Add kv_list and refactor session_settings with it #95
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serprex
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Dec 13, 2025
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A new structure, kv_list, represents a list of key/value pairs. Its constructor takes a Postgres `List` argument, iterates over the keys and values, allocates memory for each, and copies them into the struct. It uses `malloc()` to allocate the memory, because the we store the value in a global that mustn't be subject to the GUC memory context. Use it in `chfdw_settings_assign_hook()` to create a `kv_list` from the `List` returned by `chfdw_parse_options()` and assign it to the `ch_session_settings_list` global, which can then be fetched via `chfdw_get_session_settings()`. The downside to this approach is that the new value must be parsed twice. We consider this acceptable, since it means they're no longer parsed for every query. While at it, change `chfdw_parse_options()` to use `pstrdup()` instead of `strdup`, since its memory is handled by a Postgres memory context (and surely was leaking before).
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Closing in favor of #94. |
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Compare with #94.
A new structure, kv_list, represents a list of key/value pairs. Its constructor takes a Postgres
Listargument, iterates over the keys and values, allocates memory for each, and copies them into the struct. It usesmalloc()to allocate the memory, because the we store the value in a global that mustn't be subject to the GUC memory context.Use it in
chfdw_settings_assign_hook()to create akv_listfrom theListreturned bychfdw_parse_options()and assign it to thech_session_settings_listglobal, which can then be fetched viachfdw_get_session_settings().The downside to this approach is that the new value must be parsed twice. We consider this acceptable, since it means they're no longer parsed for every query.
While at it, change
chfdw_parse_options()to usepstrdup()instead ofstrdup, since its memory is handled by a Postgres memory context (and surely was leaking before).