Enable users to specify a custom schema name for Postgres pgvector

[paulonasc]

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Feature request

As a user of LangChain, I want to be able to specify a custom database schema at runtime when initializing the PGVector class.

This feature proposal aims to enhance the LangChain framework by enabling dynamic specification of database schema names when initializing the PGVector class. This functionality will allow users to set custom schemas for their database tables directly through the class constructor, thereby facilitating decoupling.

Relevant Discussion: #18883

Motivation

In current implementations of the LangChain framework, the database table name is hardcoded without a schema name being specified, therefore having it default to public. This makes the PGVector connector lack the flexibility needed for dynamic configuration during runtime. This limitation poses challenges such as in multi-tenant architectures where different clients or projects may require separate schemas.

It is frustrating to have to manually adjust the database schema within the codebase.

Proposal (If applicable)

No response