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Postgres FD Implementation
Commit 0f3748a2 authored by Bruce Momjian's avatar Bruce Momjian
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Attached patch cleans up the HTML code in tools/backend. This is 

required for us to pull it into the main website. Same kind of fixes as
last time, just make sure things aren't violating the HTML standard. No
context changes at all.

Magnus Hagander
parent e6557e9a
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src/tools/backend/backend_dirs.html
View file @ 0f3748a2
...@@ -3,18 +3,17 @@ ...@@ -3,18 +3,17 @@
<TITLE>PostgreSQL Backend Directories</TITLE> <TITLE>PostgreSQL Backend Directories</TITLE>
</HEAD> </HEAD>
<BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#FF0000" VLINK="#A00000" ALINK="#0000FF"> <BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#FF0000" VLINK="#A00000" ALINK="#0000FF">
<H1 ALIGN=CENTER> <H1>
PostgreSQL Backend Directories PostgreSQL Backend Directories
</H1> </H1>
<H2 ALIGN=CENTER> <H2>
by Bruce Momjian by Bruce Momjian
</H2> </H2>
<P>
<P>
<HR> <HR>
<P>
<EM>Click on any of the section headings to see the source code for that section. <EM>Click on any of the section headings to see the source code for that section.
</EM> </EM>
<P> </P>
<H2> <H2>
<A NAME="bootstrap"></A> <A NAME="bootstrap"></A>
<A HREF="../../backend/bootstrap">bootstrap</A> <A HREF="../../backend/bootstrap">bootstrap</A>
...@@ -94,7 +93,7 @@ This uses the parser output to generate an optimal plan for the ...@@ -94,7 +93,7 @@ This uses the parser output to generate an optimal plan for the
executor. executor.
</P> </P>
<H3> <H3>
<A NAME="optimizer/path"></A> <A NAME="optimizer_path"></A>
<A HREF="../../backend/optimizer/path">optimizer/path</A> <A HREF="../../backend/optimizer/path">optimizer/path</A>
- creates path from parser output - creates path from parser output
</H3> </H3>
...@@ -106,7 +105,7 @@ and optimizer table statistics to evaluate each possible execution ...@@ -106,7 +105,7 @@ and optimizer table statistics to evaluate each possible execution
method, and assigns a cost to each. method, and assigns a cost to each.
</P> </P>
<H3> <H3>
<A NAME="optimizer/geqo"></A> <A NAME="optimizer_geqo"></A>
<A HREF="../../backend/optimizer/geqo">optimizer/geqo</A> <A HREF="../../backend/optimizer/geqo">optimizer/geqo</A>
- genetic query optimizer - genetic query optimizer
</H3> </H3>
...@@ -121,7 +120,7 @@ tables, it is faster. ...@@ -121,7 +120,7 @@ tables, it is faster.
There is an option to control when this feature is used. There is an option to control when this feature is used.
</P> </P>
<H3> <H3>
<A NAME="optimizer/plan"></A> <A NAME="optimizer_plan"></A>
<A HREF="../../backend/optimizer/plan">optimizer/plan</A> <A HREF="../../backend/optimizer/plan">optimizer/plan</A>
- optimizes path output - optimizes path output
</H3> </H3>
...@@ -130,7 +129,7 @@ This takes the <I>optimizer/path</I> output, chooses the path with the ...@@ -130,7 +129,7 @@ This takes the <I>optimizer/path</I> output, chooses the path with the
least cost, and creates a plan for the executor. least cost, and creates a plan for the executor.
</P> </P>
<H3> <H3>
<A NAME="optimizer/prep"></A> <A NAME="optimizer_prep"></A>
<A HREF="../../backend/optimizer/prep">optimizer/prep</A> <A HREF="../../backend/optimizer/prep">optimizer/prep</A>
- handle special plan cases - handle special plan cases
</H3> </H3>
...@@ -138,7 +137,7 @@ least cost, and creates a plan for the executor. ...@@ -138,7 +137,7 @@ least cost, and creates a plan for the executor.
This does special plan processing. This does special plan processing.
