Update flowchart and backend descriptions.

diff --git a/src/tools/backend/index.html b/src/tools/backend/index.html
index e286b6d8c6655940add16b0ba5355c872c51771a..dbf78042a4653886038e8cb85004fc92c5aa6135 100644 (file)
--- a/src/tools/backend/index.html
+++ b/src/tools/backend/index.html
@@ -32,35 +32,35 @@ The parser takes the complex queries, and creates a
 Query structure that
 contains all the elements used by complex queries.  Query.qual holds the
 WHERE clause qualification, which is filled in by
-
 transformWhereClause().
-Each table is represented by a 
-RangeTableEntry,
-and they are linked together to form the range table for the
-query, and is generated by 
+Each table referenced in the query is represented by a 
+HREF="../../include/nodes/parsenodes.h"> RangeTableEntry, and they
+are linked together to form the range table of the query, which is
+generated by 
 makeRangeTable().  Query.rtable holds the queries range table.
 
 Certain queries, like SELECT, return columns of data.  Other queries,
 like INSERT and UPDATE, specify the columns modified by the query. 
-These columns references are converted to 
+These column references are converted to 
 HREF="../../include/nodes/primnodes.h"> Resdom entries, which are
 linked together to make up the target list of the query. The
-target list is stored in Query.targetList, and is generated by
+target list is stored in Query.targetList, which is generated by
 transformTargetList().
 
 Other query elements, like aggregates(SUM()), GROUP BY, ORDER BY are
-also stored in their own fields.
+also stored in their own Query fields.
 
 The next step is for the Query to be modified by any VIEWS or RULES that
 may apply to the query.  This is performed by the 
 HREF="../../backend/rewrite">rewrite system.
 
-The optimizer takes the Query structure, and generates an optimal
-Plan containing primitive
-operations to be performed by the executor to complete the query.  The
-path module
-determines the table join order and join type of each of the tables in
-the RangeTable, using Query.qual(WHERE clause) to consider optimal index
+The optimizer takes the Query
+structure, and generates an optimal
+Plan containing the
+primitive operations to be performed by the executor to execute the
+query.  The path module
+determines the best table join order and join type of each table in the
+RangeTable, using Query.qual(WHERE clause) to consider optimal index
 usage.
 
 The Plan is then passed to the 
@@ -76,21 +76,27 @@ table data/index blocks, locks, and backend information:
 ShmemIndex - contains an index of all other shared memory
 structures, allowing quick lookup of other structure locations in shared
 memory
-Buffer Descriptors - control header for shared memory buffer block
-Buffer Blocks - block of table/index data shared by all backends
+Buffer
+Descriptors - control header for shared memory buffer block
+
+Buffer Blocks
+- block of table/index data shared by all backends
 Shared Buf Lookup Table - lookup to see if a requested buffer
 is already in the shared memory area
-LockTable - lock table structure, specifiying table, lock types, and
+LockTable
+- lock table structure, specifiying table, lock types, and
 backends holding or waiting on lock
 LockTable (lock hash) - lookup of LockTable structures using
 table name
 LockTable (xid hash) - lookup of LockTable structures using
 transaction id
-Proc Header - information about each backend, including locks held/waiting, 
-indexed by process id
+Proc Header - information
+about each backend, including locks held/waiting,  indexed by process id
 
-Each structure is created by calling 
-HREF="../../backend/storage/ipc/shmem.c"> ShmemInitStruct().
+Each data structure is created by calling 
+HREF="../../backend/storage/ipc/shmem.c"> ShmemInitStruct(), and
+the lookup hashes are created by
+ShmemInitHash().
 
 
 




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