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diff --git a/src/tools/backend/backend_dirs.html b/src/tools/backend/backend_dirs.html deleted file mode 100644 index 16bd894582e..00000000000 --- a/src/tools/backend/backend_dirs.html +++ /dev/null @@ -1,349 +0,0 @@ -<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" - "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> -<html xmlns="http://www.w3.org/1999/xhtml"> -<head> -<meta name="generator" -content="HTML Tidy for BSD/OS (vers 1st July 2002), see www.w3.org" /> -<title>PostgreSQL Backend Directories</title> -</head> -<body bgcolor="#FFFFFF" text="#000000" link="#FF0000" -vlink="#A00000" alink="#0000FF"> -<h1>PostgreSQL Backend Directories</h1> - -<h2>by Bruce Momjian</h2> - -<hr /> -<p><em>Click on any of the section headings to see the source code -for that section.</em></p> - -<h2><a id="bootstrap" name="bootstrap"></a> <a -href="../../backend/bootstrap">bootstrap</a> - creates initial -template database via initdb</h2> - -<p>Because PostgreSQL requires access to system tables for almost -every operation, getting those system tables in place is a problem. -You can't just create the tables and insert data into them in the -normal way, because table creation and insertion requires the -tables to already exist. This code <i>jams</i> the data directly -into tables using a special syntax used only by the bootstrap -procedure.</p> - -<h2><a id="main" name="main"></a> <a -href="../../backend/main">main</a> - passes control to postmaster -or postgres</h2> - -<p>This checks the process name(argv[0]) and various flags, and -passes control to the postmaster or postgres backend code.</p> - -<h2><a id="postmaster" name="postmaster"></a> <a -href="../../backend/postmaster">postmaster</a> - controls postgres -server startup/termination</h2> - -<p>This creates shared memory, and then goes into a loop waiting -for connection requests. When a connection request arrives, a -<i>postgres</i> backend is started, and the connection is passed to -it.</p> - -<h2><a id="libpq" name="libpq"></a> <a -href="../../backend/libpq">libpq</a> - backend libpq library -routines</h2> - -<p>This handles communication to the client processes.</p> - -<h2><a id="tcop" name="tcop"></a> <a -href="../../backend/tcop">tcop</a> - traffic cop, dispatches -request to proper module</h2> - -<p>This contains the <i>postgres</i> backend main handler, as well -as the code that makes calls to the parser, optimizer, executor, -and <i>/commands</i> functions.</p> - -<h2><a id="parser" name="parser"></a> <a -href="../../backend/parser">parser</a> - converts SQL query to -query tree</h2> - -<p>This converts SQL queries coming from <i>libpq</i> into -command-specific structures to be used the optimizer/executor, -or <i>/commands</i> routines. The SQL is lexically analyzed into -keywords, identifiers, and constants, and passed to the parser. The -parser creates command-specific structures to hold the elements of -the query. The command-specific structures are then broken apart, -checked, and passed to <i>/commands</i> processing routines, or -converted into <i>Lists</i> of <i>Nodes</i> to be handled by the -optimizer and executor.</p> - -<h2><a id="rewrite" name="rewrite"></a> <a -href="../../backend/rewrite">rewrite</a> - rule and views -support</h2> - -<h2><a id="optimizer" name="optimizer"></a> <a -href="../../backend/optimizer">optimizer</a> - creates path and -plan</h2> - -<p>This uses the parser output to generate an optimal plan for the -executor.</p> - -<h3><a id="optimizer_path" name="optimizer_path"></a> <a -href="../../backend/optimizer/path">optimizer/path</a> - creates -path from parser output</h3> - -<p>This takes the parser query output, and generates all possible -methods of executing the request. It examines table join order, -<i>where</i> clause restrictions, and optimizer table statistics to -evaluate each possible execution method, and assigns a cost to -each.</p> - -<h3><a id="optimizer_geqo" name="optimizer_geqo"></a> <a -href="../../backend/optimizer/geqo">optimizer/geqo</a> - genetic -query optimizer</h3> - -<p><i>optimizer/path</i> evaluates all possible ways to join the -requested tables. When the number of tables becomes great, the -number of tests made becomes great too. The Genetic Query Optimizer -considers each table separately, then figures the most optimal -order to perform the join. For a few tables, this method takes -longer, but for a large number of tables, it is faster. There is an -option to control when this feature is used.