</P> </P>
<H3> <H3>
<A NAME="optimizer/util"></A> <A NAME="optimizer_util"></A>
<A HREF="../../backend/optimizer/util">optimizer/util</A> <A HREF="../../backend/optimizer/util">optimizer/util</A>
- optimizer support routines - optimizer support routines
</H3> </H3>
...@@ -190,31 +189,31 @@ that pre-format user requests into a predefined format. ...@@ -190,31 +189,31 @@ that pre-format user requests into a predefined format.
These allow uniform resource access by the backend. These allow uniform resource access by the backend.
<BR> <BR>
<BR> <BR>
<A NAME="storage/buffer"></A> <A NAME="storage_buffer"></A>
<A HREF="../../backend/storage/buffer">storage/buffer</A> <A HREF="../../backend/storage/buffer">storage/buffer</A>
- shared buffer pool manager - shared buffer pool manager
<BR> <BR>
<A NAME="storage/file"></A> <A NAME="storage_file"></A>
<A HREF="../../backend/storage/file">storage/file</A> <A HREF="../../backend/storage/file">storage/file</A>
- file manager - file manager
<BR> <BR>
<A NAME="storage/ipc"></A> <A NAME="storage_ipc"></A>
<A HREF="../../backend/storage/ipc">storage/ipc</A> <A HREF="../../backend/storage/ipc">storage/ipc</A>
- semaphores and shared memory - semaphores and shared memory
<BR> <BR>
<A NAME="storage/large_object"></A> <A NAME="storage_large_object"></A>
<A HREF="../../backend/storage/large_object">storage/large_object</A> <A HREF="../../backend/storage/large_object">storage/large_object</A>
- large objects - large objects
<BR> <BR>
<A NAME="storage/lmgr"></A> <A NAME="storage_lmgr"></A>
<A HREF="../../backend/storage/lmgr">storage/lmgr</A> <A HREF="../../backend/storage/lmgr">storage/lmgr</A>
- lock manager - lock manager
<BR> <BR>
<A NAME="storage/page"></A> <A NAME="storage_page"></A>
<A HREF="../../backend/storage/page">storage/page</A> <A HREF="../../backend/storage/page">storage/page</A>
- page manager - page manager
<BR> <BR>
<A NAME="storage/smgr"></A> <A NAME="storage_smgr"></A>
<A HREF="../../backend/storage/smgr">storage/smgr</A> <A HREF="../../backend/storage/smgr">storage/smgr</A>
- storage/disk manager - storage/disk manager
<BR> <BR>
...@@ -230,35 +229,35 @@ These control the way data is accessed in heap, indexes, and ...@@ -230,35 +229,35 @@ These control the way data is accessed in heap, indexes, and
transactions. transactions.
<BR> <BR>
<BR> <BR>
<A NAME="access/common"></A> <A NAME="access_common"></A>
<A HREF="../../backend/access/common">access/common</A> <A HREF="../../backend/access/common">access/common</A>
- common access routines - common access routines
<BR> <BR>
<A NAME="access/gist"></A> <A NAME="access_gist"></A>
<A HREF="../../backend/access/gist">access/gist</A> <A HREF="../../backend/access/gist">access/gist</A>
- easy-to-define access method system - easy-to-define access method system
<BR> <BR>
<A NAME="access/hash"></A> <A NAME="access_hash"></A>
<A HREF="../../backend/access/hash">access/hash</A> <A HREF="../../backend/access/hash">access/hash</A>
- hash - hash
<BR> <BR>
<A NAME="access/heap"></A> <A NAME="access_heap"></A>
<A HREF="../../backend/access/heap">access/heap</A> <A HREF="../../backend/access/heap">access/heap</A>
- heap is use to store data rows - heap is use to store data rows
<BR> <BR>
<A NAME="access/index"></A> <A NAME="access_index"></A>
<A HREF="../../backend/access/index">access/index</A> <A HREF="../../backend/access/index">access/index</A>
- used by all index types - used by all index types
<BR> <BR>
<A NAME="access/nbtree"></A> <A NAME="access_nbtree"></A>
<A HREF="../../backend/access/nbtree">access/nbtree</A> <A HREF="../../backend/access/nbtree">access/nbtree</A>
- Lehman and Yao's btree management algorithm - Lehman and Yao's btree management algorithm
<BR> <BR>
<A NAME="access/rtree"></A> <A NAME="access_rtree"></A>
<A HREF="../../backend/access/rtree">access/rtree</A> <A HREF="../../backend/access/rtree">access/rtree</A>
- used for indexing of 2-dimensional data - used for indexing of 2-dimensional data
<BR> <BR>
<A NAME="access/transam"></A> <A NAME="access_transam"></A>
<A HREF="../../backend/access/transam">access/transam</A> <A HREF="../../backend/access/transam">access/transam</A>
- transaction manager (BEGIN/ABORT/COMMIT) - transaction manager (BEGIN/ABORT/COMMIT)
<BR> <BR>
...@@ -289,7 +288,7 @@ store requests and data. ...@@ -289,7 +288,7 @@ store requests and data.
