17.05 - File System: Segments Released Columns - Teradata Database

Teradata Vantageā„¢ - Resource Usage Macros and Tables

prodname
Advanced SQL Engine
Teradata Database
vrm_release
17.00
17.05
created_date
June 2020
category
Administration
User Guide
featnum
B035-1099-170K
These columns identify the total disk memory segments released by the File System, as well as those segments that are dropped from memory during the log period. When a segment is released, the segment is either:
  • Forced (F)
  • Remains resident in memory (R)
  • Aged out of memory (A), from segments that are currently resident

Both the number of segments (Rels, Writes, Drps) and the size of the segments (RelKB,WriteKB, DrpKB) are counted. When a segment leaves memory, it must be written to disk only if the segment is dirty (Dy), that is, modified. Otherwise, the clean (Cn), that is, unmodified segment is simply dropped.

Most spool blocks for a small table remain resident when they are created and age there. Each of these will be counted as a dirty resident release (DyRRel columns). If a block survives in the cache, it would be reacquired (whenever the system creates spool data, a subsequent step will read it) and released again. The release will still be counted as a dirty resident release, since the block survived in a modified state. On the other hand, if there is contention for room in the FSG cache, the segment might be removed from memory. Because it is a modified segment, it must be written out first. This is counted as a dirty age write (DyAWrite columns). When it is reacquired it will no longer be modified, so the subsequent release will be counted as a clean resident release (CnRRel columns).

If the segments are modified, only DyAWrites, DyAWriteKB, CnADrps, and CnADrpKB columns are incremented.

If the segments are unmodified, only CnADrps and CnADrpKB columns are incremented.

To determine the clean segments that aged out of memory for the CnADrps column, subtract the DyAWrites value from the CnADrps value. To determine the clean segments that aged out of memory for the CnADrpKB column, subtract the DyAWriteKB value from the CnADrpKB value.

Full table modification operations make one pass on the table and modify each block only once. Since these operations do not access a block multiple times, there is no point keeping them in the cache. If a block that was examined did not contain any rows that qualify for the modification, when the block is released, it will be dropped from memory immediately (FDrp columns). However, if the block was modified, when it is released the system issues the write as part of the release so it is counted as a forced write (FWrite columns). Since the system also drops the block from memory as soon as the write is complete, this release is also counted as a forced drop (FDrp columns).