</p> - -<h3><a id="optimizer_plan" name="optimizer_plan"></a> <a -href="../../backend/optimizer/plan">optimizer/plan</a> - optimizes -path output</h3> - -<p>This takes the <i>optimizer/path</i> output, chooses the path -with the least cost, and creates a plan for the executor.</p> - -<h3><a id="optimizer_prep" name="optimizer_prep"></a> <a -href="../../backend/optimizer/prep">optimizer/prep</a> - handle -special plan cases</h3> - -<p>This does special plan processing.</p> - -<h3><a id="optimizer_util" name="optimizer_util"></a> <a -href="../../backend/optimizer/util">optimizer/util</a> - optimizer -support routines</h3> - -<p>This contains support routines used by other parts of the -optimizer.</p> - -<h2><a id="executor" name="executor"></a> <a -href="../../backend/executor">executor</a> - executes complex node -plans from optimizer</h2> - -<p>This handles <i>select, insert, update,</i> and <i>delete</i> -statements. The operations required to handle these statement types -include heap scans, index scans, sorting, joining tables, grouping, -aggregates, and uniqueness.</p> - -<h2><a id="commands" name="commands"></a> <a -href="../../backend/commands">commands</a> - commands that do not -require the executor</h2> - -<p>These process SQL commands that do not require complex handling. -It includes <i>vacuum, copy, alter, create table, create type,</i> -and many others. The code is called with the structures generated -by the parser. Most of the routines do some processing, then call -lower-level functions in the catalog directory to do the actual -work.</p> - -<h2><a id="catalog" name="catalog"></a> <a -href="../../backend/catalog">catalog</a> - system catalog -manipulation</h2> - -<p>This contains functions that manipulate the system tables or -catalogs. Table, index, procedure, operator, type, and aggregate -creation and manipulation routines are here. These are low-level -routines, and are usually called by upper routines that pre-format -user requests into a predefined format.</p> - -<h2><a id="storage" name="storage"></a> <a -href="../../backend/storage">storage</a> - manages various storage -systems</h2> - -<p>These allow uniform resource access by the backend.<br /> -<br /> - <a id="storage_buffer" name="storage_buffer"></a> <a -href="../../backend/storage/buffer">storage/buffer</a> - shared -buffer pool manager<br /> - <a id="storage_file" name="storage_file"></a> <a -href="../../backend/storage/file">storage/file</a> - file -manager<br /> - <a id="storage_freespace" name="storage_freespace"></a> <a -href="../../backend/storage/freespace">storage/freespace</a> - free -space map<br /> - <a id="storage_ipc" name="storage_ipc"></a> <a -href="../../backend/storage/ipc">storage/ipc</a> - semaphores and -shared memory<br /> - <a id="storage_large_object" name="storage_large_object"></a> <a -href="../../backend/storage/large_object">storage/large_object</a> -- large objects<br /> - <a id="storage_lmgr" name="storage_lmgr"></a> <a -href="../../backend/storage/lmgr">storage/lmgr</a> - lock -manager<br /> - <a id="storage_page" name="storage_page"></a> <a -href="../../backend/storage/page">storage/page</a> - page -manager<br /> - <a id="storage_smgr" name="storage_smgr"></a> <a -href="../../backend/storage/smgr">storage/smgr</a> - storage/disk -manager<br /> -<br /> -</p> - -<h2><a id="access" name="access"></a> <a -href="../../backend/access">access</a> - various data access -methods</h2> - -<p>These control the way data is accessed in heap, indexes, and -transactions.<br /> -<br /> - <a id="access_common" name="access_common"></a> <a -href="../../backend/access/common">access/common</a> - common -access routines<br /> - <a id="access_gist" name="access_gist"></a> <a -href="../../backend/access/gist">access/gist</a> - easy-to-define -access method system<br /> - <a id="access_hash" name="access_hash"></a> <a -href="../../backend/access/hash">access/hash</a> - hash<br /> - <a id="access_heap" name="access_heap"></a> <a -href="../../backend/access/heap">access/heap</a> - heap is use to -store data rows<br /> - <a id="access_index" name="access_index"></a> <a -href="../../backend/access/index">access/index</a> - used by all -index types<br /> - <a id="access_nbtree" name="access_nbtree"></a> <a -href="../../backend/access/nbtree">access/nbtree</a> - Lehman and -Yao's btree management algorithm<br /> - <a id="access_transam" name="access_transam"></a> <a -href="../../backend/access/transam">access/transam</a> - -transaction manager (BEGIN/ABORT/COMMIT)<br /> -<br /> -</p> - -<h2><a id="nodes" name="nodes"></a> <a -href="../../backend/nodes">nodes</a> - creation/manipulation of -nodes and lists</h2> - -<p>PostgreSQL stores information about SQL queries in structures -called nodes. <i>Nodes</i> are generic containers that have a -<i>type</i> field and then a type-specific data section. Nodes are -usually placed in <i>Lists.