- support routines - support routines
</H2> </H2>
<H3> <H3>
<A NAME="utils/adt"></A> <A NAME="utils_adt"></A>
<A HREF="../../backend/utils/adt">utils/adt</A> <A HREF="../../backend/utils/adt">utils/adt</A>
- built-in data type routines - built-in data type routines
</H3> </H3>
...@@ -297,7 +296,7 @@ store requests and data. ...@@ -297,7 +296,7 @@ store requests and data.
This contains all the PostgreSQL builtin data types. This contains all the PostgreSQL builtin data types.
</P> </P>
<H3> <H3>
<A NAME="utils/cache"></A> <A NAME="utils_cache"></A>
<A HREF="../../backend/utils/cache">utils/cache</A> <A HREF="../../backend/utils/cache">utils/cache</A>
- system/relation/function cache routines - system/relation/function cache routines
</H3> </H3>
...@@ -314,7 +313,7 @@ This last cache maintains information about all recently-accessed ...@@ -314,7 +313,7 @@ This last cache maintains information about all recently-accessed
tables, not just system ones. tables, not just system ones.
</P> </P>
<H3> <H3>
<A NAME="utils/error"></A> <A NAME="utils_error"></A>
<A HREF="../../backend/utils/error">utils/error</A> <A HREF="../../backend/utils/error">utils/error</A>
- error reporting routines - error reporting routines
</H3> </H3>
...@@ -322,7 +321,7 @@ tables, not just system ones. ...@@ -322,7 +321,7 @@ tables, not just system ones.
Reports backend errors to the front end. Reports backend errors to the front end.
</P> </P>
<H3> <H3>
<A NAME="utils/fmgr"></A> <A NAME="utils_fmgr"></A>
<A HREF="../../backend/utils/fmgr">utils/fmgr</A> <A HREF="../../backend/utils/fmgr">utils/fmgr</A>
- function manager - function manager
</H3> </H3>
...@@ -331,7 +330,7 @@ This handles the calling of dynamically-loaded functions, and the calling ...@@ -331,7 +330,7 @@ This handles the calling of dynamically-loaded functions, and the calling
of functions defined in the system tables. of functions defined in the system tables.
</P> </P>
<H3> <H3>
<A NAME="utils/hash"></A> <A NAME="utils_hash"></A>
<A HREF="../../backend/utils/hash">utils/hash</A> <A HREF="../../backend/utils/hash">utils/hash</A>
- hash routines for internal algorithms - hash routines for internal algorithms
</H3> </H3>
...@@ -341,17 +340,17 @@ do quick lookups of dynamic data storage structures maintained by the ...@@ -341,17 +340,17 @@ do quick lookups of dynamic data storage structures maintained by the
backend. backend.
</P> </P>
<H3> <H3>
<A NAME="utils/init"></A> <A NAME="utils_init"></A>
<A HREF="../../backend/utils/init">utils/init</A> <A HREF="../../backend/utils/init">utils/init</A>
- various initialization stuff - various initialization stuff
</H3> </H3>
<H3> <H3>
<A NAME="utils/misc"></A> <A NAME="utils_misc"></A>
<A HREF="../../backend/utils/misc">utils/misc</A> <A HREF="../../backend/utils/misc">utils/misc</A>
- miscellaneous stuff - miscellaneous stuff
</H3> </H3>
<H3> <H3>
<A NAME="utils/mmgr"></A> <A NAME="utils_mmgr"></A>
<A HREF="../../backend/utils/mmgr">utils/mmgr</A> <A HREF="../../backend/utils/mmgr">utils/mmgr</A>
- memory manager(process-local memory) - memory manager(process-local memory)
</H3> </H3>
...@@ -363,7 +362,7 @@ By doing this, the backend can easily free memory once a statement or ...@@ -363,7 +362,7 @@ By doing this, the backend can easily free memory once a statement or
transaction completes. transaction completes.
