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Extract Latency Connected With Update to PK Columns (Doc ID 1621667.1)

Last updated on MARCH 02, 2021

Applies to:

Oracle GoldenGate - Version to [Release to 12.1]
Information in this document applies to any platform.


Poor performance and latency / lag from Extract process.

An AWR report indicates that Extract is issuing a statement of the following form :

SELECT ... from table  AS OF SCN :scn x WHERE ROWID = :rid

- All columns in the table are specified in the column list ;
- AS OF SCN is also shown .

A pstack from the Extract process shows the context under which the above statement is issued to be :

Thread 1 (Thread 0x7f6dc3dbd6f0 (LWP 82440)):

#0  0x000000329bc0d9eb in read () from /lib64/   <<< read
#1  0x00007f6dc5fff864 in snttread () from /u01/app/ggate/
#2  0x00007f6dc5ffe7f5 in nttfprd () from /u01/app/ggate/
#3  0x00007f6dc5ff2ba8 in nsbasic_brc () from /u01/app/ggate/
#4  0x00007f6dc5ff610b in nsbrecv () from /u01/app/ggate/
#5  0x00007f6dc5fe51d3 in nioqrc () from /u01/app/ggate/
#6  0x00007f6dc603df2d in ttcdrv () from /u01/app/ggate/
#7  0x00007f6dc5febbd5 in nioqwa () from /u01/app/ggate/
#8  0x00007f6dc5fd8395 in upirtrc () from /u01/app/ggate/
#9  0x00007f6dc5fde9e6 in kpurcsc () from /u01/app/ggate/
#10 0x00007f6dc5fd9a66 in kpuexec () from /u01/app/ggate/
#11 0x00007f6dc5fd8ed1 in OCIStmtExecute () from /u01/app/ggate/
#12 0x000000000063f179 in pk_fetch_cols(file_def*, DBOCI_stmt_def*, int, int, int*) ()         <<<<<
#13 0x000000000063fba4 in DBFETCH_fetch_pk_cols(void*, file_def*) ()
#14 0x0000000000508936 in fetchPKCols(file_def*) ()
#15 0x00000000005091e1 in DBFETCH_fetch_cols(file_def*, char*, int, short, int, int*, short*, int*) ()
#16 0x000000000050b28b in DBFETCH_checkFetchCols(file_def*, __std_rec_hdr*, char*, int, unsigned char*, char*, short*, long, int, pk_fetch_options_t*) ()
#17 0x00000000005686ca in replicate_io(file_def*, __std_rec_hdr*, char*, extr_ptr_def*, int*, int) ()
#18 0x0000000000566127 in process_extract_loop() ()
#19 0x0000000000578166 in main ()



FETCHOPTIONS FETCHPKUPDATECOLS is specified in Extract parameter file


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