</i> A <i>List</i> is container with an -<i>elem</i> element, and a <i>next</i> field that points to the -next <i>List.</i> These <i>List</i> structures are chained together -in a forward linked list. In this way, a chain of <i>List</i> s can -contain an unlimited number of <i>Node</i> elements, and each -<i>Node</i> can contain any data type. These are used extensively -in the parser, optimizer, and executor to store requests and -data.</p> - -<h2><a id="utils" name="utils"></a> <a -href="../../backend/utils">utils</a> - support routines</h2> - -<h3><a id="utils_adt" name="utils_adt"></a> <a -href="../../backend/utils/adt">utils/adt</a> - built-in data type -routines</h3> - -<p>This contains all the PostgreSQL builtin data types.</p> - -<h3><a id="utils_cache" name="utils_cache"></a> <a -href="../../backend/utils/cache">utils/cache</a> - -system/relation/function cache routines</h3> - -<p>PostgreSQL supports arbitrary data types, so no data types are -hard-coded into the core backend routines. When the backend needs -to find out about a type, is does a lookup of a system table. -Because these system tables are referred to often, a cache is -maintained that speeds lookups. There is a system relation cache, a -function/operator cache, and a relation information cache. This -last cache maintains information about all recently-accessed -tables, not just system ones.</p> - -<h3><a id="utils_error" name="utils_error"></a> <a -href="../../backend/utils/error">utils/error</a> - error reporting -routines</h3> - -<p>Reports backend errors to the front end.</p> - -<h3><a id="utils_fmgr" name="utils_fmgr"></a> <a -href="../../backend/utils/fmgr">utils/fmgr</a> - function -manager</h3> - -<p>This handles the calling of dynamically-loaded functions, and -the calling of functions defined in the system tables.</p> - -<h3><a id="utils_hash" name="utils_hash"></a> <a -href="../../backend/utils/hash">utils/hash</a> - hash routines for -internal algorithms</h3> - -<p>These hash routines are used by the cache and memory-manager -routines to do quick lookups of dynamic data storage structures -maintained by the backend.</p> - -<h3><a id="utils_init" name="utils_init"></a> <a -href="../../backend/utils/init">utils/init</a> - various -initialization stuff</h3> - -<h3><a id="utils_mb" name="utils_mb"></a> <a -href="../../backend/utils/mb">utils/mb</a> - single and multibyte -encoding</h3> - -<h3><a id="utils_misc" name="utils_misc"></a> <a -href="../../backend/utils/misc">utils/misc</a> - miscellaneous -stuff</h3> - -<h3><a id="utils_mmgr" name="utils_mmgr"></a> <a -href="../../backend/utils/mmgr">utils/mmgr</a> - memory -manager(process-local memory)</h3> - -<p>When PostgreSQL allocates memory, it does so in an explicit -context. Contexts can be statement-specific, transaction-specific, -or persistent/global. By doing this, the backend can easily free -memory once a statement or transaction completes.</p> - -<h3><a id="utils_resowner" name="utils_resowner"></a> <a -href="../../backend/utils/resowner">utils/resowner</a> - resource -owner tracking</h3> - -<h3><a id="utils_sort" name="utils_sort"></a> <a -href="../../backend/utils/sort">utils/sort</a> - sort routines for -internal algorithms</h3> - -<p>When statement output must be sorted as part of a backend -operation, this code sorts the tuples, either in memory or using -disk files.</p> - -<h3><a id="utils_time" name="utils_time"></a> <a -href="../../backend/utils/time">utils/time</a> - transaction time -qualification routines</h3> - -<p>These routines do checking of tuple internal columns to -determine if the current row is still valid, or is part of a -non-committed transaction or superseded by a new row.</p> - -<h2><a id="include" name="include"></a> <a -href="../../backend/include">include</a> - include files</h2> - -<p>There are include directories for each subsystem.</p> - -<h2><a id="lib" name="lib"></a> <a href="../../backend/lib">lib</a> -- support library</h2> - -<p>This houses several generic routines.</p> - -<h2><a id="regex" name="regex"></a> <a -href="../../backend/regex">regex</a> - regular expression -library</h2> - -<p>This is used for regular expression handling in the backend, -i.e. '~'.</p> - -<h2><a id="port" name="port"></a> <a -href="../../backend/port">port</a> - compatibility routines</h2> - -<br /> - -<hr /> -<small>Maintainer: Bruce Momjian ( <a -href="mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</a> -)<br /> - Last updated: Fri May 6 14:22:27 EDT 2005</small> -</body> -</html> |