions General PerformanceManual ChaptersPG18E.6.3.1.3. General Performance Add an asynchronous I/O subsystem (Andres Freund, Thomas Munro, Nazir Bilal Yavuz, Melanie Plageman) § § § § § § § § § § § This feature allows backends to queu…General Performance General PurposeManual ChaptersPG18General Purpose -B nbuffers Sets the number of shared buffers for use by the server processes. The default value of this parameter is chosen automatically by initdb. Specifying this option i…General Purpose Generated Column ReplicationManual ChaptersPG1829.6. Generated Column Replication Typically, a table at the subscriber will be defined the same as the publisher table, so if the publisher table has a GENERATED column then the subscriber …Generated Column Replication Generated ColumnsManual ChaptersPG185.4. Generated Columns A generated column is a special column that is always computed from other columns. Thus, it is for columns what a view is for tables. There are two kinds of generated …Generated Columns Generated ColumnsManual ChaptersPG18Generated Columns The options STORED and VIRTUAL are not standard but are also used by other SQL implementations. The SQL standard does not specify the storage of generated columns.Generated Columns Generating PGP Keys with GnuPGManual ChaptersPG18F.26.3.9. Generating PGP Keys with GnuPG To generate a new key: gpg --gen-key The preferred key type is “DSA and Elgamal”. For RSA encryption you must create either DSA or RSA sign-only key …Generating PGP Keys with GnuPG Generating Possible PlansManual ChaptersPG1851.5.1. Generating Possible Plans The planner/optimizer starts by generating plans for scanning each individual relation (table) used in the query. The possible plans are determined by the a…Generating Possible Plans Generating Possible Plans with GEQOManual ChaptersPG1861.3.1. Generating Possible Plans with GEQO The GEQO planning process uses the standard planner code to generate plans for scans of individual relations. Then join plans are developed using …Generating Possible Plans with GEQO Generic File Access FunctionsManual ChaptersPG189.28.9. Generic File Access Functions The functions shown in Table 9.108 provide native access to files on the machine hosting the server. Only files within the database cluster directory an…Generic File Access Functions Generic Message CallbackManual ChaptersPG1847.6.4.8. Generic Message Callback The optional message_cb callback is called whenever a logical decoding message has been decoded. typedef void (*LogicalDecodeMessageCB) (struct LogicalDeco…Generic Message Callback Generic WAL RecordsManual ChaptersPG1864.1. Generic WAL Records Although all built-in WAL-logged modules have their own types of WAL records, there is also a generic WAL record type, which describes changes to pages in a generic…Generic WAL Records Genetic AlgorithmsManual ChaptersPG1861.2. Genetic Algorithms The genetic algorithm (GA) is a heuristic optimization method which operates through randomized search. The set of possible solutions for the optimization problem is…Genetic Algorithms Genetic Query Optimization (GEQO) in PostgreSQLManual ChaptersPG1861.3. Genetic Query Optimization (GEQO) in PostgreSQL The GEQO module approaches the query optimization problem as though it were the well-known traveling salesman problem (TSP). Possible qu…Genetic Query Optimization (GEQO) in PostgreSQL Genetic Query OptimizerManual ChaptersPG18Chapter 61. Genetic Query Optimizer Author Written by Martin Utesch (<utesch@aut.tu-freiberg.de>) for the Institute of Automatic Control at the University of Mining and Technology in Freiber…Genetic Query Optimizer Genetic Query OptimizerManual ChaptersPG1819.7.3. Genetic Query Optimizer The genetic query optimizer (GEQO) is an algorithm that does query planning using heuristic searching. This reduces planning time for complex queries (those j…Genetic Query Optimizer Geometric Functions and OperatorsManual ChaptersPG189.11. Geometric Functions and Operators The geometric types point, box, lseg, line, path, polygon, and circle have a large set of native support functions and operators, shown in Table 9.36,…Geometric Functions and Operators Geometric TypesManual ChaptersPG188.8. Geometric Types Geometric data types represent two-dimensional spatial objects. Table 8.20 shows the geometric types available in PostgreSQL. Table 8.20. Geometric Types Name Storage Si…Geometric Types GET DESCRIPTORManual ChaptersPG18GET DESCRIPTOR GET DESCRIPTOR — get information from an SQL descriptor area Synopsis GET DESCRIPTOR descriptor_name :cvariable = descriptor_header_item GET DESCRIPTOR descriptor_name VALUE c…GET DESCRIPTOR Getting StartedManual ChaptersPG18Chapter 1. Getting StartedGetting Started Getting the SourceManual ChaptersPG1817.2. Getting the Source The PostgreSQL source code for released versions can be obtained from the download section of our website: https://www.postgresql.org/ftp/source/. Download the postg…Getting the Source Getting the Source via GitManual ChaptersPG18I.1. Getting the Source via Git With Git you will make a copy of the entire code repository on your local machine, so you will have access to all history and branches offline. This is the fa…Getting the Source via Git GINManual ChaptersPG1811.2.5. GIN GIN indexes are “inverted indexes” which are appropriate for data values that contain multiple component values, such as arrays. An inverted index contains a separate entry for e…GIN GIN Fast Update TechniqueManual ChaptersPG1865.4.4.1. GIN Fast Update Technique Updating a GIN index tends to be slow because of the intrinsic nature of inverted indexes: inserting or updating one heap row can cause many inserts into …GIN Fast Update Technique