</P> </P>
<H3> <H3>
<A NAME="utils/sort"></A> <A NAME="utils_sort"></A>
<A HREF="../../backend/utils/sort">utils/sort</A> <A HREF="../../backend/utils/sort">utils/sort</A>
- sort routines for internal algorithms - sort routines for internal algorithms
</H3> </H3>
...@@ -372,7 +371,7 @@ When statement output must be sorted as part of a backend operation, ...@@ -372,7 +371,7 @@ When statement output must be sorted as part of a backend operation,
this code sorts the tuples, either in memory or using disk files. this code sorts the tuples, either in memory or using disk files.
</P> </P>
<H3> <H3>
<A NAME="utils/time"></A> <A NAME="utils_time"></A>
<A HREF="../../backend/utils/time">utils/time</A> <A HREF="../../backend/utils/time">utils/time</A>
- transaction time qualification routines - transaction time qualification routines
</H3> </H3>
...@@ -419,13 +418,11 @@ This does processing for the rules system. ...@@ -419,13 +418,11 @@ This does processing for the rules system.
- unused (array handling?) - unused (array handling?)
</H2> </H2>
<BR> <BR>
<HR SIZE="2" NOSHADE> <HR>
<SMALL> <SMALL>
<ADDRESS>
Maintainer: Bruce Momjian (<A Maintainer: Bruce Momjian (<A
HREF="mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR> HREF="mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
Last updated: Tue Dec 9 17:56:08 EST 1997 Last updated: Tue Dec 9 17:56:08 EST 1997
</ADDRESS>
</SMALL> </SMALL>
</BODY> </BODY>
</HTML> </HTML>
src/tools/backend/index.html
View file @ 0f3748a2
...@@ -3,42 +3,40 @@ ...@@ -3,42 +3,40 @@
<TITLE>How PostgreSQL Processes a Query</TITLE> <TITLE>How PostgreSQL Processes a Query</TITLE>
</HEAD> </HEAD>
<BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#FF0000" VLINK="#A00000" ALINK="#0000FF"> <BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#FF0000" VLINK="#A00000" ALINK="#0000FF">
<H1 ALIGN=CENTER> <H1>
How PostgreSQL Processes a Query How PostgreSQL Processes a Query
</H1> </H1>
<H2 ALIGN=CENTER> <H2>
by Bruce Momjian by Bruce Momjian
</H2> </H2>
<P> <P>
<CENTER> <IMG src="flow.gif" usemap="#flowmap" alt="flowchart">
<IMG src="flow.gif" usemap="#flowmap" alt="flowchart" border=0> <MAP name="flowmap" id="flowmap">
</CENTER> <AREA coords="125,35,245,65" HREF="backend_dirs.html#main" alt="main"></AREA>
<MAP name="flowmap"> <AREA coords="125,100,245,125" HREF="backend_dirs.html#postmaster" alt="postmaster"></AREA>
<AREA COORDS="125,35,245,65" HREF="backend_dirs.html#main"> <AREA coords="325,65,450,95" HREF="backend_dirs.html#libpq" alt="libpq"></AREA>
<AREA COORDS="125,100,245,125" HREF="backend_dirs.html#postmaster"> <AREA coords="125,160,245,190" HREF="backend_dirs.html#tcop" alt="tcop"></AREA>
<AREA COORDS="325,65,450,95" HREF="backend_dirs.html#libpq"> <AREA coords="325,160,450,190" HREF="backend_dirs.html#tcop" alt="tcop"></AREA>
<AREA COORDS="125,160,245,190" HREF="backend_dirs.html#tcop"> <AREA coords="125,240,245,265" HREF="backend_dirs.html#parser" alt="parser"></AREA>
<AREA COORDS="325,160,450,190" HREF="backend_dirs.html#tcop"> <AREA coords="125,300,250,330" HREF="backend_dirs.html#tcop" alt="tcop"></AREA>
<AREA COORDS="125,240,245,265" HREF="backend_dirs.html#parser"> <AREA coords="125,360,250,390" HREF="backend_dirs.html#optimizer" alt="optimizer"></AREA>
<AREA COORDS="125,300,250,330" HREF="backend_dirs.html#tcop"> <AREA coords="125,425,245,455" HREF="backend_dirs.html#optimizer_plan" alt="plan"></AREA>
<AREA COORDS="125,360,250,390" HREF="backend_dirs.html#optimizer"> <AREA coords="125,490,245,515" HREF="backend_dirs.html#executor" alt="executor"></AREA>
<AREA COORDS="125,425,245,455" HREF="backend_dirs.html#optimizer/plan"> <AREA coords="325,300,450,330" HREF="backend_dirs.html#commands" alt="commands"></AREA>
