What is the Z00R table? Do we need it? How much space does it take?

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Article Type: General
Product: Aleph
Product Version: 18.01

Description:
What is the Z00R table? Do we need it? How much space does it take?

Resolution:
The Z00R table contains a separate record for each field in each document in the database. (This table takes about 2.6 times the space of the z00: the z00r data component is about about 1.3 times as big as the z00 and the z00r_id / z00r_id1 index components are many times larger than the z00_id. Together these indexes are roughly equal to the z00r table itself. Thus, the z00r table + Oracle indexes is about 2.6 times as large as the z00 table + Oracle indexes.)

(You can see how much space the z00 is taking in util a/17/11/2. The “BYTES/1024” column shows the number of Kilobytes.)

The z00r table is not used by Aleph batch or online programs. It is intended for customer SQL: bib-record statistics and querying of fields not included in the Z13 or z13u short bib records --though fields containing diacritics may not display perfectly....

The TAB100 CREATE-Z00R flag of the tab10 table of the library's tab directory is used to control the creation of the Z00R records. If the flag is set to "Y", the Z00R records will be created.

The records are created by the "Update Short Bibliographic Record" (p_manage_07) batch process that also creates the Z13. [Note: in version 16.02, with rep_change 295, you can control whether you want to do just the z13, just the z00r, or both.]

But the Z00R's are also created by the regular io_z00 routine (each time a z00 is written out).

To avoid redundant creation of the Z00R we recommend setting TAB100 CREATE-Z00R to "N" in the initial load and then setting it to "Y" when you run the p_manage_07 (--and leaving it that way).

Article last edited: 4/2/2014