mirror of
https://github.com/postgres/postgres.git
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Update backend flowchart.
This commit is contained in:
Bruce Momjian
@@ -8,15 +8,16 @@ PostgreSQL Backend Directories
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</H1>
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<H2 ALIGN=CENTER>
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by Bruce Momjian
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</H2 ALIGN=CENTER>
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</H2>
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<P>
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<P>
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<HR>
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<EM>Click on any of the section headings to see the source code for that section.
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</EM>
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<P>
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<H2>
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<A NAME="bootstrap">
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<A HREF="../../backend/bootstrap">bootstrap</A></A>
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<A NAME="bootstrap"></A>
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<A HREF="../../backend/bootstrap">bootstrap</A>
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- creates initial template database via initdb
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</H2>
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<P>
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@@ -29,8 +30,8 @@ This code <I>jams</I> the data directly into tables using a
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special syntax used only by the bootstrap procedure.
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</P>
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<H2>
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<A NAME="main">
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<A HREF="../../backend/main">main</A></A>
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<A NAME="main"></A>
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<A HREF="../../backend/main">main</A>
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- passes control to postmaster or postgres
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</H2>
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<P>
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@@ -38,8 +39,8 @@ This checks the process name(argv[0]) and various flags, and passes
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control to the postmaster or postgres backend code.
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</P>
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<H2>
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<A NAME="postmaster">
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<A HREF="../../backend/postmaster">postmaster</A></A>
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<A NAME="postmaster"></A>
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<A HREF="../../backend/postmaster">postmaster</A>
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- controls postgres server startup/termination
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</H2>
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<P>
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@@ -49,16 +50,16 @@ When a connection request arrives, a <I>postgres</I> backend is started,
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and the connection is passed to it.
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</P>
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<H2>
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<A NAME="libpq">
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<A HREF="../../backend/libpq">libpq</A></A>
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<A NAME="libpq"></A>
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<A HREF="../../backend/libpq">libpq</A>
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- backend libpq library routines
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</H2>
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<P>
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This handles communication to the client processes.
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</P>
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<H2>
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<A NAME="tcop">
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<A HREF="../../backend/tcop">tcop</A></A>
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<A NAME="tcop"></A>
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<A HREF="../../backend/tcop">tcop</A>
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- traffic cop, dispatches request to proper module
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</H2>
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<P>
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@@ -67,8 +68,8 @@ code that makes calls to the parser, optimizer, executor, and
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<I>/commands</I> functions.
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</P>
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<H2>
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<A NAME="parser">
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<A HREF="../../backend/parser">parser</A></A>
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<A NAME="parser"></A>
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<A HREF="../../backend/parser">parser</A>
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- converts SQL query to query tree
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</H2>
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<P>
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@@ -84,19 +85,19 @@ The command-specific structures are then broken apart, checked, and passed to
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<I>Nodes</I> to be handled by the optimizer and executor.
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</P>
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<H2>
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<A NAME="optimizer">
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<A HREF="../../backend/optimizer">optimizer</A></A>
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<A NAME="optimizer"></A>
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<A HREF="../../backend/optimizer">optimizer</A>
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- creates path and plan
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</H2>
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<P>
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This uses the parser output to generate an optimal plan for the
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executor.
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</P>
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<H4>
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<A NAME="optimizer/path">
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<A HREF="../../backend/optimizer/path">optimizer/path</A></A>
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<H3>
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<A NAME="optimizer/path"></A>
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<A HREF="../../backend/optimizer/path">optimizer/path</A>
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- creates path from parser output
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</H4>
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</H3>
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<P>
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This takes the parser query output, and generates all possible methods of
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executing the request.
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@@ -104,11 +105,11 @@ It examines table join order, <I>where</I> clause restrictions,
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and optimizer table statistics to evaluate each possible execution
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method, and assigns a cost to each.