<AREA COORDS="125,490,245,515" HREF="backend_dirs.html#executor"> <AREA coords="75,575,195,605" HREF="backend_dirs.html#utils" alt="utils"></AREA>
<AREA COORDS="325,300,450,330" HREF="backend_dirs.html#commands"> <AREA coords="235,575,360,605" HREF="backend_dirs.html#catalog" alt="catalog"></AREA>
<AREA COORDS="75,575,195,605" HREF="backend_dirs.html#utils"> <AREA coords="405,575,525,605" HREF="backend_dirs.html#storage" alt="storage"></AREA>
<AREA COORDS="235,575,360,605" HREF="backend_dirs.html#catalog"> <AREA coords="155,635,275,665" HREF="backend_dirs.html#access" alt="access"></AREA>
<AREA COORDS="405,575,525,605" HREF="backend_dirs.html#storage"> <AREA coords="325,635,450,665" HREF="backend_dirs.html#nodes" alt="nodes"></AREA>
<AREA COORDS="155,635,275,665" HREF="backend_dirs.html#access"> <AREA coords="75,705,200,730" HREF="backend_dirs.html#bootstrap" alt="bootstrap"></AREA>
<AREA COORDS="325,635,450,665" HREF="backend_dirs.html#nodes">
<AREA COORDS="75,705,200,730" HREF="backend_dirs.html#bootstrap">
</MAP> </MAP>
<CENTER><EM> <EM>
Click on an item to see more detail or look at the full Click on an item to see more detail or look at the full
<A HREF="backend_dirs.html">index.</A> <A HREF="backend_dirs.html">index.</A>
</EM></CENTER> </EM>
<BR> <BR>
<BR> <BR>
</P>
<P> <P>
A query comes to the backend via data packets arriving through TCP/IP or A query comes to the backend via data packets arriving through TCP/IP or
...@@ -49,13 +47,13 @@ into tokens(words). The parser uses <A ...@@ -49,13 +47,13 @@ into tokens(words). The parser uses <A
HREF="../../backend/parser/gram.y">gram.y</A> and the tokens to identify HREF="../../backend/parser/gram.y">gram.y</A> and the tokens to identify
the query type, and load the proper query-specific structure, like <A the query type, and load the proper query-specific structure, like <A
HREF="../../include/nodes/parsenodes.h">CreateStmt</A> or <A HREF="../../include/nodes/parsenodes.h">CreateStmt</A> or <A
HREF="../../include/nodes/parsenodes.h">SelectStmt.</A><P> HREF="../../include/nodes/parsenodes.h">SelectStmt.</A></P><P>
The query is then identified as a <I>Utility</I> query or a more complex The query is then identified as a <I>Utility</I> query or a more complex
query. A <I>Utility</I> query is processed by a query-specific function query. A <I>Utility</I> query is processed by a query-specific function
in <A HREF="../../backend/commands"> commands.</A> A complex query, like in <A HREF="../../backend/commands"> commands.</A> A complex query, like
<I>SELECT, UPDATE,</I> and <I>DELETE</I> requires much more handling.<P> <I>SELECT, UPDATE,</I> and <I>DELETE</I> requires much more handling.</P><P>
The parser takes a complex query, and creates a The parser takes a complex query, and creates a
...@@ -67,7 +65,7 @@ Each table referenced in the query is represented by a <A ...@@ -67,7 +65,7 @@ Each table referenced in the query is represented by a <A
HREF="../../include/nodes/parsenodes.h"> RangeTableEntry,</A> and they HREF="../../include/nodes/parsenodes.h"> RangeTableEntry,</A> and they
are linked together to form the <I>range table</I> of the query, which are linked together to form the <I>range table</I> of the query, which
is generated by <A HREF="../../backend/parser/parse_clause.c"> is generated by <A HREF="../../backend/parser/parse_clause.c">
transformFromClause().</A> Query.rtable holds the query's range table.<P> transformFromClause().</A> Query.rtable holds the query's range table.</P><P>
Certain queries, like <I>SELECT,</I> return columns of data. Other Certain queries, like <I>SELECT,</I> return columns of data. Other
...@@ -78,16 +76,16 @@ placed in <A HREF="../../include/nodes/parsenodes.h">target list ...@@ -78,16 +76,16 @@ placed in <A HREF="../../include/nodes/parsenodes.h">target list