Column Name Mode Description Data Type
FileAPtDyRRels count Number of dirty append table or permanent journal table data block or cylinder index disk segment resident releases. FLOAT
FilePCiDyRRels count Number of dirty permanent cylinder index disk segment resident releases. FLOAT
FilePDbDyRRels count Number of dirty permanent data block disk segment resident releases. FLOAT
FileSCiDyRRels count Number of dirty regular or restartable spool cylinder index disk segment resident releases. FLOAT
FileSDbDyRRels count Number of dirty regular or restartable spool data block disk segment resident releases. FLOAT
FileTJtDyRRels count Number of dirty transient journal table or WAL data block or WAL cylinder index disk segment resident releases. FLOAT
FileAPtDyRRelsKB count KB released by FileAPtDyRRels. FLOAT
FilePCiDyRRelsKB count KB released by FilePCiDyRRels. FLOAT
FilePDbDyRRelsKB count KB released by FilePDbDyRRels. FLOAT
FileSCiDyRRelsKB count KB released by FileSCiDyRRels. FLOAT
FileSDbDyRRelsKB count KB released by FileSDbDyRRels. FLOAT
FileTJtDyRRelsKB count KB released by FileTJtDyRRels. FLOAT
FileAPtFWrites count Number of append table or permanent journal table data block or cylinder index disk segment forced releases or specific I/O requests causing an immediate physical write. FLOAT
FilePCiFWrites count Number of permanent cylinder index disk segment forced releases or specific I/O requests causing an immediate physical write. FLOAT
FilePDbFWrites count Number of permanent data block disk segment forced releases or specific I/O requests causing an immediate physical write. FLOAT
FileSCiFWrites count Number of regular or restartable spool cylinder index disk segment forced releases or specific I/O requests causing an immediate physical write. FLOAT
FileSDbFWrites count Number of regular or restartable spool data block disk segment forced releases or specific I/O requests causing an immediate physical write. FLOAT
FileTJtFWrites count Number of transient journal table or WAL data block or WAL cylinder index disk segment forced releases or specific I/O requests causing an immediate physical write. FLOAT
FileAPtFWriteKB count KB written by FileAPtFWrites. FLOAT
FilePCiFWriteKB count KB written by FilePCiFWrites. FLOAT
FilePDbFWriteKB count KB written by FilePDbFWrites. FLOAT
FileSCiFWriteKB count KB written by FileSCiWrites. FLOAT
FileSDbFWriteKB count KB written by FileSDbFWrites. FLOAT
FileTJtFWriteKB count KB written by FileTJtFWrites. FLOAT
FileAPtDyAWrites count Number of dirty append table or permanent journal table data block or cylinder index disk segments aged out of memory causing a delayed physical write. FLOAT
FilePCiDyAWrites count Number of dirty permanent cylinder index disk segments aged out of memory causing a delayed physical write. FLOAT
FilePDbDyAWrites count Number of dirty permanent data block disk segments aged out of memory causing a delayed physical write. FLOAT
FileSCiDyAWrites count Number of dirty regular or restartable spool cylinder index disk segments aged out of memory causing a delayed physical write. FLOAT
FileSDbDyAWrites count Number of dirty regular or restartable spool data block disk segments aged out of memory causing a delayed physical write. FLOAT
FileTJtDyAWrites count Number of dirty transient journal table or WAL data block or WAL cylinder index disk segments aged out of memory causing a delayed physical write. FLOAT
FileAPtDyAWriteKB count KB written by FileAPtDyAWrites. FLOAT
FilePCiDyAWriteKB count KB written by FilePCiDyAWrites. FLOAT
FilePDbDyAWriteKB count KB written by FilePDbDyAWrites. FLOAT
FileSCiDyAWriteKB count KB written by FileSCiDyAWrites. FLOAT
FileSDbDyAWriteKB count KB written by FileSDbDyAWrites. FLOAT
FileTJtDyAWriteKB count KB written by FileTJtDyAWrites. FLOAT
FileAPtCnRRels count Number of clean append table or permanent journal table data block or cylinder index disk segment resident releases. FLOAT
FilePCiCnRRels count Number of clean permanent cylinder index disk segment resident releases. FLOAT
FilePDbCnRRels count Number of clean permanent data block disk segment resident releases. FLOAT
FileSCiCnRRels count Number of clean regular or restartable spool cylinder index disk segment resident releases. FLOAT
FileSDbCnRRels count Number of clean regular or restartable spool data block disk segment resident releases. FLOAT
FileTJtCnRRels count Number of clean transient journal table or WAL data block or WAL cylinder index disk segment resident releases. FLOAT
FileAPtCnRRelKB count KB released by FileAptCnRRels. FLOAT
FilePCiCnRRelKB count KB released by FilePCiCnRRels. FLOAT
FilePDbCnRRelKB count KB released by FilePDbCnRRels. FLOAT
FileSCiCnRRelKB count KB released by FileSCiCnRRels. FLOAT
FileSDbCnRRelKB count KB released by FileSDbCnRRels. FLOAT
FileTJtCnRRelKB count KB released by FileTJtCnRRels. FLOAT
FileAPtFDrps count Number of append table or permanent journal table data block or cylinder index disk segment forced releases causing an immediate memory drop. FLOAT
FilePCiFDrps count Number of permanent cylinder index disk segment forced releases causing an immediate memory drop. FLOAT
FilePDbFDrps count Number of permanent data block disk segment forced releases causing an immediate memory drop. FLOAT
FileSCiFDrps count Number of regular or restartable spool cylinder index disk segment forced releases causing an immediate memory drop. FLOAT
FileSDbFDrps count Number of regular or restartable spool data block disk segment forced releases causing an immediate memory drop. FLOAT
FileTJtFDrps count Number of transient journal table or WAL data block or WAL cylinder index disk segment forced releases causing an immediate memory drop. FLOAT
FileAPtFDrpKB count KB dropped by FileAPtFDrps. FLOAT
FilePCiFDrpKB count KB dropped by FilePCiFDrps. FLOAT
FilePDbFDrpKB count KB dropped by FilePDbFDrps. FLOAT
FileSCiFDrpKB count KB dropped by FileSCiFDrps. FLOAT
FileSDbFDrpKB count KB dropped by FileSDbFDrps. FLOAT
FileTJtFDrpKB count KB dropped by FileTJtFDrps. FLOAT
FileAPtCnADrps count Number of clean append table or permanent journal table data block or cylinder index disk segments aged out of memory. FLOAT
FilePCiCnADrps count Number of clean permanent cylinder index disk segments aged out of memory. FLOAT
FilePDbCnADrps count Number of clean permanent data block disk segments aged out of memory. FLOAT
FileSCiCnADrps count Number of clean regular or restartable spool cylinder index disk segments aged out of memory. FLOAT
FileSDbCnADrps count Number of clean regular or restartable spool data block disk segments aged out of memory. FLOAT
FileTJtCnADrps count Number of clean transient journal table or WAL data block or WAL cylinder index disk segments aged out of memory. FLOAT
FileAPtCnADrpKB count KB dropped by FileAPtCnADrps. FLOAT
FilePCiCnADrpKB count KB dropped by FilePCiCnADrps. FLOAT
FilePDbCnADrpKB count KB dropped by FilePDbCnADrps. FLOAT
FileSCiCnADrpKB count KB dropped by FileSCiCnADrps. FLOAT
FileSDbCnADrpKB count KB dropped by FileSDbCnADrps. FLOAT
FileTJtCnADrpKB count KB dropped by FileTJtCnADrps. FLOAT
FileAPtRelsOther count Total number of scratch append table or permanent journal table data block or cylinder index disk segments released as part of them being deleted. FLOAT
FilePCiRelsOther count Total number of scratch permanent cylinder index disk segments released as part of them being deleted. FLOAT
FilePDbRelsOther count Total number of scratch permanent data block disk segments released as part of them being deleted. FLOAT
FileSCiRelsOther count Total number of scratch regular or restartable spool cylinder index disk segments released as part of them being deleted. FLOAT
FileSDbRelsOther count Total number of scratch regular or restartable spool data block disk segments released as part of them being deleted. FLOAT
FileTJtRelsOther count Total number of scratch transient journal table or WAL data block or WAL cylinder index disk segments released as part of them being deleted. FLOAT
FileAPtRelOtherKB count Total number of scratch append table or permanent journal table data block or cylinder index disk segments released in KB. FLOAT
FilePCiRelOtherKB count Total number of scratch permanent cylinder index disk segments released in KB. FLOAT
FilePDbRelOtherKB count Total number of scratch permanent data block disk segments released in KB. FLOAT
FileSCiRelOtherKB count Total number of scratch regular or restartable spool cylinder index disk segments released in KB. FLOAT
FileSDbRelOtherKB count Total number of scratch regular or restartable spool data block disk segments released in KB. FLOAT
FileTJtRelOtherKB count Total number of scratch transient journal table or WAL data block or WAL cylinder index disk segments released in KB. FLOAT