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</P>
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<H4>
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<A NAME="optimizer/geqo">
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<A HREF="../../backend/optimizer/geqo">optimizer/geqo</A></A>
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<H3>
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<A NAME="optimizer/geqo"></A>
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<A HREF="../../backend/optimizer/geqo">optimizer/geqo</A>
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- genetic query optimizer
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</H4>
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</H3>
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<P>
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<I>optimizer/path</I> evaluates all possible ways to join the requested tables.
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When the number of tables becomes great, the number of tests made
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@@ -119,34 +120,34 @@ For a few tables, this method takes longer, but for a large number of
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tables, it is faster.
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There is an option to control when this feature is used.
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</P>
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<H4>
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<A NAME="optimizer/plan">
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<A HREF="../../backend/optimizer/plan">optimizer/plan</A></A>
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<H3>
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<A NAME="optimizer/plan"></A>
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<A HREF="../../backend/optimizer/plan">optimizer/plan</A>
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- optimizes path output
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</H4>
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</H3>
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<P>
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This takes the <I>optimizer/path</I> output, chooses the path with the
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least cost, and creates a plan for the executor.
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</P>
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<H4>
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<A NAME="optimizer/prep">
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<A HREF="../../backend/optimizer/prep">optimizer/prep</A></A>
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<H3>
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<A NAME="optimizer/prep"></A>
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<A HREF="../../backend/optimizer/prep">optimizer/prep</A>
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- handle special plan cases
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</H4>
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</H3>
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<P>
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This does special plan processing.
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</P>
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<H4>
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<A NAME="optimizer/util">
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<A HREF="../../backend/optimizer/util">optimizer/util</A></A>
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<H3>
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<A NAME="optimizer/util"></A>
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<A HREF="../../backend/optimizer/util">optimizer/util</A>
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- optimizer support routines
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</H4>
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</H3>
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<P>
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This contains support routines used by other parts of the optimizer.
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</P>
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<H2>
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<A NAME="executor">
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<A HREF="../../backend/executor">executor</A></A>
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<A NAME="executor"></A>
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<A HREF="../../backend/executor">executor</A>
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- executes complex node plans from optimizer
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</H2>
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<P>
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@@ -156,8 +157,8 @@ heap scans, index scans, sorting, joining tables, grouping, aggregates,
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and uniqueness.
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</P>
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<H2>
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<A NAME="commands">
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<A HREF="../../backend/commands">commands</A></A>
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<A NAME="commands"></A>
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<A HREF="../../backend/commands">commands</A>
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- commands that do not require the executor
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</H2>
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<P>
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@@ -169,8 +170,8 @@ Most of the routines do some processing, then call lower-level functions
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in the catalog directory to do the actual work.
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</P>
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<H2>
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<A NAME="catalog">
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<A HREF="../../backend/catalog">catalog</A></A>
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<A NAME="catalog"></A>
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<A HREF="../../backend/catalog">catalog</A>
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- system catalog manipulation
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</H2>
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<P>
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@@ -181,47 +182,47 @@ These are low-level routines, and are usually called by upper routines
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that pre-format user requests into a predefined format.
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</P>
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<H2>
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<A NAME="storage">
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<A HREF="../../backend/storage">storage</A></A>
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<A NAME="storage"></A>
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<A HREF="../../backend/storage">storage</A>
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- manages various storage systems
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</H2>
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<P>
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These allow uniform resource access by the backend.