entries,</A> and linked together to make up the <I>target list</I> of entries,</A> and linked together to make up the <I>target list</I> of
the query. The target list is stored in Query.targetList, which is the query. The target list is stored in Query.targetList, which is
generated by <A generated by <A
HREF="../../backend/parser/parse_target.c">transformTargetList().</A><P> HREF="../../backend/parser/parse_target.c">transformTargetList().</A></P><P>
Other query elements, like aggregates(<I>SUM()</I>), <I>GROUP BY,</I> Other query elements, like aggregates(<I>SUM()</I>), <I>GROUP BY,</I>
and <I>ORDER BY</I> are also stored in their own Query fields.<P> and <I>ORDER BY</I> are also stored in their own Query fields.</P><P>
The next step is for the Query to be modified by any <I>VIEWS</I> or The next step is for the Query to be modified by any <I>VIEWS</I> or
<I>RULES</I> that may apply to the query. This is performed by the <A <I>RULES</I> that may apply to the query. This is performed by the <A
HREF="../../backend/rewrite">rewrite</A> system.<P> HREF="../../backend/rewrite">rewrite</A> system.</P><P>
The <A HREF="../../backend/optimizer">optimizer</A> takes the Query The <A HREF="../../backend/optimizer">optimizer</A> takes the Query
...@@ -96,18 +94,17 @@ HREF="../../include/nodes/plannodes.h">Plan,</A> which contains the ...@@ -96,18 +94,17 @@ HREF="../../include/nodes/plannodes.h">Plan,</A> which contains the
operations to be performed to execute the query. The <A operations to be performed to execute the query. The <A
HREF="../../backend/optimizer/path">path</A> module determines the best HREF="../../backend/optimizer/path">path</A> module determines the best
table join order and join type of each table in the RangeTable, using table join order and join type of each table in the RangeTable, using
Query.qual(<I>WHERE</I> clause) to consider optimal index usage.<P> Query.qual(<I>WHERE</I> clause) to consider optimal index usage.</P><P>
The Plan is then passed to the <A The Plan is then passed to the <A
HREF="../../backend/executor">executor</A> for execution, and the result HREF="../../backend/executor">executor</A> for execution, and the result
returned to the client. The Plan actually as set of nodes, arranged in returned to the client. The Plan actually as set of nodes, arranged in
a tree structure with a top-level node, and various sub-nodes as a tree structure with a top-level node, and various sub-nodes as
children.<P> children.</P><P>
There are many other modules that support this basic functionality. They There are many other modules that support this basic functionality. They
can be accessed by clicking on the flowchart.<P> can be accessed by clicking on the flowchart.</P>
<HR><P> <HR><P>
...@@ -117,19 +114,20 @@ Another area of interest is the shared memory area, which contains data ...@@ -117,19 +114,20 @@ Another area of interest is the shared memory area, which contains data
accessable to all backends. It has recently used data/index blocks, accessable to all backends. It has recently used data/index blocks,
locks, backend process information, and lookup tables for these locks, backend process information, and lookup tables for these
structures: structures:
</P>
<UL> <UL>
<LI>ShmemIndex - lookup shared memory addresses using structure names <LI>ShmemIndex - lookup shared memory addresses using structure names</LI>
<LI><A HREF="../../include/storage/buf_internals.h">Buffer <LI><A HREF="../../include/storage/buf_internals.h">Buffer
Descriptor</A> - control header for buffer cache block Descriptor</A> - control header for buffer cache block</LI>
<LI><A HREF="../../include/storage/buf_internals.h">Buffer Block</A> - <LI><A HREF="../../include/storage/buf_internals.h">Buffer Block</A> -
