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54f7338fa1
(materialization into a tuple store) discussed on pgsql-hackers earlier. I've updated the documentation and the regression tests. Notes on the implementation: - I needed to change the tuple store API slightly -- it assumes that it won't be used to hold data across transaction boundaries, so the temp files that it uses for on-disk storage are automatically reclaimed at end-of-transaction. I added a flag to tuplestore_begin_heap() to control this behavior. Is changing the tuple store API in this fashion OK? - in order to store executor results in a tuple store, I added a new CommandDest. This works well for the most part, with one exception: the current DestFunction API doesn't provide enough information to allow the Executor to store results into an arbitrary tuple store (where the particular tuple store to use is chosen by the call site of ExecutorRun). To workaround this, I've temporarily hacked up a solution that works, but is not ideal: since the receiveTuple DestFunction is passed the portal name, we can use that to lookup the Portal data structure for the cursor and then use that to get at the tuple store the Portal is using. This unnecessarily ties the Portal code with the tupleReceiver code, but it works... The proper fix for this is probably to change the DestFunction API -- Tom suggested passing the full QueryDesc to the receiveTuple function. In that case, callers of ExecutorRun could "subclass" QueryDesc to add any additional fields that their particular CommandDest needed to get access to. This approach would work, but I'd like to think about it for a little bit longer before deciding which route to go. In the mean time, the code works fine, so I don't think a fix is urgent. - (semi-related) I added a NO SCROLL keyword to DECLARE CURSOR, and adjusted the behavior of SCROLL in accordance with the discussion on -hackers. - (unrelated) Cleaned up some SGML markup in sql.sgml, copy.sgml Neil Conway
80 lines
2.3 KiB
C
80 lines
2.3 KiB
C
/*-------------------------------------------------------------------------
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*
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* fd.h
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* Virtual file descriptor definitions.
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*
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*
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* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $Id: fd.h,v 1.37 2003/03/27 16:51:29 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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/*
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* calls:
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*
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* File {Close, Read, Write, Seek, Tell, MarkDirty, Sync}
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* {File Name Open, Allocate, Free} File
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*
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* These are NOT JUST RENAMINGS OF THE UNIX ROUTINES.
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* Use them for all file activity...
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*
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* File fd;
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* fd = FilePathOpenFile("foo", O_RDONLY, 0600);
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*
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* AllocateFile();
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* FreeFile();
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*
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* Use AllocateFile, not fopen, if you need a stdio file (FILE*); then
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* use FreeFile, not fclose, to close it. AVOID using stdio for files
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* that you intend to hold open for any length of time, since there is
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* no way for them to share kernel file descriptors with other files.
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*/
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#ifndef FD_H
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#define FD_H
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/*
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* FileSeek uses the standard UNIX lseek(2) flags.
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*/
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typedef char *FileName;
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typedef int File;
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/* GUC parameter */
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extern int max_files_per_process;
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/*
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* prototypes for functions in fd.c
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*/
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/* Operations on virtual Files --- equivalent to Unix kernel file ops */
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extern File FileNameOpenFile(FileName fileName, int fileFlags, int fileMode);
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extern File PathNameOpenFile(FileName fileName, int fileFlags, int fileMode);
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extern File OpenTemporaryFile(bool keepOverTxn);
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extern void FileClose(File file);
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extern void FileUnlink(File file);
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extern int FileRead(File file, char *buffer, int amount);
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extern int FileWrite(File file, char *buffer, int amount);
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extern long FileSeek(File file, long offset, int whence);
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extern int FileTruncate(File file, long offset);
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/* Operations that allow use of regular stdio --- USE WITH CAUTION */
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extern FILE *AllocateFile(char *name, char *mode);
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extern void FreeFile(FILE *);
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/* If you've really really gotta have a plain kernel FD, use this */
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extern int BasicOpenFile(FileName fileName, int fileFlags, int fileMode);
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/* Miscellaneous support routines */
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extern void closeAllVfds(void);
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extern void AtEOXact_Files(void);
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extern void RemovePgTempFiles(void);
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extern int pg_fsync(int fd);
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extern int pg_fdatasync(int fd);
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#endif /* FD_H */
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