How to create Oracle 19c pluggable database PDB

Overview of multi-tenant container database architecture diagram Multi-tenant container database components: 1. There is only one CDB Root (CDB$ROOT), which contains the metadata and data dictionary information of the Root and all PDB databases. 2. There is only one Seed PDB (PDB$SEED). Its function is to create templates for other PDBs. It is a read-only […]

Play with Linux GDB & pdb

1. GDB debugging Use of watch -n command: # Print the current system memory usage on the terminal every 1 second watch -n 1 “cat /proc/meminfo” # Check all running processes in the current system every 1s # ps: View system processes; -e: Display all processes; -f: Full format # The ps -aux command is […]

GPDB-Miscellaneous Diseases-PlaceHolderVar

GPDB-Miscellaneous Diseases-PlaceHolderVar When upgrading from GPDB5 to GPDB6, the SQL that could be executed in the past cannot be executed. Error: PlaceHolderVar found where not expected! Is the syntax incompatible? postgres=# CREATE TABLE t1( id1 int) WITH (appendonly=true, compresstype=none, blocksize=8192) DISTRIBUTED BY (id1); postgres=# CREATE TABLE t4(id1 int, id2 text ) DISTRIBUTED BY (id1); postgres=# […]

Multi-tenancy: Plugging and unplugging of PDB archives (12.2)

In Oracle12.1, PDB can be extracted into an “.xml” file, which describes the contents of the PDB database. To move a PDB, you need to manually move the “.xml” file and all related database files. In addition to this feature, Oracle 12.2 also allows unplugging PDBs into “.PDB” archives. The generated archive contains “.xml” files […]

GPDB-Kernel Features-gp_interconnect_fc_method parameter

GPDB-Kernel Features-gp_interconnect_fc_method parameter The gp_interconnect_fc_method parameter controls which flow control method to use: capacity controls sending according to the receiver window; loss (default) controls sending according to packet loss speed. Loss is based on capacity, and the sending speed will be adjusted according to the packet loss. So how to solve this parameter to control […]