1 / 13

Managing Large Procedure Files

Managing Large Procedure Files. Tom Thoresen. Agenda. Procedure file organization Fast/Unload Enhancements Fast/Reload Enhancements. Procedure File Organization. Model204’s general purpose file system Allocated in ‘pages’ of course of 6184 bytes Two types of pages Directory pages

yehudi
Download Presentation

Managing Large Procedure Files

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Managing Large Procedure Files Tom Thoresen

  2. Agenda • Procedure file organization • Fast/Unload Enhancements • Fast/Reload Enhancements

  3. Procedure File Organization • Model204’s general purpose file system • Allocated in ‘pages’ of course of 6184 bytes • Two types of pages • Directory pages • Text pages • Directory pages contain information about the actual files (or procedures) • Text pages contain the actual records

  4. Procedure File Organization • All procedure file space is in Table D • This wasn’t always the case • Historians tell us procedures once were in the FCT • Earlier versions of the procedure file only allowed for numbers, not names • Procedure numbers still exist – each procedure still has an internal number • This number is used for handling procedure aliases

  5. Procedure File Organization • PD pages are allocated in groups called “chunks” • This is specified by the file parameter PDSIZE • Refers to the number of pages in a “chunk” • Default is 3, some performance improvement can be had for large procedure files by increasing this value to its maximum – 255 • Larger PDSIZE can speed the process of locating a procedure

  6. Procedure File Organization • Storing a procedure • The procedure name is hashed to locate a chunk where the name will reside • Hashing assumes the procedure will be read much more often than written • Name is stored in reserved part of dictionary page • PDSTRPPG sets maximum number of procedure names for a dictionary page • Default is 128 – this is usually adequate • First text page (if any) is allocated and saved as part of dictionary entry

  7. Procedure File Organization • Text pages are allocated as needed • Text pages cannot be shared – even if 1 byte is used the remaining space is reserved • Records are delimited by the EOC character • Records are limited to 255 bytes • No record may be divided among text pages • If record doesn’t fit, it must be written to a new text page

  8. Unloading Procedures with Fast/Unload • Available with Fast/Unload Version 4.2 • Only for Unload All Information unloads • New record types for UAI • PD Header record • Contains number of PD pages in file • PROC record • Name of procedure, extended procedure data, and procedure text • ALIAS record • Contains name of procedure and alias

  9. Unloading Procedures with Fast/Unload • FSTATS now produced for procedures • Requires, of course, the FastUnload field statistics package • FSTATS also required to use automatic PDSIZE setting feature of Fast/Reload • PD header record only produced for UAI with FSTAT option

  10. Unloading Procedures with Fast/Unload FUNL0055 TOMWEB Procedure Dictionary statistics : 7 Chunks in PD 9 Pages per chunk 63 Total pages in PD 64 Hash cells per page 4,032 Total number of cells 1,747 Total number of procs 0 Total number of aliases 22 Average length of proc/alias names 10,436 Total text pages 32,722 Average proc length in bytes 5 Average proc length in pages FUNL0004 End of Fast Unload

  11. Loading procedures with Fast/Reload • SirMods 6.5 + • Standard Fast/Reload LAI will load any procs present in UAI data • NOPROCS LAI option will suppress loading of procedures • Increase MINBUF/MAXBUF • Procedure reload uses Model 204 disk buffer monitor • Unlike TABLEB load which uses private full-track buffers • Use as many buffers as storage capacity permits

  12. Loading procedures with Fast/Reload • Requirements for using automatic PDSIZE • UAI done with FSTATs option • Procedure dictionary must be ‘clean’ – no existing procedures • Current PDSIZE must be 3 (the default) • Intention is to preserve any ‘manual’ setting • Number of unloaded PD pages > default PDSIZE • Reload will terminate if any procedure already exists in target procedure file

  13. Loading procedures with Fast/Reload FUNL0055 TOMWEB Procedure Dictionary statistics : 1 Chunks in PD 63 Pages per chunk 63 Total pages in PD 128 Hash cells per page 8,064 Total number of cells 1,747 Total number of procs 0 Total number of aliases 22 Average length of proc/alias names 10,408 Total text pages 32,722 Average proc length in bytes 5 Average proc length in pages FUNL0004 End of Fast Unload

More Related