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<BR>
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<BR>
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<A NAME="storage/buffer">
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<A HREF="../../backend/storage/buffer">storage/buffer</A></A>
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<A NAME="storage/buffer"></A>
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<A HREF="../../backend/storage/buffer">storage/buffer</A>
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- shared buffer pool manager
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<BR>
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<A NAME="storage/file">
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<A HREF="../../backend/storage/file">storage/file</A></A>
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<A NAME="storage/file"></A>
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<A HREF="../../backend/storage/file">storage/file</A>
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- file manager
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<BR>
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<A NAME="storage/ipc">
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<A HREF="../../backend/storage/ipc">storage/ipc</A></A>
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<A NAME="storage/ipc"></A>
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<A HREF="../../backend/storage/ipc">storage/ipc</A>
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- semaphores and shared memory
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<BR>
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<A NAME="storage/large_object">
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<A HREF="../../backend/storage/large_object">storage/large_object</A></A>
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<A NAME="storage/large_object"></A>
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<A HREF="../../backend/storage/large_object">storage/large_object</A>
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- large objects
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<BR>
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<A NAME="storage/lmgr">
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<A HREF="../../backend/storage/lmgr">storage/lmgr</A></A>
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<A NAME="storage/lmgr"></A>
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<A HREF="../../backend/storage/lmgr">storage/lmgr</A>
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- lock manager
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<BR>
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<A NAME="storage/page">
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<A HREF="../../backend/storage/page">storage/page</A></A>
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<A NAME="storage/page"></A>
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<A HREF="../../backend/storage/page">storage/page</A>
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- page manager
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<BR>
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<A NAME="storage/smgr">
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<A HREF="../../backend/storage/smgr">storage/smgr</A></A>
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<A NAME="storage/smgr"></A>
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<A HREF="../../backend/storage/smgr">storage/smgr</A>
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- storage/disk manager
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<BR>
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<BR>
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</P>
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<H2>
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<A NAME="access">
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<A HREF="../../backend/access">access</A></A>
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<A NAME="access"></A>
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<A HREF="../../backend/access">access</A>
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- various data access methods
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</H2>
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<P>
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@@ -229,43 +230,43 @@ These control the way data is accessed in heap, indexes, and
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transactions.
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<BR>
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<BR>
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<A NAME="access/common">
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<A HREF="../../backend/access/common">access/common</A></A>
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<A NAME="access/common"></A>
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<A HREF="../../backend/access/common">access/common</A>
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- common access routines
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<BR>
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<A NAME="access/gist">
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<A HREF="../../backend/access/gist">access/gist</A></A>
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<A NAME="access/gist"></A>
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||||
<A HREF="../../backend/access/gist">access/gist</A>
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- easy-to-define access method system
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<BR>
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<A NAME="access/hash">
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||||
<A HREF="../../backend/access/hash">access/hash</A></A>
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<A NAME="access/hash"></A>
|
||||
<A HREF="../../backend/access/hash">access/hash</A>
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- hash
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<BR>
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<A NAME="access/heap">
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<A HREF="../../backend/access/heap">access/heap</A></A>
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<A NAME="access/heap"></A>
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<A HREF="../../backend/access/heap">access/heap</A>
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- heap is use to store data rows
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<BR>
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<A NAME="access/index">
|
||||
<A HREF="../../backend/access/index">access/index</A></A>
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||||
<A NAME="access/index"></A>
|
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<A HREF="../../backend/access/index">access/index</A>
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- used by all index types
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<BR>
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<A NAME="access/nbtree">
|
||||
<A HREF="../../backend/access/nbtree">access/nbtree</A></A>
|
||||
<A NAME="access/nbtree"></A>
|
||||
<A HREF="../../backend/access/nbtree">access/nbtree</A>
|
||||
- Lehman and Yao's btree management algorithm
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<BR>
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<A NAME="access/rtree">
|
||||
<A HREF="../../backend/access/rtree">access/rtree</A></A>
|
||||
<A NAME="access/rtree"></A>
|
||||
<A HREF="../../backend/access/rtree">access/rtree</A>
|
||||
- used for indexing of 2-dimensional data
|
||||
<BR>
|
||||
<A NAME="access/transam">
|
||||
<A HREF="../../backend/access/transam">access/transam</A></A>
|
||||
<A NAME="access/transam"></A>
|
||||
<A HREF="../../backend/access/transam">access/transam</A>
|
||||
- transaction manager (BEGIN/ABORT/COMMIT)
|
||||
<BR>
|
||||
<BR>
|
||||
</P>
|
||||
<H2>
|
||||
<A NAME="nodes">
|
||||
<A HREF="../../backend/nodes">nodes</A></A>
|
||||
<A NAME="nodes"></A>
|
||||
<A HREF="../../backend/nodes">nodes</A>
|
||||
- creation/manipulation of nodes and lists
|
||||
</H2>
|
||||
<P>
|
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@@ -283,23 +284,23 @@ These are used extensively in the parser, optimizer, and executor to
|
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store requests and data.