data/index buffer cache block data/index buffer cache block</LI>
<LI>Shared Buffer Lookup Table - lookup of buffer cache block addresses <LI>Shared Buffer Lookup Table - lookup of buffer cache block addresses
using table name and block number(<A using table name and block number(<A
HREF="../../include/storage/buf_internals.h"> BufferTag</A>) HREF="../../include/storage/buf_internals.h"> BufferTag</A>)</LI>
<LI>MultiLevelLockTable (ctl) - control structure for each locking <LI>MultiLevelLockTable (ctl) - control structure for each locking
method. Currently, only multi-level locking is used(<A method. Currently, only multi-level locking is used(<A
HREF="../../include/storage/lock.h">LOCKMETHODCTL</A>). HREF="../../include/storage/lock.h">LOCKMETHODCTL</A>).</LI>
<LI>MultiLevelLockTable (lock hash) - the <A <LI>MultiLevelLockTable (lock hash) - the <A
HREF="../../include/storage/lock.h">LOCK</A> structure, looked up using HREF="../../include/storage/lock.h">LOCK</A> structure, looked up using
relation, database object ids(<A relation, database object ids(<A
...@@ -137,31 +135,29 @@ HREF="../../include/storage/lock.h">LOCKTAG)</A>. The lock table ...@@ -137,31 +135,29 @@ HREF="../../include/storage/lock.h">LOCKTAG)</A>. The lock table
structure contains the lock modes(read/write or shared/exclusive) and structure contains the lock modes(read/write or shared/exclusive) and
circular linked list of backends (<A circular linked list of backends (<A
HREF="../../include/storage/proc.h">PROC</A> structure pointers) waiting HREF="../../include/storage/proc.h">PROC</A> structure pointers) waiting
on the lock. on the lock.</LI>
<LI>MultiLevelLockTable (xid hash) - lookup of LOCK structure address <LI>MultiLevelLockTable (xid hash) - lookup of LOCK structure address
using transaction id, LOCK address. It is used to quickly check if the using transaction id, LOCK address. It is used to quickly check if the
current transaction already has any locks on a table, rather than having current transaction already has any locks on a table, rather than having
to search through all the held locks. It also stores the modes to search through all the held locks. It also stores the modes
(read/write) of the locks held by the current transaction. The returned (read/write) of the locks held by the current transaction. The returned
<A HREF="../../include/storage/lock.h">XIDLookupEnt</A> structure also <A HREF="../../include/storage/lock.h">XIDLookupEnt</A> structure also
contains a pointer to the backend's PROC.lockQueue. contains a pointer to the backend's PROC.lockQueue.</LI>
<LI><A HREF="../../include/storage/proc.h">Proc Header</A> - information <LI><A HREF="../../include/storage/proc.h">Proc Header</A> - information
about each backend, including locks held/waiting, indexed by process id about each backend, including locks held/waiting, indexed by process id</LI>
</UL> </UL>
Each data structure is created by calling <A <P>Each data structure is created by calling <A
HREF="../../backend/storage/ipc/shmem.c">ShmemInitStruct(),</A> and the HREF="../../backend/storage/ipc/shmem.c">ShmemInitStruct(),</A> and the
lookups are created by <A lookups are created by <A
HREF="../../backend/storage/ipc/shmem.c">ShmemInitHash().</A><P> HREF="../../backend/storage/ipc/shmem.c">ShmemInitHash().</A></P>
<HR SIZE="2" NOSHADE> <HR>
<SMALL> <SMALL>
<ADDRESS>
Maintainer: Bruce Momjian (<A Maintainer: Bruce Momjian (<A
HREF="mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR> HREF="mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
Last updated: Mon Aug 10 10:48:06 EDT 1998 Last updated: Mon Aug 10 10:48:06 EDT 1998
</ADDRESS>
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