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</P>
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||||
<H2>
|
||||
<A NAME="utils">
|
||||
<A HREF="../../backend/utils">utils</A></A>
|
||||
<A NAME="utils"></A>
|
||||
<A HREF="../../backend/utils">utils</A>
|
||||
- support routines
|
||||
</H2>
|
||||
<H4>
|
||||
<A NAME="utils/adt">
|
||||
<A HREF="../../backend/utils/adt">utils/adt</A></A>
|
||||
<H3>
|
||||
<A NAME="utils/adt"></A>
|
||||
<A HREF="../../backend/utils/adt">utils/adt</A>
|
||||
- built-in data type routines
|
||||
</H4>
|
||||
</H3>
|
||||
<P>
|
||||
This contains all the PostgreSQL builtin data types.
|
||||
</P>
|
||||
<H4>
|
||||
<A NAME="utils/cache">
|
||||
<A HREF="../../backend/utils/cache">utils/cache</A></A>
|
||||
<H3>
|
||||
<A NAME="utils/cache"></A>
|
||||
<A HREF="../../backend/utils/cache">utils/cache</A>
|
||||
- system/relation/function cache routines
|
||||
</H4>
|
||||
</H3>
|
||||
<P>
|
||||
PostgreSQL supports arbitrary data types, so no data types are hard-coded
|
||||
into the core backend routines.
|
||||
@@ -312,48 +313,48 @@ information cache.
|
||||
This last cache maintains information about all recently-accessed
|
||||
tables, not just system ones.
|
||||
</P>
|
||||
<H4>
|
||||
<A NAME="utils/error">
|
||||
<A HREF="../../backend/utils/error">utils/error</A></A>
|
||||
<H3>
|
||||
<A NAME="utils/error"></A>
|
||||
<A HREF="../../backend/utils/error">utils/error</A>
|
||||
- error reporting routines
|
||||
</H4>
|
||||
</H3>
|
||||
<P>
|
||||
Reports backend errors to the front end.
|
||||
</P>
|
||||
<H4>
|
||||
<A NAME="utils/fmgr">
|
||||
<A HREF="../../backend/utils/fmgr">utils/fmgr</A></A>
|
||||
<H3>
|
||||
<A NAME="utils/fmgr"></A>
|
||||
<A HREF="../../backend/utils/fmgr">utils/fmgr</A>
|
||||
- function manager
|
||||
</H4>
|
||||
</H3>
|
||||
<P>
|
||||
This handles the calling of dynamically-loaded functions, and the calling
|
||||
of functions defined in the system tables.
|
||||
</P>
|
||||
<H4>
|
||||
<A NAME="utils/hash">
|
||||
<A HREF="../../backend/utils/hash">utils/hash</A></A>
|
||||
<H3>
|
||||
<A NAME="utils/hash"></A>
|
||||
<A HREF="../../backend/utils/hash">utils/hash</A>
|
||||
- hash routines for internal algorithms
|
||||
</H4>
|
||||
</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>
|
||||
<H4>
|
||||
<A NAME="utils/init">
|
||||
<A HREF="../../backend/utils/init">utils/init</A></A>
|
||||
<H3>
|
||||
<A NAME="utils/init"></A>
|
||||
<A HREF="../../backend/utils/init">utils/init</A>
|
||||
- various initialization stuff
|
||||
</H4>
|
||||
<H4>
|
||||
<A NAME="utils/misc">
|
||||
<A HREF="../../backend/utils/misc">utils/misc</A></A>
|
||||
</H3>
|
||||
<H3>
|
||||
<A NAME="utils/misc"></A>
|
||||
<A HREF="../../backend/utils/misc">utils/misc</A>
|
||||
- miscellaneous stuff
|
||||
</H4>
|
||||
<H4>
|
||||
<A NAME="utils/mmgr">
|
||||
<A HREF="../../backend/utils/mmgr">utils/mmgr</A></A>
|
||||
</H3>
|
||||
<H3>
|
||||
<A NAME="utils/mmgr"></A>
|
||||
<A HREF="../../backend/utils/mmgr">utils/mmgr</A>
|
||||
- memory manager(process-local memory)
|
||||
</H4>
|
||||
</H3>
|
||||
<P>
|
||||
When PostgreSQL allocates memory, it does so in an explicit context.
|
||||
Contexts can be statement-specific, transaction-specific, or
|
||||
@@ -361,65 +362,70 @@ persistent/global.
|
||||
By doing this, the backend can easily free memory once a statement or
|
||||
transaction completes.
|
||||
</P>
|
||||
<H4>
|
||||
<A NAME="utils/sort">
|
||||
<A HREF="../../backend/utils/sort">utils/sort</A></A>
|
||||
<H3>
|
||||
<A NAME="utils/sort"></A>
|
||||
<A HREF="../../backend/utils/sort">utils/sort</A>
|
||||
- sort routines for internal algorithms
|
||||
</H4>
|
||||
</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>
|
||||
<H4>
|
||||
<A NAME="utils/time">
|
||||
<A HREF="../../backend/utils/time">utils/time</A></A>
|
||||
<H3>
|
||||
<A NAME="utils/time"></A>
|
||||
<A HREF="../../backend/utils/time">utils/time</A>
|
||||
- transaction time qualification routines
|
||||
</H4>
|
||||
</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 NAME="include">
|
||||
<A HREF="../../backend/include">include</A></A>
|
||||
<A NAME="include"></A>
|
||||
<A HREF="../../backend/include">include</A>
|
||||
- include files
|
||||
</H2>
|
||||
<P>
|
||||
There are include directories for each subsystem.
|
||||
</P>
|
||||
<H2>
|
||||
<A NAME="lib">
|
||||
<A HREF="../../backend/lib">lib</A></A>
|
||||
<A NAME="lib"></A>
|
||||
<A HREF="../../backend/lib">lib</A>
|
||||
- support library
|
||||
</H2>
|
||||
<P>
|
||||
This houses several generic routines.
|
||||
</P>
|
||||
<H2>
|
||||
<A NAME="regex">
|
||||
<A HREF="../../backend/regex">regex</A></A>
|
||||
<A 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 NAME="rewrite">
|
||||
<A HREF="../../backend/rewrite">rewrite</A></A>
|
||||
<A NAME="rewrite"></A>
|
||||
<A HREF="../../backend/rewrite">rewrite</A>
|
||||
- rules system
|
||||
</H2>
|
||||
<P>
|
||||
This does processing for the rules system.
|
||||
</P>
|
||||
<H2>
|
||||
<A NAME="tioga">
|
||||
<A HREF="../../backend/tioga">tioga</A></A>
|
||||
<A NAME="tioga"></A>
|
||||
<A HREF="../../backend/tioga">tioga</A>
|
||||
- unused (array handling?)
|
||||
</H2>
|
||||
<HR>
|
||||
<BR>
|
||||
<HR SIZE="2" NOSHADE>
|
||||
<SMALL>
|
||||
<ADDRESS>
|
||||
Maintainer: Bruce Momjian<A
|
||||
HREF="mailto:maillist@candle.pha.pa.us">maillist@candle.pha.pa.us</a>)<BR>
|
||||
Last updated: Mon Oct 27 11:01:08 EST 1997
|
||||
Maintainer: Bruce Momjian (<A
|
||||
HREF="mailto:maillist@candle.pha.pa.us">maillist@candle.pha.pa.us</A>)<BR>
|
||||
Last updated: Tue Dec 9 17:56:08 EST 1997
|
||||
</ADDRESS>
|
||||
</SMALL>
|
||||
</BODY>
|
||||
</HTML>
|
||||
|
||||
Reference in New Issue
Block a user